Peer-reviewed study
Fasting outcomes still need protein and training context
The impact of intermittent fasting on body composition and cardiometabolic outcomes in overweight and obese adults: a systematic review and meta-analysis of randomized controlled trials
Kris Oddo, NASM-certified personal trainer, is the founder and head coach of Gains From Geebs (Geebs Coaching), a 1:1 online fitness coaching practice.
Quick answer
What this study found
For body composition, fasting should be judged by the whole plan: calories, protein, lifting performance, sleep, hunger, and consistency.
How strong is this kind of study?
- Reviews of many studiesThis study
- Controlled trials
- Observational
- Narrative reviews
Systematic review and meta-analysis of RCTs. Heavier plates are built from more studies, so they move less when the next one lands.
At a glance
What kind of study this is
Strongest evidence
This pools results from many separate studies, so it carries more weight than any single trial on its own.
- Design
- Systematic review and meta-analysis of RCTs
- Published
- 2025
- Journal
- Nutrition Journal
- Reference
- PMID 40731344
Honest limits
What this study does not prove.
Fasting alone does not protect lean mass; resistance training and adequate protein still do most of that work.
Kris's practical takeaway
Here's what to do with it.
For body composition, fasting should be judged by the whole plan: calories, protein, lifting performance, sleep, hunger, and consistency.
Ways to use it
Safe ways to apply it.
The window is not the whole diet
Fasting needs a muscle plan too
Judge a diet by whether you can follow it
Related questions
Questions this research helps answer.
Related guides and studies
Keep learning about nutrition.
FAQ
Quick questions
What is the practical takeaway from this study?
For body composition, fasting should be judged by the whole plan: calories, protein, lifting performance, sleep, hunger, and consistency.
What does this study not prove?
Fasting alone does not protect lean mass; resistance training and adequate protein still do most of that work.
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