If you're overweight and eat less fat for four weeks, you might lose more muscle than fat compared to someone who eats fewer carbs — even if both diets help you lose weight.
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In overweight adults, a low-fat diet implemented over four weeks is associated with a greater loss of lean mass relative to fat mass compared to a low-carbohydrate diet, indicating differential effects on body composition.
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If you're overweight and eat less fat for four weeks, you might lose more muscle than fat compared to someone who eats fewer carbs — even if both diets help you lose weight.
Evidence from Studies
No evidence studies found yet.
What Would Prove This
Per GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this claim, ordered from strongest to weakest.
Systematic Review of Low-Fat vs Low-Carbohydrate Diets on Body Composition in Overweight Adults Over Four Weeks
Meta-analysis of randomized controlled trials comparing low-fat and low-carbohydrate diets in overweight adults, with dual-energy X-ray absorptiometry (DXA) measurements of lean and fat mass at baseline and week 4.
Double-Blind Randomized Trial of Low-Fat vs Low-Carbohydrate Diet on Body Composition in Overweight Adults Over Four Weeks
Randomized, controlled, double-blind trial assigning overweight adults to either a low-fat or low-carbohydrate diet for four weeks, with body composition measured via DXA before and after intervention.
Prospective Cohort Study of Dietary Patterns and Body Composition Changes in Overweight Adults Over Four Weeks
Prospective cohort following overweight adults who self-select into low-fat or low-carbohydrate diets over four weeks, with serial DXA scans to compare lean and fat mass loss.
Cross-Sectional Analysis of Diet Type and Body Composition in Overweight Adults at Four-Week Mark
Single-time-point survey and DXA measurement of overweight adults who have been on either a low-fat or low-carbohydrate diet for approximately four weeks.
Case Report of Lean Mass Loss on Low-Fat Diet vs Low-Carb Diet in Two Overweight Adults Over Four Weeks
Detailed case reports of two overweight adults, one on low-fat and one on low-carb diet, with body composition tracking over four weeks.