Edinburgh Napier University

  Nighttime eating is often associated with a negative impact on weight management and cardiometabolic health. However, data from recent acute metabolic studies have implicated a benefit of ingesting a bedtime snack for weight management. The present study compared the impact of ingesting a milk snack containing either 10 (BS10) or 30 g (BS30) of protein with a non-energetic placebo (BS0) 30 min before bedtime on next morning metabolism, appetite and energy intake in mildly overweight males (age: 24.3 (SEM 0.8) years; BMI: 27.4 (SEM 1.1) kg/m2). Next morning measurements of resting metabolic rate (RMR), appetite and energy intake were measured using indirect calorimetry, visual analogue scales and an ad libitum breakfast, respectively. Bedtime milk ingestion did not alter next morning RMR (BS0: 7822 (SEM 276) kJ/day, BS10: 7482 (SEM 262) kJ/day, BS30: 7851 (SEM 261) kJ/day, P = 0.19) or substrate utilisation as measured by respiratory exchange ratio (P = 0.64). Bedtime milk ingestion reduced hunger (P = 0.01) and increased fullness (P = 0.04) during the evening immediately after snack ingestion, but elicited no effect the next morning. Next morning breakfast (BS0: 2187 (SEM 365) kJ, BS10: 2070 (SEM 336) kJ, BS30: 2582 (SEM 384) kJ, P = 0.21) and 24 h post-trial (P = 0.95) energy intake was similar between conditions. To conclude, in mildly overweight adults, compared to a non-energetic placebo, a bedtime milk snack containing 10 or 30 g of protein does not confer changes in next morning whole-body metabolism and appetite that may favour weight management.