A claim you hear on longevity podcasts
The claim checked: The weight and insulin benefits of time-restricted eating appear to come from eating fewer calories Hear it at 45:15
Four of ten studies found a short eating window added no benefit beyond eating less. Two early-eating studies saw metabolic gains beyond weight loss, and four were mixed, one finding slightly more weight loss.
Computed from 10 studies that test this point, each judged by two readers, in full. 10 more studies are waiting for a full read and do not count yet.
“is there any difference between them and i think the answer today is no i think the answer is nope when people talk about how time-restricted feeding is helping them lose weight and manage insulin resistance and things like that i think it appears that that's all due to reduced caloric intake”
controlled trial · 2020 · landmark
“Time-restricted eating, in the absence of other interventions, is not more effective in weight loss than eating throughout the day.”
Effects of Time-Restricted Eating on Weight Loss and Other Metabolic Parameters in Women and Men With Overweight and Obesity: The TREAT Randomized Clinical Trial. JAMA Intern Med
Who: US adults aged 18-64 with BMI 27-43, without diabetes (mean age 46.5, 60% men)
PMID 32986097
controlled trial · 2022 · landmark
“These results indicate that caloric intake restriction explained most of the beneficial effects seen with the time-restricted–eating regimen.”
Calorie Restriction with or without Time-Restricted Eating in Weight Loss. N Engl J Med
Who: Adults with obesity (BMI 28-45) aged 18-75 in Guangzhou, China, without diabetes (mean age 31.9)
PMID 35443107
controlled trial · 2025 · landmark
“In a 12‐week intervention, TRE did not lead to significant improvements in weight, average body composition, or glycemic or metabolic measures compared with CR or UE.”
Time-restricted eating, caloric reduction, and unrestricted eating effects on weight and metabolism: a randomized trial. Obesity (Silver Spring)
Who: 88 adults aged 18-65 with obesity (BMI 30-55) and without diabetes, mean age 43.2, BMI 36.2, Minnesota
PMID 39973006
systematic review · 2025 · landmark
“We showed that ADF improved several cardiometabolic risk factors, including non-high density lipoprotein cholesterol, triglycerides, and total cholesterol, while TRE and WDF generally did not result in additional benefits to CER.”
Intermittent fasting strategies and their effects on body weight and other cardiometabolic risk factors: systematic review and network meta-analysis of randomised clinical trials. BMJ
Who: adults, median age 45, mostly overweight/obesity, in RCTs of intermittent fasting, continuous energy restriction or ad-libitum diets
PMID 40533200
other primary study · 2022 · landmark
“Though we could not trace this energy deficit to changes in physical activity or food intake, we suspect that eTRE did reduce energy intake, but we were unable to detect it owing to the well-known limitations of accurately assessing food intake via self-report.”
Effectiveness of Early Time-Restricted Eating for Weight Loss, Fat Loss, and Cardiometabolic Health in Adults With Obesity: A Randomized Clinical Trial. JAMA Intern Med
Who: adults aged 25-75 with obesity (BMI 30-60, no diabetes) at the UAB Weight Loss Medicine Clinic; 80% female, mean age 43
PMID 35939311
pooled analysis · 2025
“In conclusion, IF combined with CR is an effective approach for achieving health benefits such as weight loss but does not provide additional health benefits beyond those achieved by CR.”
Is isocaloric intermittent fasting superior to calorie restriction? A systematic review and meta-analysis of RCTs. Nutr Metab Cardiovasc Dis
Who: Adults aged 18-75, mostly overweight/obese, some with T2D, prediabetes, NAFLD, metabolic syndrome or gestational diabetes; isocaloric IF+CR vs CR (5:2, ADF and TRE)
PMID 39732588
pooled analysis · 2024
“The TRE diet showed a greater weight loss than CER diet (WMD: –0.93 kg; 95% CI: –1.69 to –0.17; k = 6; P = 0.016), whereas ADF and the 5:2 diet achieved a comparable weight loss as the CER diet.”
Effects of Intermittent Energy Restriction Compared with Those of Continuous Energy Restriction on Body Composition and Cardiometabolic Risk Markers - A Systematic Review and Meta-Analysis of Randomized Controlled Trials in Adults. Adv Nutr
Who: Apparently healthy adults (normal weight, overweight or obese; mean age 27-68, mean BMI 22-40) in parallel RCTs comparing TRE, ADF or 5:2 with continuous energy restriction; people with diabetes, NAFLD or cancer excluded
PMID 37827491
pooled analysis · 2023
“However, compared with CR alone, TRE plus CR exhibited no significant benefit on the blood pressure, glucose profile, and lipid profile.”
Time-restricted eating with calorie restriction on weight loss and cardiometabolic risk: a systematic review and meta-analysis. Eur J Clin Nutr
Who: Adults over 18 with overweight or obesity (one trial in type 2 diabetes), mostly women (147 of 579 male), in China, Brazil, US and Czech Republic
PMID 37488260
trial or observed group · 2018 · landmark
“In conclusion, five weeks of eTRF improved insulin levels, insulin sensitivity, β cell responsiveness, blood pressure, and oxidative stress levels in men with prediabetes—even though food intake was matched to the control arm and no weight loss occurred.”
Early Time-Restricted Feeding Improves Insulin Sensitivity, Blood Pressure, and Oxidative Stress Even without Weight Loss in Men with Prediabetes. Cell Metab
Who: 8 overweight men with prediabetes (aged 56 ± 9 years, mean BMI 32.2) completing a supervised crossover feeding trial
PMID 29754952
other primary study · 2020
“The metabolic benefits of eTRF are independent of its effects on weight loss and represent chronic adaptations rather than the effect of the last bout of overnight fast.”
Two weeks of early time-restricted feeding (eTRF) improves skeletal muscle insulin and anabolic sensitivity in healthy men. Am J Clin Nutr
Who: 16 healthy young men (aged 23, BMI 24) in two non-randomised groups
PMID 32729615
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