Snacks containing whey protein and polydextrose induce a sustained reduction in daily energy intake over 2 wk under free-living conditions.

BACKGROUND: The manipulation of the composition of foods consumed as between-meal snacks may aid daily energy restriction.

OBJECTIVES: We compared the effects of the consumption of 2 energy-matched snack bars on appetite, energy intake (EI), and metabolic and endocrine responses. In addition, we investigated whether the acute effects of the consumption of snacks were maintained under free-living conditions and whether the habitual daily consumption of the snack over 14 d influenced these effects.

DESIGN: Ten lean men [mean ± SD age: 30.7 ± 9.7 y; body mass index (in kg/m(2)): 23.2 ± 2.8] consumed a whey protein and polydextrose (PPX) snack bar or an isoenergetic control snack bar as a midmorning, between-meal snack for 14 consecutive days in a double-blind, randomized, crossover design. The two 14-d intervention phases were separated by a 14-d washout period. On the first (day 1) and last (day 15) days of each intervention phase, appetite, food intake, and blood metabolite and endocrine responses were assessed under laboratory conditions. Free-living EI was recorded on days 4, 8, and 12 of interventions.

RESULTS: Total daily EI was significantly lower when the PPX snack was consumed during experimental days (10,149 ± 831 compared with 11,931 ± 896 kJ; P < 0.01), and daily EI remained lower when the PPX snack was consumed during the free-living part of the intervention (7904 ± 610 compared with 9041 ± 928 kJ; P < 0.05). The PPX snack was associated with lower glucose and ghrelin and higher glucagon-like peptide 1 and peptide tyrosine-tyrosine responses.

CONCLUSION: The manipulation of the composition of foods consumed as snacks is an effective way to limit subsequent EI. This trial was registered at clinicaltrials.gov as NCT01927926.