Skim milk compared with a fruit drink acutely reduces appetite and energy intake in overweight men and women

Background: Several studies show that proteins, including whey and casein, are more satiating than carbohydrates. It follows that skim milk would be more satiating than sugar-rich beverages. However, this has yet to be shown. Objective: The objective was to investigate the effects of drinking skim milk in comparison with a fruit drink at breakfast on self-reported postmeal satiety and energy intake at lunch. Design: In a randomized crossover trial, 34 overweight women (n = 21) and men (n = 13) attended 2 sessions 1 wk apart. At each session, participants consumed a fixed-energy breakfast together with either 600 mL skim milk (25 g protein, 36 g lactose, < 1 g fat; 1062 kJ) or 600 mL fruit drink (< 1 g protein, 63 g sugar, < 1 g fat; approximate to 1062 kJ). Participants provided satiety ratings throughout the morning. Four hours after breakfast they consumed an ad libitum lunch, and energy intake was assessed. Results: Participants consumed significantly less energy at lunch after consuming skim milk (mean: 2432 kJ; 95% CI: 2160, 2704 kJ) than after consuming the fruit drink (mean: 2658 kJ; 95% CI: 2386, 2930 kJ), with a mean difference of approximate to 8.5% (P < 0.05). In addition, self-reports of satiety were higher throughout the morning after consumption of skim milk than after consumption of the fruit drink (P < 0.05) with the differences becoming larger over the 4 h (P < 0.05). Conclusion: Consumption of skim milk, in comparison with a fruit drink, leads to increased perceptions of satiety and to decreased energy intake at a subsequent meal. This trial was registered with the Australian New Zealand Clinical Trials Registry at www.anzctr.org.au as ACTRN12608000510347. Am J Clin Nutr 2009;90:70-5.