POUNDS LOST — Comparison of weight-loss diets with different compositions of fat, protein, and carbohydrates
In plain English
811 overweight adults were randomised to one of four reduced-calorie diets spanning the full range of fat, protein and carbohydrate ratios, then followed for two years. All four produced near-identical weight loss — about 4 kg at two years — with no advantage for any particular macronutrient mix. What predicted success was calorie reduction and session attendance, not whether the diet was low-fat or low-carb. It is the cleanest randomised evidence that, for weight loss, total energy matters far more than macronutrient composition.
Why it matters
Across four diets with very different fat/protein/carb ratios, weight loss was the same — calories, not macros, drove the result.
Informs: Weight Loss·Diabetes
Provenance
- Design
- Randomised controlled trial
- Sample size (n)
- 811
- Follow-up
- 2 years
- Peer-reviewed
- Yes
- Replications
- 2
- Funding
- Public / academic
- Funders
- US National Heart, Lung, and Blood Institute (NHLBI)
- Institutions
- Harvard T.H. Chan School of Public Health, Pennington Biomedical Research Center
decades.plus score
A transparent 0–100 weighted sum across six components. Higher scores reflect bigger, cleaner, more replicated work.
Caveats
Adherence drifted toward the middle: by two years the assigned diets had converged, so the trial arguably tested calorie restriction more than truly distinct macronutrient patterns. Average weight loss was modest and partly regained, underlining how hard long-term maintenance is regardless of diet type.
