Nutrition

April 7, 2010

A Diet for Your Genotype?

If you’ve followed my teachings over the years, you’ll know that I believe in taking an individualized approach to nutrition. Simply stated, there is no one diet that is best for everybody. This view is not simply a personal opinion based on anecdotal experience; it’s backed up by a significant amount of research. Studies consistently show that people respond differently to different macronutrient profiles. Here’s an example. A study by Tay and colleagues reported that LDL (i.e. the “bad” cholesterol) levels remained unchanged after subjects consumed a low carb diet over 24 weeks. However, a closer look at the individual responses of participants in the study paints a vastly different picture. Almost 60% of low carb dieters actually showed a reduction in LDL while 24% showed an increase of at least 10%! Such widespread discrepancies can only be attributed to differences in genotype (i.e. the genetic makeup of an individual).

Now, recent research reveals that we may be closer to having an effective tool in customizing diets based on individual response. Data presented at the American Heart Association’s Nutrition, Physical Activity and Metabolism Conference showed that examining the activity of genes involved in fat metabolism can help predict what type of diet is best for a particular person. The researchers used a cheek swab to obtain genetic info on three genes–fatty acid binding protein 2, peroxisome proliferator- activated receptor gamma, and beta 2 adrenergic receptor–then sought to determine response to various diets (i.e. high-carb, low-carb, etc). The verdict? The genes studied had an extremely high correlation as to what diet worked best for the individuals, with those assigned to a the proper diet for their genotype losing up to three times as much weight after a year compared to those who were not assigned to a genotype-appropriate diet.

Now before we get too caught up in numbers, a few things to keep in mind. First, this was just an abstract and the data have not yet been published in a peer reviewed publication. Hence, results need to be interpreted with caution. Second, several of the researchers have a financial interest in the kit used to collect and interpret the info, which has the potential to introduce bias into results. That said, the research was carried out at a very prestigious university (Stanford) and the theoretical basis behind the approach is certainly sound. It will be interesting to see how this plays out, but it represents a potentially exciting development in nutritional science that has important future implications.

In the meantime, the best advice is to experiment with different macronutrient profiles and see how your body responds. A little trial-and-error goes a long way to optimizing a dietary approach that works best for you.

Stay Fit!

Brad

Tay J, Brinkworth GD, Noakes M, Keogh J, Clifton PM. (2008). Metabolic effects of weight loss on a very-low-carbohydrate diet compared with an isocaloric high-carbohydrate diet in abdominally obese subjects. J Am Coll Cardiol. 1;51(1):59-67.