BACKGROUND AND PURPOSE:

• Intermittent fasting refers to eating windows separated by defined periods of fasting
  • Evidence related to risk and benefits remains limited
• Lowe et al. (JAMA Intern Med, 2020) sought to determine the effect of 16:8-hour time-restricted eating on weight loss for individuals who are overweight or obese

METHODS:

• 12 week randomized controlled trial
• Participants
  • Men and women aged 18 to 64 years
  • BMI: 27 to 43
• Interventions
  • Consistent meal timing group (CMT)
    • 3 structured meals per day
  • Time-restricted eating group (TRE)
    • Eat ad libitum from 12:00 pm until 8:00 pm
    • Completely abstain from caloric intake from 8:00 pm until 12:00 pm the following day
• Study design
  • Use of mobile application and a Bluetooth scale
    • A subset of participants underwent in-person testing
• Primary outcome
  • Weight loss
• Secondary outcomes (in-person cohort)
  • Changes in the following: Weight | Fat and lean mass | Fasting insulin and glucose | Hemoglobin A1c levels | Estimated energy intake | Total energy expenditure | Resting energy expenditure

RESULTS:

• 116 participants | In-person cohort: n = 25 TRE, n = 25 CMT
  • Mean age: 46.5 years | 60.3% men
• While those in the TRE group had a significant decrease in weight, there was no significant change between groups (P = 0.63)
  • Between groups: −0.26 kg (95% CI, −1.30 to 0.78)
• Agreement was strong between in-person weight measurements and at-home weight measurements
• Aside from appendicular lean mass which was significantly lower in the TRE group (low appendicular lean mass is associated with weakness and disability), there were no significant changes in any of the other secondary outcomes within or between groups
• There were no differences in estimated energy intake between groups or other metabolic markers

CONCLUSION:

• Time-restricted eating alone, without other interventions, is no more effective for weight loss vs eating throughout the day
• The authors conclude

Together, the results of this study do not support the efficacy of TRE for weight loss

Learn More – Primary Sources:

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

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What are the long-term consequences of early adult weight gain?

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