BACKGROUND AND PURPOSE:

• Time-restricted eating (TRE), also called intermittent fasting, without calorie counting has become a popular weight loss method
• Lin et al. (Ann Intern Med, 2023) studied whether TRE is more effective for weight control and cardiometabolic risk reduction vs calorie restriction (CR) or control

METHODS:

• Randomized controlled trial
• Participants
  • Between 18 and 65 years
  • BMI between 30 and 50 kg/m2
• Intervention
  • 8-hour TRE
    • Eating between noon and 8:00 p.m. only, without calorie counting
  • CR
    • 25% energy restriction daily
  • Control
    • Eating over a period of 10 or more hours per day
• Study design
  • 1:1:1 randomization
  • Participants were not blinded
  • Physical habits unchanged
  • This study took place over 12 months
    • TRE and CR interventions: 6-month weight loss phase and 6-month maintenance phase
• Primary outcome
  • Change in body weight at 12 months
  • Change in metabolic markers at 12 months
  • Change in energy intake at 12 months

RESULTS:

• 77 participants
  • Mean age: 40 (SD, 11) years
  • Black: 33% | Hispanic: 46%
• Mean reduction in energy intake
  • TRE: −425 (SD, 531) kcal/d
  • CR: −405 (SD, 712) kcal/d
• Compared with the control group, weight loss by month 12 was higher with both intervention groups
  • TRE group
    • Absolute weight loss: −4.61 kg (95% CI, −7.37 to −1.85) | P≤0.01
    • Weight loss as a percentage of baseline body weight: −4.87% (95% CI, −7.61 to −2.13)
  • CR group
    • Absolute weight loss: −5.42 kg (95% CI, −9.13 to −1.71) | P≤0.01
    • Weight loss as a percentage of baseline body weight: −5.30% (95% CI, −9.06 to −1.54)
• There was no significant difference in weight loss at 12 months between the TRE and CR groups
  • Absolute weight loss: 0.81 kg (95% CI, −3.07 to 4.69) | P=0.68
  • Weight loss as a percentage of baseline body weight: 0.43% (95% CI, −3.48 to 4.34)

CONCLUSION:

• Both CR and TRE improves weight loss compared to control
• There was no difference in weight loss between the CR and TRE groups
• The authors state

TRE is effective for weight loss when compared with controls eating over a period of 10 or more hours but not more effective than daily CR in a racially diverse population

Future studies are needed to confirm our findings

Learn More – Primary Sources:

Time-Restricted Eating Without Calorie Counting for Weight Loss in a Racially Diverse Population: A Randomized Controlled Trial