Effect of Food Temperature and Diet Composition on Satiety, Satiety Hormones, Chewing Time and Neuronal Activity

Overview

Obesity and its related illnesses have become serious health issues, obesity is today the fifth most common cause of death. Obesity rate has dramatically enhanced in both male and female, and across all ages. Food and energy intake during habitual meals, energy balance, energy expended during physical activity, all play an important role in management of weight. Lifestyle changes and nutritional strategies are emerging as the best line of treatment for obesity. The achievement of satiety along with, the reduction in dietary intake is the primary goal of nutritionists and food scientists. Appetite control can be defined by two terms; satiety and satiation. The interaction between appetite, food intake, and hormones secreted by the gastrointestinal tract, which are secreted in response to macronutrients like carbohydrates, fats and proteins are the satiety regulators. The gut hormones including glucagon like peptide 1(GLP1), cholecystokinin (CCK) are anorexigenic in action, cause slowing of meal digestion and reduce food intake thus inducing satiation and satiety. The CCK hormone plays a key role in delaying of stomach emptying by fundus relaxation and antral inhibition, ultimately causing major satiation. The incretin hormone GLP-1's main action is to stimulate insulin secretion, inhibit glucagon secretion, regulating postprandial glucose and provide negative feedback to the stomach thereby controlling appetite. Research is needed in meal properties and different diets which may affect gut-brain signaling and altering the mechanisms of gut hormonal secretion, thus further influencing appetite satiation and satiety scores. This knowledge can be utilized in energy expenditure and weight management. Serving temperatures alter perceived intensities, flavor and acceptances of food as well. Brain areas work in close association with the thermal perception and emotions. In neuroimaging studies neural changes have been when body is exposed to different temperatures either environmental or oral cavity. Temperature of food play an important role in the palatability and affective value of food and, consequently, in appetite regulation. Limited research has been done so far how food temperature is related to sensory perception and satiety Chewing and food texture also affect satiety and satiation. The oral processing, eating rate and physical forms of food i.e., solid versus liquid or semi-solid are all physiologically related to satiety and an individual's behavior to understand this oral sensory satiety effect, requires further studies. The number of chews has been studied showing an association between reduction in food intake with increasing number of chews. EEG is a noninvasive neuroimaging technique, helping in evaluating the cognitive part of food stimuli and food ingestion in relation to gut hormones. Sensory properties of previously identified as drivers of refreshing perception, enhance alpha and beta brain oscillations as observed in prior EEG studies. Many factors influence satiety including food composition, temperature, environment, last meal and preload. Limited literature is available about temperature of food and its influence on satiety. My study aims to find 1) the effect of temperature of high carbohydrate, high fat meal and high protein meal on the satiety scores, satiety-related hormones, EEG and EMG. 2. To find the effect of chewing time of food on the satiety scores, satiety- related hormones, EEG and EMG.