Carbohydrate Appetite, Fat Appetite and Obesity

描述（由申请人提供）：肥胖目前是一个主要的健康问题，增加了许多疾病的风险，包括糖尿病、心脏病、高血压和某些形式的癌症。超重和肥胖人群越来越普遍，部分原因是环境因素，比如大量美味、高能量、富含糖和脂肪的食物。高糖和高脂肪的食物也会促进实验动物的暴饮暴食和肥胖。高糖和高脂肪食物的感官特性（味道）显然对动物有吸引力，并导致饮食引起的暴饮暴食。此外，这些营养素的口服后作用显著增强了对碳水化合物和脂肪的食欲。口服后的营养作用最初被认为是完全抑制（饱腹）的性质，但最近的研究结果表明，营养物质具有积极（刺激）的进食后后果，通过调节风味偏好和接受来影响食物选择和消费。进餐时的饱腹感可以掩盖口服营养物质对摄入的最初刺激，这阻碍了对这些早期影响的研究。使用一种新方法，拟议的研究将获得更具体的条件作用过程，该过程促进了正在进行的用餐中的摄入，并在随后的用餐中赋予该食物更大的吸引力。一直饮用温和可口的溶液和口服后的水的动物被转移到一种新的味道和口服后的营养物质，并监测它们的摄食反应的变化。在肠道营养刺激的第一阶段摄入增加表明营养已经被检测到，并且信号已经到达大脑。通过其他方法，包括使用缺失假定传感和信号机制元素的敲除小鼠模型，将研究这种关联过程的组成部分。本应用程序的总体目标是确定口腔感觉和口腔后感觉刺激在碳水化合物和脂肪食欲的获得中相互关联的过程。该项目的具体目的是：1)研究碳水化合物对摄入和风味偏好学习的刺激；2)研究脂肪对摄入和风味偏好学习的刺激；3)评估脂肪味觉和口服后反馈对脂肪食欲的作用以及营养偏好的个体差异。这项研究涉及心理学、营养学和胃肠生理学等领域。了解味道如何与食物的奖励特性、强化偏好和导致暴饮暴食联系在一起，对于找到限制食物促进摄入作用的方法至关重要。这一知识也可应用于促进厌食症和恶病质临床病例的饮食。

DESCRIPTION (provided by applicant): Obesity is currently a major health problem that increases the risk of many diseases, including diabetes, heart disease, hypertension and some forms of cancer. The growing prevalence of overweight and obese individuals is attributed, in part, to environmental factors such as the abundance of palatable, energy dense foods that are rich in sugar and fat. High-sugar and high-fat foods also promote overeating and obesity in laboratory animals. The orosensory properties (flavor) of high-sugar and high-fat foods are clearly attractive to animals and contribute to diet-induced overeating. Furthermore, the post-oral actions of these nutrients significantly enhance carbohydrate and fat appetites. Post-oral nutrient actions were initially considered to be exclusively inhibitory (satiating) in nature, but recent findings demonstrate that nutrients have positive (stimulating) postingestive consequences that influence food choice and consumption by conditioning flavor preference and acceptance. The onset of satiation during meals can mask the initial stimulation of intake by post-oral nutrients, which has hindered the study of these early effects. Using a new method, the proposed studies will obtain more specific access to the conditioning process that promotes ingestion in an ongoing meal and confers greater attraction to that food in subsequent meals. Animals that have been consuming a mildly palatable flavored solution paired with post-oral water are shifted to a new flavor paired with post-oral nutrient, and the changes in their ingestive responses are monitored. Increased intake in the first session of intestinal nutrient stimulation indicates that the nutrient has been detected and a signal has reached the brain. With additional methods, including the use of knockout mouse models missing elements of putative sensing and signaling mechanisms, the components of this associative process will be investigated. The overall goal of this application is to determine the processes by which orosensory and post-oral sensory stimuli become linked in the acquisition of carbohydrate and fat appetite. The specific aims of this project are to 1) Investigate carbohydrate stimulation of intake and flavor preference learning; 2) Investigate fat stimulation of intake and flavor preference learning; and 3) Evaluate the role of fat taste and post-oral feedback on fat appetite and individual differences in nutrient preferences. This research involves the fields of psychology, nutrition, and gastrointestinal physiology. Understanding how flavors become linked to rewarding properties of foods, strengthening preferences and leading to overeating is crucial to finding ways to limit the intake-promoting effects of foods. This knowledge may also be applied to promote eating in clinical cases of anorexia and cachexia. PUBLIC HEALTH RELEVANCE: This project will examine the processes by which carbohydrates and fats stimulate eating and lead to preferences for foods high in these nutrients. Discovering the controls of nutrient-stimulated eating will assist the development of treatments for overeating and obesity as well as for anorexia.