Scientific Study

BACKGROUND: Epidemiologic and clinical data indicate that nuts can be incorporated into the diet without compromising body weight. This has been attributed to strong satiety properties; increased resting energy expenditure; and limited lipid bioaccessibility. OBJECTIVE: The role of mastication was explored because of evidence that the availability of nut lipids is largely dependent on the mechanical fracture of their cell walls. DESIGN: In a randomized; 3-arm; crossover study; 13 healthy adults (body mass index; in kg/m(2): 23.1 +/- 0.4) chewed 55 g almonds 10; 25; or 40 times. Blood was collected and appetite was monitored during the following 3 h. Over the next 4 d; all foods were provided; including 55 g almonds; which were consumed under the same chewing conditions. Complete fecal samples were collected. RESULTS: Hunger was acutely suppressed below baseline (P < 0.05); and fullness was elevated above baseline longer (P < 0.05) after 40 chews than after 25 chews. Two hours after consumption; fullness levels were significantly lower and hunger levels were significantly higher after 25 chews than after 10 and 40 chews (P < 0.05). Initial postingestive glucagon-like peptide-1 concentrations were significantly lower after 25 chews than after 40 chews (P < 0.05); and insulin concentrations declined more rapidly after 25 and 40 chews than after 10 chews (both P < 0.05). Fecal fat excretion was significantly higher after 10 chews than after 25 and 40 chews (both P < 0.05). All participants had higher fecal energy losses after 10 and 25 chews than after 40 chews (P < 0.005). CONCLUSION: The results indicate important differences in appetitive and physiologic responses to masticating nuts and likely other foods and nutrients.