While metabolic and genomic testing aren't good indicators of how efficiently a body loses weight, the researchers warned that in the future, there might be new research that'll bring up better predictors of which diets work best for a person. Another theory is that these diets are pretty boring and make eating less attractive. "We know weight loss is tough and sustained weight loss is even tougher".
Individual results after a year were quite varied - one person lost 60 pounds, while another gained 20 - but the average weight loss in each group was nearly identical: 11 pounds in the low-fat group, compared to 13 pounds in the low-carb group. "We really need to focus on that foundational diet, which is more vegetables, more whole foods, less added sugar and less refined grains". The low-carb group was advised to eat foods such as avocados, hard cheeses, vegetables, olive oil, salmon, nut butter, and grass-fed and pasture-raised animal foods.
People were remarkably compliant about following their assigned low-fat or low-carb diet. It may be that some people find low-fat or low-carb diets easier to stick to, because of personal preference.
"Over one year, the low-fat group lost 12 pounds on average", he tells EndocrineWeb, and "group following the low carb diet lost about 13 pounds". "In the context of these 2 common weight loss diet approaches, neither of the 2 hypothesised predisposing factors was helpful in identifying which diet was better for whom".
What kind of research was this? That was the case for 97 of the 180 people with the low-carb genotype.
"There is consistent evidence that calorie restriction benefits weight loss", Qi, who wasn't involved in the study, said by email. There was also no DNA/diet interaction for waist circumference, body mass index, or body fat percentage.
The group was composed of people between the ages of 18 and 50, and around six out of 10 were women. "There isn't any one diet that anyone has to follow". A spokeswoman for another leading DNA/diet company, Habit, said it agrees that DNA alone "isn't enough to develop personalized dietary recommendations" and that the company therefore factors in blood biomarkers and other information "when making personalized dietary recommendations".
Researchers at Stanford University found that overweight adults who followed a low-fat or low-carbohydrate diet tailored to their genetic predisposition and biological makeup weren't any more successful at shedding pounds than the groups that followed the same two diets, but without the customization for these predispositions.
'This study closes the door on some questions - but it opens the door to others. Those on genetically matched diets seemed to do better.
It's true that the researchers didn't emphasize calorie counting. Also, some people lost as much as 60 pounds and others gained 15 pounds - more evidence that genetic characteristics and diet type appeared to make no difference. "They suck", Gardner said.
"We were so excited and thought this would work. It's humbling, and just underlines the importance of replication" of tantalizing preliminary findings with larger, more rigorous studies.