Cognitive and orosensory influences of food form on post-ingestive responses in humans

Bridget Ann Cassady, Purdue University

Abstract

Beverage consumption has been implicated in the overweight/obesity epidemic through the weaker energy compensation responses they elicit compared to solid food forms. However, plausible mechanisms have not been documented. While there is a strong genetic component to overweight/obesity, marked global increases over the past three decades implicates behavioral factors. The primary aim of the current study was to isolate and characterize the cognitive controls on human feeding and differential postingestive responses to isocaloric and macronutrient-matched beverage and solid food forms. This focus on cognitive factors stems from their importance in food choice and it is well documented that expectations of the post-ingestive consequences of a particular food influences feeding behavior and digestive and absorptive responses. The influences of adiposity and physical fitness were also explored to identify groups at potentially greater risk for positive energy balance associated with beverage consumption. Following screening assessments, 52 healthy adults were assigned to a lean/fit, lean/unfit, obese/fit or obese/unfit group and completed a four-arm, cross-over design study. Participants consumed isocaloric and macronutrient-matched beverage and solid preloads with messages that they would be liquid or solid in the stomach. However, they always posed a liquid gastric challenge. Appetite, gastric emptying, orocecal transit times, and selected endocrine responses were monitored for the following 4 hours. Total energy intake was also recorded. The oral beverage/gastric liquid load led to higher subsequent hunger and lower fullness ratings, greater challenge meal, post-visit, and total daily energy intake, more rapid gastric emptying, orocecal transit times, lower GLP-1 release, less suppression of ghrelin, and lower insulin concentrations during the postprandial period compared to oral solid and presumed solid gastric test loads. No significant patterns were observed between participant groups, suggesting that the cognitive controls on short-term regulation of feeding have equal influence on these groups. These data document the sensory and cognitive effects of food on ingestive behavior and identify physiological processes that may account for them. Consistent with other findings, they suggest that consumption of a clear, energy-yielding beverage may pose the greatest risk for positive energy balance. This study provides the initial step into mechanistic exploration of weaker appetitive and compensatory dietary responses following beverage compared to solid food forms. Integration of these experimental data with future long-term intervention evidence may aid in development of targeted therapeutic interventions.

Degree

Ph.D.

Advisors

Mattes, Purdue University.

Subject Area

Nutrition

COinS