Exploring the impact of intermittent fasting plus time-restricted eating versus calorie restriction on eating behavior, mood, sleep, quality of life in adults with obesity

BACKGROUND AND AIMS: Psychological and behavioural effects influence diet adherence and mediate the effectiveness of lifestyle interventions but are poorly studied with intermittent fasting approaches. Therefore, we compared the effects of intermittent fasting versus calorie restriction on eating behavior, mood, sleep, and quality of life after 6 months and 18 months. METHODS: ) with obesity were randomized to one of three groups (2:2:1): (i) intermittent fasting plus early time-restricted eating (iTRE, 30% energy requirements between 8am and 12pm followed by 20-h fasting three non-consecutive days, non-restricted on other days), (ii) calorie restriction (CR, 70% energy requirements), (iii) standard care (SC). Both iTRE and CR groups received nutritional support biweekly, whereas SC was provided healthy guidelines at baseline only. Eating behaviors, mood, sleep, mood and quality of life were assessed using validated questionnaires at month 0, 2, 6, 18. Mediation analysis was performed to examine the relationship between eating behavior and weight loss at 2 and 6 months. RESULTS: Greater weight loss was observed in iTRE and CR versus SC at month 2 and 6. However, greater increases in dietary restraint were observed in CR versus iTRE and SC at month 2, 6 and 18. Greater reductions in disinhibition and feelings of hunger were also observed in CR versus iTRE and SC at month 6. There was no detectable mediation effect of change in dietary restraint on weight loss, but disinhibition appeared to mediate the effect on weight loss in CR, accounting for 15% of the total treatment effect. CONCLUSION: Both intermittent fasting and CR effectively induce weight loss, but they potentially act through distinct behavioural pathways, with disinhibition playing a more prominent role in CR. CLINICALTRIALS: gov identifier, NCT03689608.