Research

Energy balance

Intermittent fasting (IF) significantly reduces body weight, BMI, fat mass, and triglycerides compared to regular diet in overweight/obese adults aged 40+ without metabolic disease, without causing significant loss of lean body mass.

If you are over 40 and overweight, trying intermittent fasting (like time-restricted eating or alternate-day fasting) can help you lose fat and weight without losing muscle, compared to just eating normally. Stick to a 2-6 week trial to see if it works for you.

GoodSupportsMEDIUM confidence
meta-analysis showed that body weight (MD: -2.05 kg; 95% CI (-3.84, -0.27); p < 0.001) were significantly lower in the experimental group than in the control group... No significant reduction in lean body mass (MD: -0.31 kg; 95% CI (-0.96, 0.34); p = 0.35)... IF had a reduction in body weight, BMI, fat mass, and TG in adults aged over 40 with obesity without metabolic disease compared to RD, and IF did not cause a significant decrease in lean body mass, which suggests healthy and effective fat loss.
Ke Yao et al. · The journal of nutrition health & aging · 2024

Why this rating

Meta-analysis of 9 RCTs, though heterogeneity was noted in some metrics and risk of bias was high due to lack of blinding.

Source

Effectiveness of an intermittent fasting diet versus regular diet on fat loss in overweight and obese middle-aged and elderly people without metabolic disease: a systematic review and meta-analysis of randomized controlled trials

Ke Yao et al. · The journal of nutrition health & aging · 2024

DOI 10.1016/j.jnha.2024.100165

Meta-analysis · 9 studiesCited 23×
Read the paper
DOI resolved against Crossref · corpus check 2026-06-10

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