DIETFITS — Effect of low-fat vs low-carbohydrate diet on 12-month weight loss
In plain English
609 adults were randomised to a healthy low-fat or a healthy low-carbohydrate diet — both emphasising whole, minimally processed foods with no calorie target — for twelve months. Average weight loss was essentially the same in both groups (about 5.3 kg vs 6.0 kg), and neither a person's insulin secretion nor their diet-related genotype predicted which approach worked better, debunking a popular personalisation theory. The lesson the authors drew was that food quality, not the fat-versus-carb axis, is what counts.
Why it matters
Healthy low-fat and healthy low-carb diets produced the same weight loss — and genes and insulin didn't predict who did better.
Informs: Weight Loss·Diabetes
Provenance
- Design
- Randomised controlled trial
- Sample size (n)
- 609
- Follow-up
- 1 years
- Peer-reviewed
- Yes
- Replications
- 1
- Funding
- Mixed (public + private/non-profit)
- Funders
- US National Institutes of Health, Nutrition Science Initiative, Stanford Clinical and Translational Science Award
- Institutions
- Stanford University School of Medicine
decades.plus score
A transparent 0–100 weighted sum across six components. Higher scores reflect bigger, cleaner, more replicated work.
Caveats
Both arms focused on whole foods and cutting added sugar and refined grains, so the trial does not test typical junk-food versions of either diet. Weight change varied enormously between individuals within each group, which a single average obscures, and the one-year horizon leaves long-term maintenance untested.
