Good Diet, Bad Study

Posted on February 27, 2013 by Dr. Barry Sears

As the creator of the Zone Diet, I am a strong believer in the Mediterranean diet as a lifetime dietary program for good health. In fact, the Zone Diet can be considered to be the evolution of the Mediterranean diet as it provides even greater anti-inflammatory benefits. That being said, this week’s New England Journal of Medicine contained an article on using the Mediterranean diet with high-risk cardiovascular patients that got great press based on some really poor science¹. Let’s get to the bad science first.

The researchers compared two “Mediterranean” diets (one with extra nuts and the other with extra olive oil) to a low-fat diet. Unfortunately, they were unable to get the subjects to follow a low-fat diet. If you are a follower of Dean Ornish, then a low-fat diet means less than 10% of your calories coming from fat. Using that definition of a low-fat diet, you have to throw out one-third of the subjects because they couldn’t reduce their fat intake below 37% of total calories. In fact, at the end of this five-year study, the percentages of protein, carbohydrate, and fat in the diets of all three groups were approximately the same. As a result, you are left with a study with two groups of subjects being compared to another group of subjects who really didn’t change their diet that much.

Even Dean Ornish pointed this out in his rebuttal blog in the Huffington Post to this study². He wrote that if people had followed his low-fat diet, then the results would have been much different. Well, actually when high-risk cardiovascular patients did follow his diet in a study done 15 years ago, those on his low-fat diet had twice the deaths compared to those in the control group³. So maybe it’s a good thing that the low-fat group couldn’t follow the prescribed low-fat diet.

The reason for adverse effects of a low-fat, low-protein, very high-carbohydrate diet for cardiovascular patients is quite clear. Those subjects following his high-carbohydrate, low-fat, and low-protein diet developed insulin resistance as evidenced by a significant increase in their triglyceride-to-HDL ratio³. If you already have had a heart attack, then an increase in insulin resistance and the accompanying increase in inflammation are almost certain to push you over the edge.

If you really dig deeper into the supplemental material (Table S7 to be exact) of this article (as most journalists neglected to do), you are remarkably unimpressed by the changes in the diet over a five-year period except that the people who got free olive oil and free nuts were consuming more free olive oil and free nuts than those who were not getting free food.

Now, back to the clinical results — a strange brew of stroke, heart attack, and death. Usually when you include a lot of different clinical end points as your primary goal, it means you are not very confident about seeing any real striking clinical benefit. Stroke is primarily associated with high blood pressure, whereas heart attack is associated with the rupture of small vulnerable plaques leading to blockage of the coronary arteries. I personally like death as a clinical end point since you can’t cheat on its definition, thus making it harder to manipulate your statistics to prove your point.

So let’s look at the individual clinical endpoints. There was a reduction in strokes that was statistically significant. Unfortunately, there was no statistically significant reduction in either heart attacks or death. For such a large study, these clinical results are not too impressive. Maybe if the researchers had actually gotten the low-fat group to reduce their fat intake to less than 10% of calories (instead of going from 39% to 37% of calories), there might have been more deaths in that group, which would have made the other two Mediterranean diet groups look better.

Virtually every cardiovascular researcher knows that fatty acid composition of the plasma is an important factor in the prediction of future cardiovascular events. Unfortunately, the authors of the New England Journal of Medicine article apparently didn’t think so. Obviously, they measured one fatty acid (alpha linolenic acid) in Figure 5S (again buried deep in the supplemental material), but somehow forgot to report the other 34 fatty acids also found in the plasma. Two of the most important of these unreported fatty acids would have included arachidonic acid (AA) and eicosapentaenoic (EPA). The AA/EPA ratio in the blood is the best marker of cellular inflammation that drives heart disease⁴. You would think inclusion of information on this ratio (or at least providing the fatty acid levels) would be important since a far larger JELIS study demonstrated that the lowering of the AA/EPA ratio resulted in a significant reduction of cardiovascular events⁵.

In contrast to this poorly executed study, there exists a far more powerful study conducted nearly 20 years ago on the benefits of a stricter Mediterranean diet. This is was the Lyon Diet Heart Study⁶. The primary clinical difference between this new study and older Lyon Diet Heart Study is that the Lyon Diet Heart Study generated a 65% reduction in overall cardiovascular mortality, a complete reduction in cardiac sudden death, and 44% reduction in all-cause mortality^6,7. Those are clinical end points to get excited about. On the other hand, this New England Journal of Medicine article showed no impact on mortality. The only striking difference between the two groups in the Lyon Diet Heart Study was the restriction of omega-6 fatty acids in the experimental group. You find omega-6 fatty acids in vegetable oils like corn, safflower, and sunflower oils. They accomplished this dietary change by giving the subjects in the experimental groups margarines rich in omega-3 fats and trans fats. Although there was a dramatic decrease in death between the two groups in the Lyon Diet Heart Study, there were no differences in weight, BMI, blood pressure, cholesterol (good and bad), and blood lipids between the two groups. In other words, all the usual suspects in heart disease were eliminated. The only differences between the two groups were in the fatty acids, both linoleic acid and the AA/EPA ratio. If you again go back to bowels of the recent New England Journal article (in supplemental Table S7), you find out that the levels of linoleic acid (an omega-6 fatty acid) as analyzed from dietary records of the subjects was between 5 and 6% in both of the Mediterranean diets. In the Lyon Diet Heart Study, the investigators were able to reduce to the linoleic levels to 3.6%, which is similar to levels found in the Japanese (actually Okinawans), who have the lowest cardiovascular mortality in the developed world (8). The subjects in the control group of the Lyon Diet Heart Study had a nearly 50% higher level of linoleic acid in their blood compared to the experimental group⁸. However, those subjects following the “Mediterranean” diets in the new study had even higher levels of linoleic acid than those in the control group of the Lyon Diet Heart Study. That is the most likely reason there wasn’t any change in cardiovascular mortality or overall mortality in the New England Journal of Medicine study. Unlike this more “modern” study, the Lyon researchers further demonstrated that the AA/EPA ratio was reduced by some 30% (from 9 to 6.2) in the active group compared to the control group, and this resulted in a 65% reduction of cardiovascular death.

Bottom line, unless you dramatically reduce omega-6 intake by reducing your consumption of vegetable oils (such as corn, soy and safflower oils), you will not get clear-cut clinical results (like reduction in death) no matter how much hype the media give to the research.

As I said earlier, the Zone Diet can be considered to be the evolution of the Mediterranean diet because it represents a superior dietary program to control inflammation, the true underlying cause of heart disease. This is because the Zone Diet dramatically reduces white carbohydrates (pasta, bread, rice, and potatoes) and replaces them with increased amounts of colorful carbohydrates (vegetables and fruits). Unlike the New England Journal of Medicine article where the subjects were consuming about 5 servings a day of vegetables and fruits, the Zone Diet recommends 10 servings per day. Rather than keeping the linoleic acid content at 6% of the calories (the American Heart Association recommends 10-15%) or even at the 3.6% level as in the Lyon Diet Heart Study, the Zone Diet recommends fewer than 2% of total calories should consist of linoleic acid. Like the JELIS study, the Zone Diet recommends extra supplemental of omega-3 fatty acids to reduce the AA/EPA ratio to 1.5 or less.

Although the jury may still be out on the Mediterranean diet (especially after this poorly executed study) for the primary prevention of heart disease, the data from secondary prevention studies (5-7) strongly suggest that the Zone Diet may be the dietary approach you want to follow if reducing mortality is your personal clinical end point.

References

Estuch R et al. “Primary prevention of cardiovascular disease with a Mediterranean diet.” N Engl J Med 368: doi10.1056/NEJMoa1200303 (2013)
Ornish D. “Does a Mediterranean diet really beat a low-fat for health?” HuffPost Healthy Living Feb 25 (2013)
Ornish D et al. “Intensive lifestyle changes for reversal of coronary heart disease.” JAMA 280: 2001-2007 (1998)
Sears B. The Anti-Inflammation Zone. Regan Books. New York, NY (2005)
Yokoyama M et al. “Effects of eicosapentaenoic acid on major coronary events in hypercholesterolaemic patients (JELIS): a randomized open-label, blinded endpoint analysis.” Lancet 369: 1090-1098 (2007)
de Lorgeril et al. “Mediterranean alpha-linolenic-rich diet in secondary prevention of coronary heart disease.” Lancet 343: 1454-1459 (1994)
de Lorgeril et al. “Mediterranean diet, traditional risk factors, and the rate of cardiovascular complications after myocardial infarction.” Circulation 99: 779-785 (1999)
Kagawa Y et al. “Eicosapolyenoic acids of serum lipids of Japanese islanders with low incidence of cardiovascular disease.” J Nutr Sci Vitaminol 28: 441-453 (1982)

Harvard explains why people regain weight with the Atkins diet

Posted on October 9, 2012 by Dr. Barry Sears

A study from Harvard Medical School explains that even though people can lose weight on a ketogenic diet, all lost weight usually rapidly returns.

Ketogenic diets have been recommended for decades for rapid weight loss. The most famous is the Atkins diet. Ketogenic diets are based on high-protein and very low-carbohydrate intake. For the past 40 years such diets have been routinely used in America for weight loss, yet America remains in the midst of a growing epidemic of obesity. While ketogenic diets can induce initial weight loss, all lost weight usually rapidly returns, resulting in more weight (and even more fat) than when the person started the ketogenic diet.

For many years it was thought that such weight regain was due to poor dietary compliance. Now Harvard Medical School in an article in the June 27, 2012, issue of the Journal of the American Medical Association shows the reason for weight regain is more ominous than simple dietary non-compliance. In carefully controlled studies Harvard researchers demonstrated that on a ketogenic diet the levels of the hormone cortisol increase by 18%, and the levels of active thyroid hormone (T3) control metabolism decrease by 12% (1).

The effect of increased cortisol is to cause rapid fat accumulation, as any patient who has ever used prescription cortisol-like drugs knows. It also causes depression of the immune system, loss of memory, and thinning of the skin. These are also hallmarks of the acceleration of the aging process. Furthermore, the lowering of the active form of the thyroid hormone slows down the metabolism, making even seemingly small increases in calorie intake result in increased body fat accumulation. Besides setting you up to regain all the lost weight, the Atkins diet apparently also increases the rate of aging.

However, many people seem willing to continue to try such ketogenic diets in hopes of losing weight quickly. Yet highly controlled studies I published in the world’s most prestigious nutrition journal in world more than six years ago demonstrated that is simply not a true statement (2). In this study either a ketogenic diet (the Atkins diet) or a non-ketogenic diet (the Zone Diet) were compared in obese individuals. For the first six weeks all meals for both groups were prepared in a metabolic kitchen at Arizona State University (in essence treating subjects like lab rats). Both diets contained an equal number of calories.

When it came to weight loss, the subjects following the Zone Diet actually lost slightly more weight than as those on the ketogenic diet during the initial six-week period as shown in Figure 1.

Figure 1. Weight Loss (Zone Diet in open circles, Atkins diet in black squares)

Relative to fat loss on the non-ketogenic Zone Diet, their loss of body fat was again superior to the Atkins diet as shown in Figure 2. Fat loss is far more important than weight loss since all the health benefits from weight loss come from the loss of excess body fat; not from the loss of retained water or loss of muscle mass.

Figure 2. Fat Loss (Zone Diet in open circles, Atkins diet in black squares)

When the subjects continued on the respective diets for another four weeks (but now preparing meals on their own), those subjects on the non-ketogenic Zone Diet continued to lose even more weight and body fat, whereas those on the ketogenic Atkins diet did not. They had reached a plateau. The new research from Harvard Medical explains why.

One of the major problems in following a calorie-restricted diet is lack of energy. In this same study, the subjects on the Zone Diet demonstrated improved daily energy compared to those on the Atkins diet. In another publication using the same subjects, we also demonstrated that those subjects following the Zone Diet had greater performance in endurance testing compared to those following the ketogenic Atkins diet (3).

Figure 3. Energy levels (Zone Diet in open circles, Atkins diet in black squares)

For the past 40 years, ketogenic diets (like the Atkins diet) have failed to treat obesity in America. That is why one relies upon science, not hype, to determine which is the best diet to lose weight (and really body fat), keep it off, and increase energy. Continuing research from Harvard Medical School since 1999 demonstrates that the Zone Diet is the best dietary program to accomplish both goals (1,4-7). And the one thing Harvard will always tell you is that they are never wrong.

References

Ebbeling CB, Swain JF, Feldman HA, Wong WA, Hachey DL, Garcia-Logo E, and Ludwig DD. “Effects of dietary composition on energy expenditure during weight loss maintenance.” JAMA 307: 267-2634 (2012)
Johnston, C.S., Tjonn, S., Swan, P.D., White A., Hutchins H., and Sears B. “Ketogenic low-carbohydrate diets have no metabolic advantage over nonketogenic low-carbohydrate diets.” Am J Clin Nutr 83: 1055-1061 (2006)
White AM, Johnston CS, Swan PD, Tjonn SL, and Sears B. “Blood ketones are directly related to fatigue and perceived effort during exercise in overweight adults adhering to low-carbohydrate diets for weight loss: A pilot study.” J Am Diet Assoc 107: 1792-1796 (2007)
Ludwig, DS, Majzoub AJ, Al-Zahrani A, Dallal GE, Blanco I, and Roberts SB. “High glycemic index foods, overeating, and obesity.” Pediatrics 103: e26 (1999)
Agus MSD, Swain JF, Larson CL, Eckert EA, and Ludwig DS. “Dietary composition and physiologic adaptations to energy restriction.” Am J Clin Nutr 71:901–907 (2000)
Pereira MA, Swain J, Goldfine AB, Rifai N, and Ludwig DS. “Effect of low-glycemic diet on resting energy expenditure and heart disease risk factors during weight loss.” JAMA. 292: 2482-2490 (2004)
Ebbeling CB, Leidig MM, Feldman HA, Lovesky MM, and Ludwig DS. “Effects of a low–glycemic load vs. low-fat diet in obese young adults”. JAMA 297: 2092-2102 (2007)

Meta-analysis study on fish oil effectiveness is fatally flawed

Posted on September 14, 2012 by Dr. Barry Sears

One of the events in the food industry you never want to see is the making of sausage where sometimes good cuts of meat are combined with items you would never want to eat.

The same is true of meta-analysis studies in medical research. Meta-analysis means that you take a lot of different studies (some good, some not so good) using different patient populations, different inclusion criteria, different protocols, and different outcome criteria and mix them together to get a conclusion that often demonstrates a non-result. The best example of this is the recent study in the Journal of the American Medical Association that combined a wide number of studies using fish oil supplements to come up with the conclusion that omega-3 fatty acids have no benefit (1). So let’s take a look at this study in a little more detail.

First, it is always useful to look at the investigators. In this case, the authors are from Greece (not exactly a hotspot of high-quality clinical research since Aristotle), and to my knowledge none of them has been involved in any actual cardiovascular intervention studies in the past, let alone any work with omega-3 fatty acids. (I believe a little background is a good foundation to build from, but then call me crazy.)

Second, the average dose used in these studies was 1.5 grams of omega-3 fatty acids per day. Surprisingly, the American Heart Association recommends more than double this dose to reduce triglycerides, a known risk factor for heart disease (apparently not in Greece since the authors ignored this fact). This would indicate the authors were making conclusions based on placebo doses of omega-3 fatty acids. Usually a placebo dose gives placebo effects, which was confirmed in their meta-analysis. Furthermore, just giving a dose of anything is meaningless unless it is reducing a measureable clinical parameter in the blood that has a relationship to the disease condition being studied. For example, if I gave a statin dose that reduced LDL cholesterol levels from 250 mg/dl to 245 mg/dl, I wouldn’t expect any therapeutic benefits unless I gave enough statin drug to reduce the LDL cholesterol level to less than 130 mg/dl, if not much lower.

So what is a good dose of omega-3 fatty acids? As I have already mentioned, the American Heart Association recommends 3.4 grams of EPA and DHA per day to lower triglyceride levels. However, I believe a better marker is the amount of omega-3 fatty acids needed to reduce the AA/EPA ratio to the levels found in the Japanese population, which has the lowest levels of cardiovascular events in the world. Recent studies with healthy Americans indicate that would take between 5 and 7.5 grams of EPA and DHA per day (2). Again, this indicates that the dose of omega-3 fatty acids in this meta-analysis was providing a placebo dose.

Third, another problem with meta-analysis is conflicting protocols. In this study, almost half the patients came from two just studies: The GISSI study and the JELIS study. The GISSI study (more than 11,000 patients) indicated that omega-3 fatty acid supplementation on the foundation of a Mediterranean diet could reduce sudden cardiovascular death rate by 45% versus a placebo and reduced overall cardiovascular death by 20% (3). This study was criticized because the care that all groups were receiving didn’t include statins (since they were not yet approved). After all, the thinking for a typical cardiologist is that there is no reason to use omega-3 fatty acids if you can simply give a statin drug instead.

That faulty thinking was addressed by the JELIS study in which all the patients (about 18,000) were getting statins (4). Unlike the GISSI study, the AA/EPA ratio was measured in these patients. The initial AA/EPA ratio was 1.6 (a level requiring Americans to take about 5 to 7.5 grams of omega-3 fatty acids per day just to reach that starting point), and then even more EPA was added to the active group. After 4 ½ years, those Japanese patients getting the statins and extra fish oil had another 20% reduction in cardiovascular events over and above those getting the statins and an equivalent amount of supplemented olive oil. The take-home lesson from the JELIS study was that any physician who didn’t prescribe supplemental omega-3 fatty acids along with statins was simply practicing bad medicine.

Meta-analysis studies are supposed to make up for potential shortcomings in small clinical trials (like the ones used to approve virtually all pharmaceutical drugs). In the hands of unqualified researchers who have little understanding of the field or compound being studied, a meta-analysis can become an instrument for the mass confusion generated by this recent article in the Journal of American Medical Association.

The bottom line is that you need adequate doses of natural compounds to generate a therapeutic effect. The levels of these doses of natural compounds will always be far greater than with drugs, but also with far fewer side-effects. If you give a placebo dose of a natural compound, then expect a placebo result. But please don’t try to pass off such an obvious result as “science”.

References

Rizos EC et al. “Association between omega-3 fatty acid supplementation and risk of major cardiovascular disease events.” JAMA 308: 1024-1038 (2012)
Yee LD et al. “Omega-3 fatty acid supplements in women at high risk of breast cancer have dose-dependent effects on breast adipose tissue fatty acid composition.” Amer J Clin Nutr 91: 1185-1194 (2010)
GISSI-Prevenzione Investigators. “Dietary supplementation with n-3 polyunsaturated fatty acids and vitamin E after myocardial infarction: results of the GISSI-Prevenzione trial.” Lancet 354: 447-455 (1999)
Yokoyama M et al. “Effects of eicosapentaenoic acid on major coronary events in hypercholesterolaemic patients (JELIS): a randomized open-label, blinded endpoint analysis.” Lancet 369: 1090-1098 (2007)

Anxiety and Omega-3 Fatty Acids

Posted on January 23, 2012 by Dr. Barry Sears

Anxiety is one of most the common neurological disorders, but it also is one of the most difficult to understand. Simply stated, anxiety is an apprehension of the future, especially about an upcoming challenging task. This is normal. What is not normal is when the reaction is significantly out of proportion to what might be expected. Over the years, a number of specific terms, such as generalized anxiety disorder, panic disorder, phobia, social anxiety disorder, obsessive-compulsive disorder, post-traumatic stress disorder, and separation anxiety disorder have emerged in an attempt to better categorize general anxiety. Any way you describe anxiety, it is a big problem with nearly 20% of Americans suffering from it, thus making anxiety the largest neurological disorder in the United States (1).

If anxiety is worrying about the future, then it has a fellow traveler, depression. Depression can be viewed as an over-reaction about regret associated with past events. Not surprisingly, almost an equal number of Americans suffer from this condition. This leads to the question: Is there a linkage between the two conditions? I believe the answer is yes and it may be caused by radical changes in the American diet in the past 40 years. These changes have resulted in what I term the Perfect Nutritional Storm (2). The result is an increase in the levels of inflammation throughout the body and particularly in the brain.

The brain is incredibly sensitive to inflammation, not the type you can feel but the type of inflammation that is below the perception of pain. I term this cellular inflammation. What makes this type of inflammation so disruptive is that it causes a breakdown in signaling between cells. What causes cellular inflammation is an increase in the omega-6 fatty acid known as arachidonic acid (AA). From this fatty acid comes a wide range of inflammatory hormones known as eicosanoids that are the usual suspects when it comes to inflammation. This is why anti-inflammatory drugs (aspirin, non-steroid anti-inflammatories, COX-2 inhibitions and corticosteroids) all have a single mode of action—to inhibit the formation of these inflammatory eicosanoids. These drugs, however, can’t cross the blood-brain barrier that isolates the brain from a lot of noxious materials in the blood stream. So when the brain becomes inflamed, its only protection is adequate levels of anti-inflammatory omega-3 fatty acids. But what happens when the levels of omega-3 fatty acids are low in the brain? The answer is increased neuro-inflammation and continual disruption of signaling between nerves.

There are two omega-3 fatty acids in the brain. The first is called docosahexaenoic acid or DHA. This is primarily a structural component for the brain. The other is called eicosapentaenoic acid or EPA. This is the primary anti-inflammatory omega-3 fatty acid for the brain. So if the levels of EPA are low in the blood, they are going to be low in the brain. To further complicate the matter, the lifetime of EPA in the brain is very limited (3,4). This means you have to have a constant supply in the blood stream to keep neuro-inflammation under control.

It is known from work with uni-polar and bi-polar depressed patients, that high-dose fish oil rich in EPA has remarkable benefits (5,6). On the other hand, supplementing the diet with oils rich in DHA have virtually no effects (7).

Since anxiety has a significant co-morbidity with depression, the obvious question becomes is it possible that high levels of EPA can reduce anxiety? The answer appears to be yes (8), according to a study conducted in 2008 using substance abusers. It is known that increased anxiety is one of the primary reasons why substance abusers and alcoholics tend to relapse (9,10). When these patients were given a high dose of EPA (greater than 2 grams of EPA per day), there was a statistically significant reduction in anxiety compared to those receiving a placebo. More importantly, the degree of anxiety reduced was highly correlated to the decrease of the ratio of AA to EPA in the blood (8). In other studies with normal individuals without clinical depression or anxiety, increased intake of EPA improved their ability to handle stress and generated significant improvements in mood (11-13). It may be that depression and anxiety are simply two sides of the same coin of increased cellular inflammation in the brain. Even for “normal” individuals, high dose EPA seems to make them happier and better able to handle stress.

So let’s go back to an earlier question and ask about the dietary changes in the American diet that may be factors in the growing prevalence of both depression and anxiety. As I outline in my book Toxic Fat, it is probably due to a growing imbalance of AA and EPA in our diets (2). What causes AA to increase is a combination of increased consumption of vegetable oils rich in omega-6 fatty acids coupled with an increase in the consumption of refined carbohydrates that generate insulin. When excess omega-6 fatty acids interact with increased insulin, you get a surge of AA production. At the same time, our consumption of fish rich in EPA has decreased. The end result is an increasing AA/EPA ratio in the blood, which means a corresponding increase in the same AA/EPA ratio in the brain creating more cellular inflammation.

Cutting back vegetable oil and refined carbohydrate intake is difficult since they are now the most inexpensive source of calories. Not surprisingly, they are key ingredients for virtually every processed food product. So if changing your diet is too hard, then consider eating more fish to get adequate levels of EPA. Of course, the question is how much fish? If we use a daily intake level of 2 grams of EPA per day that was used the successful trials of using omega-3 fatty acids reduce anxiety, then this would translate into consuming 14 pounds of cod per day. If you prefer a more fatty fish like salmon, then you would only need about 2 pounds per day to get 2 grams of EPA. The Japanese are able to reach that level because they are the largest consumers of fish in the world. These are highly unlikely dietary changes for most Americans. However, it has been demonstrated that following a strict anti-inflammatory diet coupled with purified fish oil supplements can generate an AA/EPA ratio similar to that found in the Japanese population (11).

There is simply no easy way out of this problem created by the Perfect Nutritional Storm, which will only intensify with each succeeding generation due to the insidious effect of cellular inflammation on fetal programming in the womb. Unfortunately for most Americans this will require a dietary change of immense proportions. This probably means that Valium and other anti-anxiety medications are here to stay.

References

Kessler RC, Chiu WT, Demler O, Merikangas KR, and Walters EE. “Prevalence, severity, and comorbidity of 12-month DSM-IV disorders in the National Comorbidity Survey Replication”. Arch Gen Psychiatry 62:617–627 (2005)
Sears B. Toxic Fat. Thomas Nelson. Nashville, TN (2008)
Chen CT, Liu Z, Ouellet M, Calon F, and Bazinet RP. “Rapid beta-oxidation of eicosapentaenoic acid in mouse brain: an in situ study.” Prostaglandins Leukot Essent Fatty Acids 80:157-163 (2009)
Chen CT, Liu Z, and Bazinet RP. “Rapid de-esterification and loss of eicosapentaenoic acid from rat brain phospholipids: an intracerebroventricular study.” J Neurochem 116:363-373 (2011)
Nemets B, Stahl Z, and Belmaker RH. “Addition of omega-3 fatty acid to maintenance medication treatment for recurrent unipolar depressive disorder.” Am J Psychiatry 159:477-479 (2002)
Stoll AL, Severus WE, Freeman MP, Rueter S, Zboyan HA, Diamond E, Cress KK, and Marangell LB. “Omega 3 fatty acids in bipolar disorder: a preliminary double-blind, placebo-controlled trial.” Arch Gen Psychiatry 56:407-412 (1999)
Marangell LB, Martinez JM, Zboyan HA, Kertz B, Kim HF, and Puryear LJ. “A double-blind, placebo-controlled study of the omega-3 fatty acid docosahexaenoic acid in the treatment of major depression.” Am J Psychiatry 160:996-998 (2003)
Buydens-Branchey L, Branchey M, and Hibbeln JR. “Associations between increases in plasma n-3 polyunsaturated fatty acids following supplementation and decreases in anger and anxiety in substance abusers.” Prog Neuropsychopharmacol Biol Psychiatry 32:568-575 (2008)
Willinger U, Lenzinger E, Hornik K, Fischer G, Schonbeck G, Aschauer HN, and Meszaros K. “Anxiety as a predictor of relapse in detoxified alcohol-dependent patients.” Alcohol and Alcoholism 37:609-612 (2002)
Kushner MG, Abrams K, Thuras P, Hanson KL, Brekke M, and Sletten S. “Follow-up study of anxiety disorder and alcohol dependence in comorbid alcoholism treatment patients.” Alcohol Clin Exp Res 29:1432-1443 (2005)
Fontani G, Corradeschi F, Felici A, Alfatti F, Bugarini R, Fiaschi AI, Cerretani D, Montorfano G, Rizzo AM, and Berra B. “Blood profiles, body fat and mood state in healthy subjects on different diets supplemented with Omega-3 polyunsaturated fatty acids.” Eur J Clin Invest 35:499-507 (2005)
Fontani G, Corradeschi F, Felici A, Alfatti F, Migliorini S, and Lodi L. “Cognitive and physiological effects of Omega-3 polyunsaturated fatty acid supplementation in healthy subjects. “Eur J Clin Invest 35:691-699 (2005)
Kiecolt-Glaser JK, Belury MA, Andridge R, Malarkey WB, and Glaser R. “Omega-3 supplementation lowers inflammation and anxiety in medical students: A randomized controlled trial.” Brain Behav Immun 25:1725-1734 (2011)

Hard times are ahead

Posted on December 9, 2011 by Dr. Barry Sears

Last month was a red-letter month for the future of mankind as the world population passed 7 billion. Unfortunately, this fact dovetails with recent research that indicates it is likely that one-half of all Americans will be diabetic by 2050 (1).

The combination of these two trends does not bode well for the future. To begin with, how are we going to feed all these people? Most of the arable land on the planet is already under cultivation. Furthermore, urbanization is destroying prime cropland at a rapid pace.

Added to these facts is that the diversity of most of the world’s calories is rapidly decreasing. Currently the five top sources of calories in the world are corn, soybeans, wheat, rice and potatoes (as well as its kissin’ cousin cassava, which is incredibly poor in protein and nutrients). The first two crops (corn and soy) are rich sources of omega-6 fatty acids. In addition, corn, wheat, and rice provide extremely high-glycemic carbohydrates that can be easily refined to last forever and make thus a wide variety of processed foods. (Potatoes and cassava tend to decompose rapidly and can’t be easily refined, except perhaps as potato chips). As a consequence, omega-6 fatty acids and refined carbohydrates are now the cheapest form of calories in the world. In fact, it is estimated that they are 400 times less expensive per calorie than fresh fruits and vegetables.

So how can you feed this growing population of more than 7 billion people? The answer is easy—produce even more refined carbohydrates and omega-6 fatty acids.

Unfortunately, feeding the growing population of the world with cheap omega-6 fatty acids and refined carbohydrates is exactly the best way to increase cellular inflammation and drive the development of diabetes (2). It is estimated that by 2050 diabetes will be the primary non-infectious disease on the planet. This is equally bad news as it is also the most expensive chronic disease to treat on a long-term basis.

Today, more than 26 percent of all Americans older than 65 has diabetes. If the estimates of increased diabetes are correct (1), then it is likely that the number of Americans older than 65 in 2050 with diabetes may be greater than 50 percent. The current level of diabetes is the primary reason why our health-care expenses are spiraling out of control. If you double number of older Americans with diabetes by 2050, there is no way the current health-care system, as we know it can possibly survive. Add to the fact that once you have diabetes, you are 2-4 times more likely to develop heart disease and Alzheimer’s. It is not a very pleasant picture of the future of health care in America.

What can you do about it? On a global basis, not much unless you would like to see an apocalyptic event that reduces the population from 7 billion to a more manageable 1-2 billion individuals. Of course, this is highly unlikely. However, on the individual basis there is a lot you can do to protect yourself in the future. Simply take control of your future by focusing on managing cellular inflammation for a lifetime by following an anti-inflammatory diet. This may be your only real health security in times of increasing demands on the planet’s resources to produce food. There is no question that we have other troubles brewing like climate change, decreasing water supplies, and decreasing cheap energy, all of which will also impact the cost of food, driving more individuals toward inexpensive sources of calories no matter what the health consequences. But the rise of diabetes will occur first.

Old folks like myself will probably be OK, but the future generations will take the brunt of trouble brewing ahead.

References

Boyle JP , Thompson TJ, Gregg EW, Barker LE, and Williamson DF. “Projection of the year 2050 burden of diabetes in the US adult population: dynamic modeling of incidence, mortality, and prediabetes prevalence.” Population Health Metrics 8:29 (2010)
Sears B. “Toxic Fat.” Thomas Nelson. Nashville, TN (2008)

“Biggest Loser” or best Zoner?

Posted on November 21, 2011 by Dr. Barry Sears

A few weeks ago I spoke at the American Society of Bariatric Physicians. Later in the day I heard an interesting lecture from the lead dietician for the TV series “The Biggest Loser”. In this lecture, she disclosed all the keys for successful weight loss in the individuals on the show.

The first was incredibly careful screening just like you would do for a clinical trial. This is to make sure you have incredibly motivated people, who aren’t depressed or have other existing medical conditions, such as heart disease. In other words, you stack the deck. Considering that after the first pilot show in 2004, there were 225,000 applications for the 2005 series, there is no problem in recruiting motivated people. Just to make sure the motivation is maintained, the contestants get paid while they are on the show in addition to the big payoff for the winner at the end of the series.

Next contestants are isolated in a “camp”. Consider this to be like a metabolic ward where they only have access to good food for the next 10 to 16 weeks. This means no white carbohydrates and no artificial sweeteners other than stevia and all the meals made for them.

According to the speaker, the real secret is that they are fed a Zonelike Diet with 45 percent of the calories coming carbohydrates (primarily non-starchy vegetables and fruits) with a very limited amount of whole grains, 30 percent of the calories from low-fat protein, and 25 percent from good fats, such as olive oil or nuts. The typical calorie intake for the females is 1,200 to 1,600 and for the males about 1,800-2,400. The typical 300-pound contestant will consume about 1,750 calories per day. Finally, you spread the balanced calories over three meals and two snacks during the day.

Of course, you never see the contestants eating their Zone meals and snacks or the dietician discussing nutrition with them because that makes for boring TV. So most of the time you see them being yelled at by their trainers. That makes for exciting TV. In fact. the more tears they shed by being intimidated, the better the ratings.

So what happens to them after they leave the show, no longer get paid, and are surrounded by their favorite foods? About 50 percent regain the lost weight. But the other 50 percent have found out that the Zone Diet isn’t that hard, and now they have a clear dietary plan for a lifetime without being yelled at by drill sergeant-like trainers.

Eat Less, Get Hungry

Posted on August 10, 2011 by Dr. Barry Sears

Telling an obese person simply to eat less rarely succeeds. Is it because they are weak-willed individuals or is there something more complex going on? New research indicates the latter. A new article in Cell Metabolism showed that during extreme calorie restriction, the levels of fatty acids begin to rapidly rise in the blood as the body begins breaking down stored fat for energy. These newly released fatty acids from the fat cells can then enter into the brain (the hypothalamus to be exact) and cause the self-digestion of cells in the hunger neurons (1). This self-digestion of the cells in the hunger neurons produces a rise in the very powerful hunger hormone (AgRP) from the same bundle of neurons. Not surprisingly, the urge to eat becomes almost overpowering. This begins to explain why very low calorie diets can cause rapid weight loss, but are rarely successful in keeping the weight off.

This is why very low calorie diets that promise quick weight loss invariably cause the rapid release of stored fatty acids that promotes constant hunger. This is clearly not a sustainable way to maintain long-term weight management.

Of course the question might be whether it is all fatty acids or just one that causes the problem of cellular death in the hunger neurons? I believe the answer comes back to the usual suspect, arachidonic acid (2). It has been known for 20 years that when you put obese individuals on a very low calorie diet there is a rapid increase in the levels of arachidonic acid levels in the blood (3). Arachidonic acid can easily cross the blood brain barrier and enter into the hypothalamus. Since arachidonic acid is a powerful promoter of cell death (4), increased concentrations inside the hypothalamus may be the primary accelerator of the death of the hunger neurons. Increased levels of arachidionic acid in the blood are also the underlying cause of insulin resistance because of its effect on the generation of cellular inflammation (2). So as you build up the levels of stored arachidonic acid in the fat cells, caused by the Perfect Nutritional Storm (2), you are almost ensuring constant hunger when you try to lose weight quickly by following very low calorie diets. To make matters even worse, as arachidonic acid levels also build up in the brain increasing the production of endocannabinoids (5). These are the hormones that give you the continual munchies (they are related to the active ingredient in marijuana).

So is there any good news in all of this research? Yes as long as you develop a lifetime dietary strategy for reducing arachidonic acid and the cellular inflammation it causes as well as following a reasonable low calorie diet that supplies adequate levels of fat to moderate the release of stored fatty acids from the fat cells. It means following an anti-inflammatory diet with adequate protein using low-glycemic load carbohydrates and fats very low in omega-6 fatty acids, but adequate in monounsaturated and omega-3 fats.

That’s why you never want to start any type of weight loss program without adding omega-3 fatty acids to counteract the released of stored arachidonic acid from the fat cells. Not only will these omega-3 fatty acids reduce the degradation of the hunger neurons thereby reducing the release of powerful hunger hormones during calorie restriction, but they will also inhibit the release of endocannabinoids in the brain (6). The combination of the two events will ensure weight loss without hunger and that’s sustainable.

References

Kaushik S,Rodriguez-Navarro JA, Arias E, Kiffin R, Sahu S, Schwartz GJ, Cuervo AM, and Singh R. “Autophagy in hypothalamic AgRP neurons regulates food intake and energy balance.” Cell Metabolism 14: 173-183 (2011)
Sears B. Toxic Fat. Thomas Nelson. Nashville, TN (2008)
Phinney SD, Davis PG, Johnson SB, and Holman RT. “Obesity and weight loss alter serum polyunsaturated lipids in humans.” Amer J Clin Nutr 53: 831-838 (1991)
Pompeia C, Lima T, and Curi R. “Arachidonic acid cytotoxicity: can arachidonic acid be a physiological mediator of cell death?” Cell Biochemistry and Function 21:97-104 (2003)
Kim J, Li Y, and Watkins BA. “Endocannabinoid signaling and energy metabolism: A target for dietary intervention.” Nutrition 27: 624-632 (2011)
Oda E. “n-3 Fatty acids and the endocannabinoid system.” Am J Clin Nutr 85: 919 (2007)

Nothing contained in this blog is intended to be instructional for medial diagnosis or treatment. If you have a medical concern or issue, please consult your personal physician immediately.

Pass the salt please?

Posted on July 20, 2011 by Dr. Barry Sears

One of the great “truths” in cardiovascular medicine is that to prevent stroke and cardiovascular death you reduce your salt intake. But is it true? A new analysis of the existing literature from the Cochrane Library indicates this may not be the case (1). Analyzing a great number of published studies, researchers came to the conclusion that there is no strong evidence to support the idea that salt restriction reduces cardiovascular disease or all-cause mortality in people with either normal or increased blood pressure. Furthermore, they found that while reducing salt intake did decrease blood pressure, it also increased the risk of all-cause death in people with existing congestive heart failure.

If that wasn’t enough, an article in the May 4 issue of the Journal of the American Heart Association found that low salt increased the risk of death from heart attacks and stokes, while not reducing blood pressure (2). This study was done with middle-aged Europeans and followed them for nearly eight years. During this time, the less salt they consumed, the greater the number who died of heart disease.

Needless to say, the American Heart Association (the same people who recommend eating lots of omega-6 fats) was enraged, similar to the Wizard of Oz telling Dorothy to ignore the man behind the curtain.

So why might restriction of salt consumption cause increased heart attacks? The reason may be due to increased insulin resistance induced by salt restriction (3). Insulin resistance increases insulin levels, and if that is combined with increased consumption of omega-6 fatty acids (remember the American Heart Association), you now have a sure-fire prescription to produce more arachidonic acid. It’s the inflammatory eicosanoids derived from arachidionic acid that would cause inflammation in the arterial wall leading to a heart attack.

This is not to say that some people are not salt-sensitive (African-Americans are particularly so), but I believe the problem is more a matter of balance. You need some sodium, but you also need potassium to balance it. This is confirmed by a recent study from Harvard Medical School that demonstrates that the higher the sodium-to-potassium ratio in the blood, the greater the likelihood of cardiovascular mortality (4). The relationship for increased death was significantly greater for a high sodium-to-potassium level than simply the sodium level itself.

Getting sodium in your diet is easy (sprinkle salt on your food), but getting adequate levels of potassium means eating a lot of fruits and vegetables. So rather than restricting salt intake or taking drugs (i.e. diuretics) to reduce the levels of sodium in the body, think about eating more fruits and vegetables if your goal is to reduce the likelihood of a heart attack. Oh, yes, also ignore the advice of American Heart Association and take more omega-3 and less omega-6 fatty acids.

References

Taylor, RS, Ashton KE, Moxham T, Hooper L and Ebrahim S. “Reduced dietary salt for the prevention of cardiovascular disease.” Cochrane Database of Systematic Reviews DOI: 10.1002/14651858.CD009217 (2011)
Stolarz-Skrzypek K, Kuznetsova T, Thijs L, Tikhonoff V, Seidlerova J, Richart T, Jin Y, Olszanecka A, Malyutina S, Casiglia E, Filipovsky J, Kawecka-Jaszcz K, Nikitin Y, and Staessen JA. “Fatal and nonfatal outcomes, incidence of hypertension, and blood pressure changes in relation to urinary sodium excretion.” JAMA 305: 1777-1785 (2011)
Alderman MH. “Evidence relating dietary sodium to cardiovascular disease.” J Am Coll Nutr 25: 256S-261S (2006)
Yang Q, Liu T, Kuklina EV, Flanders WD, Hong Y, Gillespie C, Chang M-H, Gwinn M, Dowling N, Khoury MJ, and Hu FB. “Sodium and potassium intake and morality among US adults.” Arch Intern Med 171: 1183-1191 (2011)

Nothing contained in this blog is intended to be instructional for medial diagnosis or treatment. If you have a medical concern or issue, please consult your personal physician immediately.

Obesity continues to climb

Posted on July 18, 2011 by Dr. Barry Sears

Last week the Robert Wood Johnson Foundation reported that more than 12 states now have adult obesity rates greater than 30 percent, and that one in three children are either overweight or obese. However, 16 years ago, no state in the United States had an adult obesity rate greater than 20 percent. So in less than a generation, adult obesity has skyrocketed. Yet at the same time, according to the Centers for Disease Control, the percentage of overweight people has remained fairly constant since 1960, while the percentage of obese individuals has increased significantly since 1980. What this suggests is that there is a genetic component that can be activated in those individuals predisposed to gain weight. Once activated, accumulation of excess fat accelerates.

I feel the driving force between this activation of genetic factors is the increasing inflammatory nature of the American diet. We know that it is elevated insulin levels that make us fat and keep us fat. But what really causes insulin to become elevated in the first place? The simple explanation is that it comes from eating excess carbohydrates. However, that is too simplistic an explanation since one-third of adult Americans who are thin are also eating excess carbohydrates.

A more comprehensive answer is it’s insulin resistance that causes elevated insulin levels. Insulin resistance is a consequence of disturbances in the body’s insulin-signaling pathways in the cell caused by cellular inflammation. My most recent book, “Toxic Fat,” goes into great detail on this subject (1). But simply stated, the more cellular inflammation you have in your cells, the greater the likelihood of insulin resistance. And if you are genetically prone to gain weight, increasing insulin resistance will really pack on the extra fat. More insidious is that insulin resistance also creates a “fat trap” through which incoming dietary calories are trapped in your fat cells and can’t be released to provide the necessary energy the body needs. This means you are constantly hungry.

If you are surrounded by cheap processed foods (rich in omega-6 fatty acids and refined carbohydrates), then you are going to quench that hunger with those foods that increase cellular inflammation to even greater levels. The end result is an increasing rise of obesity.

But the fastest growing segment of the overweight and obese population is not adults, but children under the age of 5, with 20 percent now either overweight or obese before entering kindergarten (2). You can’t blame school lunches for this because they are not in school yet. What you can blame is epigenetics (3). This is how the metabolic future of the child can be greatly determined in the womb by the inflammatory nature of the mother’s diet. When these children are born, their altered genetics make them sitting targets for a world full of inflammatory food. Unless you change the foundation of the food supply to become more anti-inflammatory (less omega-6 fatty acids and a lower glycemic load), then the future for these children is incredibly bleak.

References

Sears B. “Toxic Fat.” Thomas Nelson. Nashville, TN (2008)
Kim J, Peterson KE, Scanlon KS, Fitzmaurice GM, Must A, Oken E, Rifas-Shiman SL, Rich-Edwards JW, and Gillman MW. “Trends in overweight from 1980 through 2001 among preschool-aged children enrolled in a health maintenance organization. Obesity 14: 1107-1112 (2006)
Lustig RH editor. “Obesity Before Birth.” Springer. New York (2011)

Nothing contained in this blog is intended to be instructional for medial diagnosis or treatment. If you have a medical concern or issue, please consult your personal physician immediately.

Zone diet validation studies

Posted on July 8, 2011 by Dr. Barry Sears

Weight Loss

Any diet that restricts calories will result in equivalent weight loss. However, the same doesn’t hold true as to what the source of that weight loss is. Weight loss from either dehydration (such as ketogenic diets) or cannibalization of muscle and organ mass (such as low-protein diets) has no health benefits. Only when the weight loss source is from stored fat do you gain any health benefits. Here the Zone diet has been shown to be superior to all other diets in burning fat faster (1-4). It has been demonstrated that if a person has a high initial insulin response to a glucose challenge, then the Zone diet is also superior in weight loss (5,6). A recent study from the New England Journal of Medicine indicates that a diet composition similar to the Zone diet is superior to other compositions in preventing the regain of lost weight (7). This is probably caused by the increased satiety induced by the Zone diet compared to other diets (1,8,9).

Reduction of cellular inflammation

There is total agreement in the research literature that the Zone diet is superior in reducing cellular inflammation (10-12). Since cellular inflammation is the driving force for chronic disease, then this should be the ultimate goal of any diet. Call me crazy for thinking otherwise.

Heart disease

It is ironic that the Ornish diet is still considered one of the best diets for heart disease, since the published data indicates that twice as many people had fatal heart attacks on the Ornish diet compared to a control diet (13). This is definitely the case of don’t confuse me with the facts. On the other hand, diets with the same balance of protein, carbohydrate and fat as the Zone diet has have been shown to be superior in reducing cardiovascular risk factors, such as cholesterol and fasting insulin (14,15).

Diabetes

The first publication validating the benefits of the Zone diet in treating diabetes appeared in 1998 (16). Since that time there have been several other studies indicating the superiority of the Zone diet composition for reducing blood glucose levels (17-20). In 2005, the Joslin Diabetes Research Center at Harvard Medical School announced its new dietary guidelines for treating obesity and diabetes. These dietary guidelines were essentially identical to the Zone diet. Studies done at the Joslin Diabetes Research Center following those dietary guidelines confirm the efficacy of the Zone diet to reduce diabetic risk factors (21). If the Zone diet isn’t recommended for individuals with diabetes, then someone should tell Harvard.

Ease of use

The Zone diet simply requires balancing one-third of your plate with low-fat protein with the other two-thirds coming from fruits and vegetables (i.e. colorful carbohydrates). Then you add a dash (that’s a small amount) of heart-healthy monounsaturated fats. The Zone diet is based on a bell-shaped curve balancing low-fat protein and low-glycemic-index carbohydrates, not a particular magic number. If you balance the plate as described above using your hand and your eye, it will approximate 40 percent of the calories as carbohydrates, 30 percent of calories as protein, and 30 percent of the calories as fat. Furthermore, it was found in a recent Stanford University study that the Zone diet provided greater amounts of micronutrients on a calorie-restricted program than any other diet (22).

Eventually all dietary theories have to be analyzed in the crucible of experimentation to determine their validity. So far in the past 13 years since I wrote my first book, my concepts of anti-inflammatory nutrition still seem to be at the cutting edge.

References

Skov AR, Toubro S, Ronn B, Holm L, and Astrup A. “Randomized trial on protein vs carbohydrate in ad libitum fat reduced diet for the treatment of obesity.” Int J Obes Relat Metab Disord 23: 528-536 (1999)
Layman DK, Boileau RA, Erickson DJ, Painter JE, Shiue H, Sather C, and Christou DD. “A reduced ratio of dietary carbohydrate to protein improves body composition and blood lipid profiles during weight loss in adult women.” J Nutr 133: 411-417 (2003)
Fontani G, Corradeschi F, Felici A, Alfatti F, Bugarini R, Fiaschi AI, Cerretani D, Montorfano G, Rizzo AM, and Berra B. “Blood profiles, body fat and mood state in healthy subjects on different diets supplemented with omega-3 polyunsaturated fatty acids.” Eur J Clin Invest 35: 499-507 (2005)
Layman DK, Evans EM, Erickson D, Seyler J, Weber J, Bagshaw D, Griel A, Psota T, and Kris-Etherton P. “A moderate-protein diet produces sustained weight loss and long-term changes in body composition and blood lipids in obese adults.” J Nutr 139: 514-521 (2009)
Ebbeling CB, Leidig MM, Feldman HA, Lovesky MM, and Ludwig DS. “Effects of a low-glycemic-load vs low-fat diet in obese young adults: a randomized trial.” JAMA 297: 2092-2102 (2007)
Pittas AG, Das SK, Hajduk CL, Golden J, Saltzman E, Stark PC, Greenberg AS, and Roberts SB. “A low-glycemic-load diet facilitates greater weight loss in overweight adults with high insulin secretion but not in overweight adults with low insulin secretion in the CALERIE Trial.” Diabetes Care 28: 2939-2941 (2005)
Larsen TM, Dalskov SM, van Baak M, Jebb SA, Papadaki A, Pfeiffer AF, Martinez JA, Handjieva-Darlenska T, Kunesova M, Pihlsgard M, Stender S, Holst C, Saris WH, and Astrup A. “Diets with high or low protein content and glycemic index for weight-loss maintenance.” N Engl J Med 363: 2102-2113 (2010)
Ludwig DS, Majzoub JA, Al-Zahrani A, Dallal GE, Blanco I, Roberts SB, Agus MS, Swain JF, Larson CL, and Eckert EA. “Dietary high-glycemic-index foods, overeating, and obesity.” Pediatrics 103: E26 (1999)
Agus MS, Swain JF, Larson CL, Eckert EA, and Ludwig DS. “Dietary composition and physiologic adaptations to energy restriction.” Am J Clin Nutr 71: 901-907 (2000)
Pereira MA, Swain J, Goldfine AB, Rifai N, and Ludwig DS. “Effects of a low-glycemic-load diet on resting energy expenditure and heart disease risk factors during weight loss.” JAMA 292: 2482-2490 (2004)
Pittas AG, Roberts SB, Das SK, Gilhooly CH, Saltzman E, Golden J, Stark PC, and Greenberg AS. “The effects of the dietary glycemic load on type 2 diabetes risk factors during weight loss.” Obesity 14: 2200-2209 (2006)
Johnston CS, Tjonn SL, Swan PD, White A, Hutchins H, and Sears B. “Ketogenic low-carbohydrate diets have no metabolic advantage over nonketogenic low-carbohydrate diets.” Am J Clin Nutr 83: 1055-1061 (2006)
Ornish D, Scherwitz LW, Billings JH, Brown SE, Gould KL, Merritt TA, Sparler S, Armstrong WT, Ports TA, Kirkeeide RL, Hogeboom C, and Brand RJ, “Intensive lifestyle changes for reversal of coronary heart disease.” JAMA 280: 2001-2007 (1998)
Wolfe BM and Piche LA. “Replacement of carbohydrate by protein in a conventional-fat diet reduces cholesterol and triglyceride concentrations in healthy normolipidemic subjects.” Clin Invest Med 22: 140-1488 (1999)
Dumesnil JG, Turgeon J, Tremblay A, Poirier P, Gilbert M, Gagnon L, St-Pierre S, Garneau C, Lemieux I, Pascot A, Bergeron J, and Despres JP. “Effect of a low-glycaemic index, low-fat, high-protein diet on the atherogenic metabolic risk profile of abdominally obese men.” Br J Nutr 86:557-568 (2001)
Markovic TP, Campbell LV, Balasubramanian S, Jenkins AB, Fleury AC, Simons LA, and Chisholm DJ. “Beneficial effect on average lipid levels from energy restriction and fat loss in obese individuals with or without type 2 diabetes.” Diabetes Care 21: 695-700 (1998)
Layman DK, Shiue H, Sather C, Erickson DJ, and Baum J. “Increased dietary protein modifies glucose and insulin homeostasis in adult women during weight loss.” J Nutr 133: 405-410 (2003)
Gannon MC, Nuttall FQ, Saeed A, Jordan K, and Hoover H. “An increase in dietary protein improves the blood glucose response in persons with type 2 diabetes.” Am J Clin Nutr 78: 734-741 (2003)
Nuttall FQ, Gannon MC, Saeed A, Jordan K, and Hoover H. “The metabolic response of subjects with type 2 diabetes to a high-protein, weight-maintenance diet.” J Clin Endocrinol Metab 2003 88: 3577-3583 (2003)
Gannon MC and Nuttall FQ. “Control of blood glucose in type 2 diabetes without weight loss by modification of diet composition.” Nutr Metab (Lond) 3: 16 (2006)
Hamdy O and Carver C. “The Why WAIT program: improving clinical outcomes through weight management in type 2 diabetes.” Curr Diab Rep 8: 413-420 (2008)
Gardner CD, Kim S, Bersamin A, Dopler-Nelson M, Otten J, Oelrich B, and Cherin R. “Micronutrient quality of weight-loss diets that focus on macronutrients: results from the A TO Z study.” Am J Clin Nutr 92: 304-312 (2010)

Nothing contained in this blog is intended to be instructional for medial diagnosis or treatment. If you have a medical concern or issue, please consult your personal physician immediately.