Effect of 24-h severe energy restriction on appetite regulation and ad libitum energy intake in lean men and women

Background: Intermittent severe energy restriction (SER) can induce substantial weight loss, but the appetite regulatory responses to SER are unknown and may dictate long-term dietary adherence.\ud \ud Objective: We determined the effect of 24-h SER on appetite regulation, metabolism, and energy intake.\ud \ud Design: Eighteen lean men and women completed two 3-d trials in randomized, counterbalanced order. On day 1 subjects consumed standardized diets containing 100% (mean 6 SD: 9.3 6 1.3 MJ; energy balance) or 25% [2.3 6 0.3 MJ; energy restriction (ER)] of energy requirements. On day 2, a standardized breakfast was consumed, with plasma concentrations of acylated ghrelin, glucagon-like peptide 1, insulin, glucose, and nonesterified fatty acids determined for 4 h. Ad libitum energy intake was assessed at lunch and dinner with subjective appetite and resting metabolism assessed throughout. On day 3, ad libitum energy intake was assessed at breakfast and by weighed food records.\ud \ud Results: Energy intake was 7% greater on day 2 (P