Carbohydrate Appetite, Fat Appetite and Obesity

描述(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。超重和肥胖的人越来越普遍，部分原因是环境因素，如丰富的可口的，高能量的食物，富含糖分和脂肪。高糖和高脂肪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味觉特性(风味)显然对动物有吸引力，并有助于饮食诱导的暴饮暴食。此外，这些营养素的口服后作用显著增强了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(满足)性质的，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，通过调节味道偏好和接受来影响食物的选择和消费。进餐时开始出现的饱腹感可能掩盖了口服后营养物质最初对摄取的刺激，这阻碍了对这些早期影响的研究。使用一种新方法，拟议中的研究将获得更具体的条件过程，该过程促进正在进行的一餐的摄取，并在随后的一餐中对该食物产生更大的吸引力。一直在食用味道温和的溶液和口腔后水的动物被转移到一种新的味道和口腔后营养相匹配的食物中，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量增加，表明营养已经被检测到，信号已经到达大脑。通过其他方法，包括使用缺失假定的感知和信号机制的元件的敲除小鼠模型，将研究这种关联过程的组成部分。这项应用的总体目标是确定口感和口腔后感觉刺激在获取碳水化合物和脂肪食欲中的联系过程。本项目的具体目标是：1)研究碳水化合物对摄入的刺激和味道偏好学习；2)调查脂肪摄入的刺激和味道偏好学习；3)评估脂肪味道和口后反馈对脂肪食欲和营养偏好的个体差异的作用。本研究涉及心理学、营养学、胃肠生理学等多个领域。了解味道是如何与食物的有益特性联系在一起的，加强偏好并导致暴饮暴食，对于找到限制食物摄取促进作用的方法至关重要。这一知识也可用于促进厌食症和恶病质的临床病例的进食。 与公共健康相关：该项目将研究碳水化合物和脂肪刺激饮食的过程，并导致人们对富含这些营养物质的食物的偏好。发现营养刺激饮食的控制将有助于开发治疗暴饮暴食、肥胖和厌食症的方法。

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.