Changing gene expression

I have often stated that the real power of the Zone Diet is to change gene expression, especially the expression of anti-inflammatory genes. What I never realized is how rapid gene expression could occur. Now, new research from Norway gives me the answer (1). It takes about 24 hours!

This pilot study is on the effect of diet on gene expression in healthy obese individuals. Interestingly, when the researchers calculated the estimated daily calorie requirements for these subjects necessary to maintain their weight, they were surprised that they were already eating 250 fewer calories per day than predicted to maintain their current weight. So much for the “fact” that obese individuals are fat because they eat more calories than they need to maintain their weight. In fact, this observation was confirmed in an earlier study in which the number of calories consumed by obese and lean individuals did not vary, but the obese individuals consumed fewer meals consisting of larger servings (2).

So what the Norwegian researchers did was simply maintain the same number of calories the subjects were already eating and change the macronutrient balance to be very close to the Zone Diet (30 percent carbohydrates, 30 percent protein, and 40 percent fat). Then the subjects consumed six meals containing about 460 calories evenly spaced throughout the day so that the total calories consumed at any one time was moderate. Just making those two simple dietary changes resulted in more than an eight-pound weight loss in 28 days. The levels of body fat didn’t change since the number of calories consumed was exactly the same as they were previously consuming. However, it appears that evenly spacing the meals and reducing the calorie size of the meals resulted in less insulin production and therefore less retained water.

Then they looked to see if they could find any changes in gene expression in both the fat cells and the blood with the dietary changes. Amazingly they found dramatic changes in only 24 hours. Of the 16,000 genes they could identify, about 60 percent remained unchanged in their expression, but 40 percent were either turned on (i.e., up-regulated) or turned down (i.e., down-regulated). Interestingly, the changes seen in the first 24 hours were held constant throughout the 28 days of the experiment.

Upon further analysis, the up-regulated genes corresponded to those that had anti-inflammatory properties, and the down-regulated genes were those associated with chronic disease conditions, such as diabetes and heart disease. Furthermore, since these changes in gene expression occurred within 24 hours of the dietary change, they could not be attributed to any change in body weight and fat loss.

Fortunately, I had the opportunity to have dinner with the lead author of the study to discuss her work while I was in Europe last week. She told me that she has expanded the number of subjects in several new trials, and the results remain the same. I also found out that she has been following my work for many years.

This type of study only confirms the power of genetic analysis to demonstrate how a highly structured diet with the correct macronutrient content can rapidly alter genetic expression and hence controls your future health. But the door swings both ways. An unbalanced diet will have just the opposite genetic effects. While I have always been impressed by the power of the Zone Diet, this new experimental data takes my respect for the Zone Diet to a new level of awe, even by me.


  1. Brattbakk H-R, Arbo I, Aagaard S, Lindseth I, de Soysa AK, Langaas M, Kulseng B, Lindberg, and Johansen B. “Balanced caloric macronutrient composition down regulates immunological gene expression in human blood cells-adipose tissue diverges.” OMICS 15: doi:1089/omi.2010.0124 (2011)
  2. Berg C, Lappas G, Wolk A, Strandhagen E, Toren K, Rosengren A, Rosengren A, Thelle D, and Lissner L. “Eating patterns and portion size associated with obesity in a Swedish population.” Appetite 52: 21-26 (2009)

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About Dr. Barry Sears

Dr. Barry Sears is a leading authority on the impact of the diet on hormonal response, genetic expression, and inflammation. A former research scientist at the Boston University School of Medicine and the Massachusetts Institute of Technology, Dr. Sears has dedicated his research efforts over the past 30 years to the study of lipids. He has published more than 30 scientific articles and holds 13 U.S. patents in the areas of intravenous drug delivery systems and hormonal regulation for the treatment of cardiovascular disease. He has also written 13 books, including the New York Times #1 best-seller "The Zone". These books have sold more than 5 million copies in the U.S. and have been translated into 22 different languages.