Study: Low-Carb, Low-Fat Diet Produce Same Weight-Loss Results
You're about to go on a diet and you're debating the best approach. Then a common question rears its head: Is a low-carbohydrate diet or low-fat diet the best way to lose weight?
According to a new Stanford University School of Medicine study, neither is more or less effective; both help you shed weight in similar proportions.
Researchers focused on genetics and insulin for the study as well, working to determine if these factors would make either a low-carb diet or a low-fat diet more effective. The research appears in Tuesday's issue of the journal JAMA.
The study included 609 participants -- half men and half women, roughly -- all between 18 and 50 years old. The people were randomly split into groups following a low-carb or a low-fat diet and were told to maintain those diets for one year. Twenty percent didn't complete the study.
Participants had to reduce their fat or carbohydrate intake each day to only 20 grams in the first eight weeks, roughly the amount of each found in a handful of nuts or one-and-a-half slices of whole wheat bread. After this eight-week period, they could add five to 15 grams of fat or carbs back to their diet at a gradual pace.
"We made sure to tell everybody, regardless of which diet they were on, to go to the farmer's market, and don't buy processed convenience food crap. 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," Christopher Gardner, Stanford University professor of medicine and lead author of the study, said in a statement. "We wanted them to choose a low-fat or low-carb diet plan that they could potentially follow forever, rather than a diet that they'd drop when the study ended."
In addition to the dieting, participants underwent genome sequencing and a baseline insulin test. The genome sequencing gave scientists a way to check for gene patterns linked to making proteins that modify carbohydrate or fat metabolism, and the insulin test involved participants drinking a shot of glucose to test for insulin output.
People lost an average of 13 pounds at the end of the study whether on the low-fat or low-carb diet, though this varied between participants. Some lost as much as 60 pounds, for instance, while others actually gained 15 or 20 pounds. The research negated the study hypothesis, as there was no link between genotype pattern or insulin level and a likelihood of success for the respective diets researched.
Gardner says the most important takeaway from the study is that weight loss strategy for either diet is close to the same: eating less sugar and refined flour, and consuming a lot of vegetables.
"I feel like we owe it to Americans to be smarter than to just say 'eat less,'" Gardner continued in the statement. "I still think there is an opportunity to discover some personalization to it -- now we just need to work on tying the pieces together."
Such personalization can be found in diets from the U.S. News Best Diets rankings, like the No. 1 Best Diet for Weight Loss and No. 4 Best Diet Overall, the Weight Watchers Diet.
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David Oliver is a social media associate editor at U.S. News & World Report. Follow him on Twitter, connect with him on LinkedIn, or send him an email at doliver@usnews.com.
