Time-restricted eating

Practical note

Graded moderate: many randomised trials pooled in a 2025 network meta-analysis (99 trials, 6582 adults across fasting strategies) and a 2026 meta-analysis (30 studies, 1341 adults; about 2.8 kg more weight loss than non-calorie-matched controls); downgraded one level because most trials are short and participants cannot be blinded to the diet.

Sources

• Supports“TRE yields favorable anthropometric and clinical outcomes, even when intake is isocaloric between the intervention and control groups.” (Abstract, conclusion) Fernandes-Alves D, Teixeira GP, Guimaraes KC, Crispim CA. 2026. Nutrition Reviews. Systematic Review and Meta-analysis of Randomized Clinical Trials Comparing Time-Restricted Eating With and Without Caloric Restriction for Weight Loss. publisher copyright; metadata and short quotes only; Courtesy of the U.S. National Library of Medicine
• Supports“All intermittent fasting and continuous energy restriction diet strategies reduced body weight when compared with ad-libitum diet.” (Abstract, results) Semnani-Azad Z, Khan TA, Chiavaroli L, Chen V, Bhatt HA, Chen A, Chiang N, Oguntala J, Kabisch S, Lau DC, Wharton S, Sharma AM, Harris L, Leiter LA, Hill JO, Hu FB, Lean ME, Kahleova H, Rahelic D, Salas-Salvado J, Kendall CW, Sievenpiper JL. 2025. BMJ. Intermittent fasting strategies and their effects on body weight and other cardiometabolic risk factors: systematic review and network meta-analysis of randomised clinical trials. publisher copyright; metadata and short quotes only

Practical note

Graded moderate: a 12-month randomised trial of 139 adults (eating window 8 am to 4 pm, net difference -1.8 kg, not significant), a 2024 systematic review of 7 energy-matched trials in which most found no added benefit, and a 2025 network meta-analysis finding similar benefits to continuous energy restriction; downgraded one level for inconsistency, since a 2026 meta-analysis found about 1.5 kg more weight loss with time-restricted eating against calorie-matched controls.

Sources

• Supports“The addition of TRE to CR regimens resulted in greater weight loss and improvements in cardiometabolic risk factors in some studies; however, the majority of studies did not find additional benefits.” (Abstract, conclusions) Ezzati A, McLaren C, Bohlman C, Tamargo JA, Lin Y, Anton SD. 2024. Obesity (Silver Spring). Does time-restricted eating add benefits to calorie restriction? A systematic review. publisher copyright; metadata and short quotes only; Courtesy of the U.S. National Library of Medicine
• Supports“Among patients with obesity, a regimen of time-restricted eating was not more beneficial with regard to reduction in body weight, body fat, or metabolic risk factors than daily calorie restriction.” (Abstract, conclusions) Liu D, Huang Y, Huang C, Yang S, Wei X, Zhang P, Guo D, Lin J, Xu B, Li C, He H, He J, Liu S, Shi L, Xue Y, Zhang H. 2022. New England Journal of Medicine. Calorie Restriction with or without Time-Restricted Eating in Weight Loss. publisher copyright; metadata and short quotes only; Courtesy of the U.S. National Library of Medicine
• Supports“The current evidence provides some indication that intermittent fasting diets have similar benefits to continuous energy restriction for weight loss and cardiometabolic risk factors.” (Abstract, conclusions) Semnani-Azad Z, Khan TA, Chiavaroli L, Chen V, Bhatt HA, Chen A, Chiang N, Oguntala J, Kabisch S, Lau DC, Wharton S, Sharma AM, Harris L, Leiter LA, Hill JO, Hu FB, Lean ME, Kahleova H, Rahelic D, Salas-Salvado J, Kendall CW, Sievenpiper JL. 2025. BMJ. Intermittent fasting strategies and their effects on body weight and other cardiometabolic risk factors: systematic review and network meta-analysis of randomised clinical trials. publisher copyright; metadata and short quotes only
• Opposes“This result suggests that circadian effects may enhance the impact of CR on excess weight.” (Abstract, conclusion) Fernandes-Alves D, Teixeira GP, Guimaraes KC, Crispim CA. 2026. Nutrition Reviews. Systematic Review and Meta-analysis of Randomized Clinical Trials Comparing Time-Restricted Eating With and Without Caloric Restriction for Weight Loss. publisher copyright; metadata and short quotes only; Courtesy of the U.S. National Library of Medicine

Practical note

Graded moderate by the meta-analysis authors with GRADE: 10 randomised trials, 599 participants, mean duration 4 months, eating windows of 4 to 10 hours a day; pooled fasting glucose fell by 0.30 mmol/l and body weight by 1.6 kg. Imprecision from small trials limited the evidence.

Sources

• Supports“Moderate-certainty evidence indicates that TRE reduces fasting blood glucose but not HbA1c.” (Abstract, conclusions and interpretation) Viple F, Pedersen SS, Andersen TH, Raben A, Termannsen AD, Salling J. 2026. Diabetologia. Effects of time-restricted eating on markers of glucose metabolism and regulation in individuals with prediabetes or type 2 diabetes: a systematic review and meta-analysis of randomised controlled trials. publisher copyright; metadata and short quotes only; Courtesy of the U.S. National Library of Medicine

Practical note

Graded low: the primary meta-analysis pooled only 4 randomised trials with 323 participants (no heterogeneity), and hunger is a self-reported outcome in unblinded trials; downgraded for imprecision and risk of bias.

Sources

• Supports“In conclusion, the TRE protocol was associated with elevated hunger compared to isocaloric strategies” (Abstract) Silva AD, Guimaraes KC, Oliveira RA, Rosa DA, Crispim CA. 2025. Nutrition Research. Time-restricted eating increases hunger in adults with overweight and obesity: A systematic review and meta-analysis of randomized controlled studies. publisher copyright; metadata and short quotes only; Courtesy of the U.S. National Library of Medicine

Practical note

Graded low: 15 randomised trials with 1365 adults pooling several intermittent fasting regimens (indirect for time-restricted eating specifically), study quality assessed only with the Jadad scale, and few long trials. The 12-month NEJM trial also found no substantial difference in adverse events.

Sources

• Supports“In addition, there were no substantial differences between the groups in the numbers of adverse events.” (Abstract, results) Liu D, Huang Y, Huang C, Yang S, Wei X, Zhang P, Guo D, Lin J, Xu B, Li C, He H, He J, Liu S, Shi L, Xue Y, Zhang H. 2022. New England Journal of Medicine. Calorie Restriction with or without Time-Restricted Eating in Weight Loss. publisher copyright; metadata and short quotes only; Courtesy of the U.S. National Library of Medicine
• Supports“This meta-analysis suggested that IF was not associated with a greater risk of AEs in adult patients affected by overweight or obesity.” (Abstract, conclusions) Zhong F, Zhu T, Jin X, Chen X, Wu R, Shao L, Wang S. 2024. Nutrition Journal. Adverse events profile associated with intermittent fasting in adults with overweight or obesity: a systematic review and meta-analysis of randomized controlled trials. publisher copyright; metadata and short quotes only; Courtesy of the U.S. National Library of Medicine