Treatments and supplements · Caloric restriction and fasting

Does eating less help me live longer and healthier?

What we can tell you today: how thoroughly this has been studied.

Thoroughly studied

16 studies, of which 11 bring together the results of several trials in people. This is as strong as evidence gets.

5 Repeated evidence 11 studies

4 Large controlled trial 5 studies

This says how thoroughly something has been studied — not whether it works for you. What each study actually found is in the study itself, and in the plain-language write-ups we are adding.

Appears under: Weight loss and GLP-1 · Living longer in good health

The studies

5 Repeated evidence Intermittent fasting strategies and their effects on body weight and other cardiometabolic risk factors: systematic review and network meta-analysis of randomised clinical trials.
2025 · BMJ (Clinical research ed.) · 6,582 participants · manufacturer helped fund this
5 Repeated evidence Intermittent fasting for adults with overweight or obesity.
2026 · The Cochrane database of systematic reviews · 1,995 participants
5 Repeated evidence Effects of Time-Restricted Feeding and Ramadan Fasting on Body Weight, Body Composition, Glucose Responses, and Insulin Resistance: A Systematic Review of Randomized Controlled Trials.
2022 · Nutrients
5 Repeated evidence Intermittent Fasting versus Continuous Calorie Restriction: Which Is Better for Weight Loss?
2022 · Nutrients
5 Repeated evidence Comparing caloric restriction regimens for effective weight management in adults: a systematic review and network meta-analysis.
2024 · The international journal of behavioral nutrition and p · 3,363 participants
5 Repeated evidence Is Caloric Restriction Associated with Better Healthy Aging Outcomes? A Systematic Review and Meta-Analysis of Randomized Controlled Trials.
2021 · Nutrients · 704 participants
5 Repeated evidence Beneficial effects of time-restricted fasting on cardiovascular disease risk factors: a meta-analysis.
2024 · BMC cardiovascular disorders
5 Repeated evidence Effect of exercise and/or reduced calorie dietary interventions on breast cancer-related endogenous sex hormones in healthy postmenopausal women.
2019 · Breast cancer research : BCR
5 Repeated evidence Fasting insulin, insulin resistance, and risk of cardiovascular or all-cause mortality in non-diabetic adults: a meta-analysis.
2018 · Bioscience reports
5 Repeated evidence Effects of dietary restriction on adipose mass and biomarkers of healthy aging in human.
2017 · Aging
5 Repeated evidence Effectiveness of intermittent fasting to potentiate weight loss or muscle gains in humans younger than 60 years old: a systematic review.
2021 · International journal of food sciences and nutrition
4 Large controlled trial Effect of a ketogenic diet, time-restricted eating, or alternate-day fasting on weight loss in adults with obesity: a randomized clinical trial.
2025 · BMC medicine · 160 participants
4 Large controlled trial Effects of 4:3 Intermittent Fasting on Eating Behaviors and Appetite Hormones: A Secondary Analysis of a 12-Month Behavioral Weight Loss Intervention.
2025 · Nutrients · 165 participants
4 Large controlled trial Fasting Versus a Heart-Healthy Diet Before Cardiac Catheterization: A Randomized Controlled Trial.
2024 · American journal of critical care : an official publica · 197 participants
4 Large controlled trial An Intermittent Fasting Intervention for Black Adults Can Be Feasibly Implemented in Black Churches: A Cluster Randomized Controlled Pilot Study.
2025 · Journal of the Academy of Nutrition and Dietetics · 2,022 participants
4 Large controlled trial An internet-based platform with a low-calorie dietary intervention improves cardiometabolic risk factors in overweight and obese people in China: Half-year follow-up results of a randomized controlled trial.
2024 · Diabetes, obesity & metabolism · 220 participants