The secret to weight loss isn’t a fancy DNA test or calorie calculator

The produce section is the key to health and wellness.
The produce section is the key to health and wellness.
Image: Reuters/Carlo Allegri
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In recent decades, as obesity and its associated maladies like heart disease and cancer have become a global epidemic, a cottage industry has arose to hawk supposedly clear paths for people aiming to shed excess weight. These have included dieting fads (paywall) like intense calorie counting and paleo eating that rapidly go in and out of fashion, and even DNA testing kits that promise a more precise way to build a healthy, personalized dieting regimen.

But according to new research, none of those single methods are as effective as they might purport. In a three-year, randomized study of 609 overweight adults, researchers compared weight change after participants spent 12 months on either a low-fat or low-carb diet. They then took those results and analyzed whether there was any connection to a person’s genotype pattern.

They found no significant difference between the two diets, according to the study published this week (Feb. 20) in the Journal of the American Medical Association. They also found no relationship between weight fluctuation and a participant’s DNA testing. This suggests there is no single strategy for losing weight, at least not one that works for a whole population of people—and also, that your genetic makeup isn’t going to determine the right dieting regime for you. That runs counter to many of the marketing campaigns currently in vogue in the dieting world.

As part of the study, dietitians interacted with the participants in 22 diet-specific small group sessions. Those sessions helped advise participants how to achieve the lowest fat or carbohydrate diets, by eating nutrient-dense meals that were also minimally-processed. The diets promoted eating vegetables and whole foods and never set specific numeric calorie targets for people to hit.

As the study participants attempted to implement their new diets over a three-year period, the researchers monitored their weight fluctuations and insulin levels. In general, people in the study lost weight. The study attributes that largely to the fact that the diets cut out the sorts of processed foods that include a lot of sugar and refined grains.

Companies manufacturing much of the world’s foods have long obsessed making products convenient to eat. But processed foods, ranging from the clearly unhealthy (potato chips and sugary drinks) to option that seem fine but are not (like deli meats and packaged cereals), have been increasingly tied to weight gain and serious health risks like cancer.

In some ways, the study suggests that the best approach weight management is the most simple and time-tested: eat a balanced diet that prioritizes home cooking and eating fresh produce over microwavable meals and packaged foods. That’s also consistent with the latest recommendations laid out by the 2015 US Dietary Guidelines Advisory Committee and the federal government’s subsequent report.