Key to weight loss: Diet, genes or both?

  Fruit fly (Flickr / Photo by Zac Declerck)

No diet works for everyone. Some people lose weight easily on a low-carb, high fat Atkins-type diet, while others do well on a low fat diet. Now there is new science to help understand why some diets work for you and others just don’t.

According to research published in the July 2010 issue of GENETICS, there may be a genetic cause for dieting success and failure. Using fruit flies, researchers from the Department of Genetics at North Carolina State University found that the interaction of genes with diet, rather than diet alone, is the main cause of variation in body weight. This helps explain why some diets work better for some people, and suggests that diets should be tailored to an individual’s genes.

The scientists studied 146 different genetic lines of fruit flies that were fed four different diets (nutritionally balanced, low calorie, high sugar, and high fat). Flies in some of the genetic lines were highly sensitive to their diets, as reflected by changes in body weight, while flies of other lines showed no change in weight across diets. The scientists were able to ascertain what portion of the total variation in the metabolic traits was determined by genetics alone, by diet alone, or by the interaction between genes and diet. Results showed that diet alone made a small contribution to the total variation, while genes and interactions of genes with diet made very large contributions.

The results suggest that some individuals can benefit from altering their dietary habits, while the same changes for others will have virtually no effect. “There is no one-size-fits all solution to the diseases of obesity and type-2 diabetes,” said Laura K. Reed, Ph.D, the lead investigator in the work. According to Reed, each person has a unique set of genetic and environmental factors contributing to metabolic health, which means that the obesity epidemic is a complex problem that may require a different solution for each individual.

The idea that one diet won’t work for everyone is not news and in fact, is the basic tenet of Integrative Nutrition, the dietary program that attempts to help individuals find the most effective nutrition and lifestyle habits for their unique life. And there is no need to wait for a genetic analysis. You can listen to your body and it will tell you what works and what doesn’t. The trick is finding the diet that works for you and maximizes your energy and weight management.

However, the government and health agencies are notorious for advocating one universal way of eating for the general population. This led to the disastrous low-fat food pyramid that has contributed to the expanding national waistline.

There is no one right way to eat. Listen to your own body for the best diet advice.