Carbs, fat, DNA? Weight loss is finicky, new study shows

Feb 22, 2018, 01:01
Carbs, fat, DNA? Weight loss is finicky, new study shows

Lead study author Christopher Gardner, the director of nutrition studies at the Stanford Prevention Research Center, noted that the point of the study wasn't to compare a low-fat diet to a low-carb one to see which was best for weight loss, as many previous studies have done. (0.7 kg) - the difference within each diet group was more varied and more interesting, Gardner said.

Companies that develop gene-based diets told science news site STAT the genes Dr Gardner tested for aren't the only ones that can influence weight loss, and other personal info - such as blood types - are also important. Gardner found a person's genes (and other factors, like insulin levels) did not predict which diet would result in the most weight loss.

The 600 volunteers were randomly assigned to either a low-fat or low-processed-carbohydrate diet. He previously led a smaller study, in 2010, finding that overweight women whose genotype matched their diet lost 13 pounds in a year while those who were mismatched lost just over 4 pounds. In all, 241 participants on the low-fat diet and 238 individuals on the low-carb diet finished the study.

The study participants were not told to count calories or anything, but had to limit either their fat or carbohydrate intake.

More news: Today's natural disaster in England and Wales: Massive for British standards

After that they added back five to 15 grams of fat or carbs gradually, aiming to reach a balance they believed they could maintain for the rest of their lives.

Instead of imposing strict food or caloric restrictions, participants were asked to cut down to no more than 20 grams (0.7 ounces) of fat or carbs a day for the first two months. Halfway through the study, fat consumption was 50 and 87 grams per day, respectively, while carb consumption was 211 and 113 grams per day, a pattern that held for the full 12 months.

In diet studies, the average often doesn't tell the whole story.

"Also, we advised them to diet in a way that didn't make them feel hungry or deprived - otherwise it's hard to maintain the diet in the long run". Some whose genetic markers indicated a low-carb diet would work better for them did not lose significantly more or less weight on either kind of diet, and the same was true for low-fat dieters.

More news: Reuters report on Myanmar massacre brings calls for independent probe

Over the course of a year, researchers monitored participant progress, logging information about weight, body composition, baseline insulin levels and how many grams of fat or carbohydrate they consumed daily. At the end, both groups had lost about the same amount of weight, on average. One of the key focuses of the study was to understand how individual factors relate to weight loss and each participant's genome was examined at the start of the study. Researchers aren't sure why people react so differently, just that low-carb vs. low-fat doesn't explain it.

It didn't include very many people, however, so Gardner and colleagues recruited more volunteers and tried a more rigorous approach. Go for whole foods, whether that is a wheatberry salad or grass-fed beef.

Moving forward, he and his team will continue to analyse the data collected to uncover what is behind individual weight loss. "But let's cut to the chase: We didn't replicate [our previous] study, we didn't even come close". "I still think there is an opportunity to discover some personalisation to it [dieting] - now we just need to work on tying the pieces together".

More news: FireEye (FEYE) Given a $20.00 Price Target at Evercore ISI