If you're a middle-aged adult with extra weight, eating either a low-carb high-fat diet or a low-fat diet with fewer calories can help you keep your muscle while losing weight over about 4 months.
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In middle-aged adults with overweight or obesity, both low-carbohydrate high-fat diets and calorie-restricted low-fat diets are associated with the preservation of total body and appendicular lean mass over a 15-week period, suggesting that either dietary approach can support the maintenance of lean mass during weight loss in this population.
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If you're a middle-aged adult with extra weight, eating either a low-carb high-fat diet or a low-fat diet with fewer calories can help you keep your muscle while losing weight over about 4 months.
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 and Meta-Analysis of Randomized Controlled Trials Comparing Low-Carbohydrate High-Fat vs Calorie-Restricted Low-Fat Diets on Lean Mass Preservation in Middle-Aged Adults with Overweight or Obesity Over 15 Weeks
Systematic review of RCTs with meta-analysis, including only studies on middle-aged adults with overweight or obesity, comparing low-carb high-fat vs calorie-restricted low-fat diets over at least 15 weeks, with lean mass measured via DXA as primary outcome.
15-Week Double-Blind Randomized Trial of Low-Carbohydrate High-Fat vs Calorie-Restricted Low-Fat Diet on Lean Mass in Middle-Aged Adults with Obesity
Double-blind, parallel-group RCT with random assignment to low-carb high-fat or calorie-restricted low-fat diet for exactly 15 weeks, with DXA-measured lean mass as primary outcome, controlling for protein intake and physical activity.
Prospective Cohort Study of Dietary Patterns and Lean Mass Changes Over 15 Weeks in Middle-Aged Adults with Overweight or Obesity
Prospective cohort tracking middle-aged adults with overweight or obesity following either diet for 15 weeks, measuring lean mass at baseline and endpoint, adjusting for confounders like age, sex, baseline weight, and activity level.
Case-Control Study Comparing Dietary Histories of Middle-Aged Adults Who Preserved vs Lost Lean Mass Over 15 Weeks During Weight Loss
Retrospective comparison of dietary patterns in individuals who maintained lean mass versus those who lost it during 15-week weight loss, matched on age, sex, and BMI.
Cross-Sectional Analysis of Diet Type and Lean Mass in Middle-Aged Adults with Overweight or Obesity Currently on Low-Carb or Low-Fat Diets
Snapshot assessment of diet type and lean mass in a representative sample of middle-aged adults with overweight or obesity, stratified by diet duration and type.