There’s no doubt that obesity is a growing problem in America. In 1962, obesity affected 13 percent of Americans. By 2000, the percentage of obese Americans had grown to 31 percent. Today, almost 4 million people in the United States tip the scales at more than 300 pounds.
Rising obesity rates have prompted yo-yo dieters and public health officials alike to look for a fix. According to some researchers, the solution could lie within our bodies: our genes. In fact, researchers at Stanford University recently found that matching dieters to a specific type of diet based on their genetic makeup could significantly increase weight-loss success.
“If you look at average weight-loss statistics, average people lose only a few pounds with any weight-loss diet,” says Christopher D. Gardner, PhD, lead investigator for the study and director of nutrition studies at the Stanford Prevention Research Center. “But look inside the numbers and you find that some people do lose lots of weight and some fail completely. The difference could be explained by genetics.”
Research on Weight Loss and Genetics
“Genetics can tell us who is at risk for obesity, but that is not the big question for us,” Gardner says. “We want to know if genetics can tell us who is predisposed to do better on a low-fat diet and who will do better on a low-carbohydrate diet.”
“Your genes determine how your body responds to insulin,” he explains, “and that has a lot to do with weight loss.” If you are insulin-resistant, your body has trouble with carbohydrates, so you may do better with a low-carbohydrate diet. If you are insulin-sensitive, you may do better on a low-fat diet. If you are in the middle, a balanced diet should work best.
Research on this comes from a study in which participants were placed on various low-fat or low-carbohydrate diets. Here is what the researchers found when they matched the genotypes up with the diet results:
- Women who were genotype-matched to the diet they were assigned lost 5.3 percent of their body weight, compared with 2.3 percent for the unmatched group.
- Women who were properly matched to the lowest-carbohydrate (Atkins) and the lowest-fat (Ornish) diets lost 6.8 percent of their body weight, compared with 1.4 percent for the unmatched group.
What Obesity Gene Research Means for You
Interleukin Genetics, the company that did the DNA testing for the study, already has a home genetic test that you can send away for. It can tell you what your weight-loss genetics are and will suggest a diet and exercise program for you.
This could be valuable information if you are struggling with weight loss. However, there is more to weight loss than genes. “Sometimes our technology gets a little bit ahead of our actual ability to use it,” says Myra J. Wick, MD, PhD, an assistant professor of medical genetics at the Mayo Clinic.
Dr. Wick cautions that genes are only one part of the picture — how your environment affects those genes is equally important. Scientists call this effect “epigenetics.” When it comes to weight loss, that means that the choices you make are as important as your genetic makeup.
“In the next five to 10 years there will be big breakthroughs in how we use genes to treat all kinds of conditions, but we are not quite there yet,” Wick says. “There are lots of testing kits out there. Geneticists sometimes refer to home testing as ‘recreational genetics.’ [These kits] can give you some valuable information, but don’t forget about exercise and other lifestyle choices.”
After all, back when just 13 percent of Americans were obese, they had the same genes. Research has found that healthy eating and regular exercise can counter a predisposition for obesity. In fact, one recent study says that a single brisk daily walk could be enough to override the “obesity gene.”
“We are not a slave to our genes,” Gardner says. “You can override your genetics with healthy choices like eating less and exercising more.”