Study under review: Effect of Low-Fat vs Low-Carbohydrate Diet on 12-Month Weight Loss in Overweight Adults and the Association With Genotype Pattern or Insulin Secretion: The DIETFITS Randomized Clinical Trial.
We tackled this breakout study in a recent blog post, Low-fat vs. low-carb? Major study concludes: it doesn’t matter for weight loss. If you have already read this, we go into even greater detail in this Study Deep Dives analysis (aka we went Full Nerd) and include previously unreleased Study Deep Dives exclusive Q&As with the lead author — Dr. Christopher Gardner. We also have an extended FAQ section where we tackle many common questions and misconceptions about the study. We also found a blog post from a man who recounted his experiences during this one-year trial (definitely worth a read), a Vox article interviewing four other participants, and a podcast interview with Dr. Gardner himself. Now, onto the analysis!
In free-living, long-term trials (longer or equal to 12 months), multiple studies have found that low-fat diets and low-carbohydrate diets result in small weight loss differences, when compared head-to-head. But there is one central limitation with many of these trials: adherence to the dietary intervention. Many participants start off strong in their assigned low-fat or low-carb diet, but by the end of the study, they have often returned to their usual pre-study eating habits.
Even though these studies report minimal between-group differences, individual weight changes within either dietary group can be wildly different: some participants losing 25.0 kilograms (55 pounds) while others gaining 5.0 kilograms (11 pounds).These results suggest that some diets may work better for certain individuals than for others. The reasons for these individual responses are not well understood. Emerging data indicate that insulin sensitivity or select genetic markers might help predict a person's success or failure on differing dietary interventions. The present study was designed to identify and investigate potential interactions between diet × genotype and diet × insulin secretion from participants who were actually adhering to their assigned diet.
Many long-term studies comparing low-fat and low-carb trials have yielded minimal between-group weight loss differences. However, individual weight changes within either group can vary tremendously. The study under review was designed to test whether select genetic markers or insulin production could predict weight loss success in participants assigned to either a low-fat or low-carb diet._
Other Articles in Issue #41 (March 2018)
Mini: How fiber helps with diabetes
A recent article in a major scientific journal sheds light on how exactly dietary fiber impacts glycemic control. We cover it briefly here.
Antioxidants and exercise: no pain, no gains?
Some people turn to antioxidants to help with delayed onset muscle soreness. This recent Cochrane review examines whether they're effective.
Can lutein and zeaxanthin improve the cognitive function of young adults?
A lot of studies focus on nutrition’s effects on the cognition of older adults. But that’s not the only population looking for a brain boost.
Can calcium and vitamin D prevent fractures in community-dwelling older adults?
While supplementation may prevent fractures in certain populations, this meta-analysis addresses the question of whether it’s effective for people who don’t live in an institution like a nursing home.
Mediating depression through the Mediterranean Diet
Diet can impact some aspects of mood. Can it make a dent in depression?
Mini: the ISSN’s position on nutrient timing
Want a quick summary of the International Society of Sports Nutrition's latest position stance on the impact of timing macro intake for athletes? We got you covered.
A berry tasty solution to cardiovascular disease risk factors
Berries are packed with nutrients and fiber, making them a great healthy food choice. But are they healthy enough to impact cardiovascular risk markers?