The Mouth - Gut - Brain Model

肥胖及相关疾病，如2型糖尿病和心血管疾病，是全球主要的健康问题。一个促成因素是过度消耗能量密集的食物，富含脂肪和糖，我们的享乐和生理欲望驱使我们消耗能量丰富的食物。一种方法是在保持感官质量的同时减少食物的能量含量。食品工业已经开发出一系列更健康的产品。为了使这些产品获得成功，消费者必须继续购买和消费它们。然而，最近的研究表明，减少食物的能量含量可能会产生意想不到的后果。具体来说，如果一种食物看起来和尝起来都富含营养，肠道和大脑系统就会摄入大量的能量。如果这种情况没有发生，就像在低热量食物的情况下，大脑似乎会诱导饥饿信号，驱使个体在随后的几餐中过度消费（反弹饥饿），导致卡路里摄入量增加，从而抵消消耗低热量食物的整体效果。这导致消费者对这些产品的不满，并可能导致食欲和饥饿激素的失衡，而这些失衡往往会导致节食后体重迅速增加。因此，我们需要重新思考如何更有效地利用低热量食物来控制能量摄入。要做到这一点，我们需要了解我们如何感知食物，我们如何消化和吸收营养，以及大脑如何对这些过程做出反应并控制随后的食欲信号之间的关系。这个口-肠-脑系统是控制食欲和能量摄入的关键。这个项目的目的是了解食物的感官特性和营养摄入之间的不匹配是如何控制我们的食欲和饥饿反弹的。我们要解决的关键问题是，在反弹饥饿和过度消费发生之前，一种食物的能量含量可以降低多少？关键的影响将是我们修改配方食品的能力，以减少感官和营养信号之间的差距，以减少能量替代品的满足，而不会导致随后的过度消费。该项目将重点关注脂肪，因为脂肪的能量含量最高，而低脂肪食品的感官特性对消费者和食品行业都是具有挑战性的。我们将通过确定感官特性如何控制消费者对饱腹感的期望（“饱腹感”）来调查减少食物脂肪含量的影响，并测量在消费者在随后的一餐中产生反弹饥饿感和过度消费之前我们可以减少多少脂肪含量。利用这些信息，我们将设计一种更真实的食物，其结构，物理行为和感官特性密切匹配，但有一系列的脂肪含量和脂肪类型，以仔细控制多少脂肪被“感知”和多少被吸收。我们将测量这些食物的食欲反应如何控制下一餐食物的消耗；研究对食物中脂肪含量敏感或不敏感的个体之间的差异。这将决定我们能在多大程度上改变食物的感官和脂肪含量，并在随后的几餐中保持整体的能量减少。研究结果将提供有价值的信息，说明口腔-肠道-大脑信号是如何从根本上控制食欲的，并开始揭示为什么不同的人在食用低热量食物后更容易产生饥饿感。这项研究还将使我们能够确定一个更广泛的研究计划，以调查口腔-肠道-大脑界面，从而更详细地研究个体反应之间的差异，以及我们行为测量（如肠道激素水平）背后的生物机制。由此产生的知识将有助于找到更好的方法来生产低热量食品，从而更有效地减少长期的能量摄入。

Obesity and associated conditions such as type 2 diabetes and cardiovascular disease are major global health concerns. A contributing factor is overconsumption of energy dense foods, rich in fat and sugar, driven by our hedonic and physiological desire to consume energy rich foods. One approach has been to reduce the energy content of foods whilst retaining the sensorial quality. The food industry has developed a wide range of healthier products. In order for these products to be successful, consumers must continue to purchase and consume them. However, recent studies have suggested that reducing the energy content of a food may have unintended consequences. Specifically, if a food looks, and tastes like it is rich in nutrients, the gut and brain systems prepare to expect a high energy intake. If this does not happen, as in the case of a reduced calorie food, the brain appears to induce hunger signals that drive the individual to overconsume at subsequent meals (rebound hunger), resulting in an increased calorie intake, thus negating the whole effect of consuming the reduced calorie food. This leads to consumer dissatisfaction with these products, and potentially to imbalances in appetite and hunger hormones that often cause rapid weight gain following periods of dieting.Therefore we need to rethink how reduced calorie foods can be used more effectively to control energy intake. To do this, we need to understand the relationship between how we sense foods, how we digest and absorb the nutrients and how the brain responds to these processes and controls subsequent appetite signalling. This Mouth-Gut-Brain system is key to controlling our appetite and energy intake. The aim of this project is to understand how the mismatch between sensory properties and nutrient intake of food controls our appetite and rebound hunger. The key question we aim to address is, by how much can the energy content of a food be reduced before rebound hunger and overconsumption occurs? The key impact will be our ability to modify reformulated foods to reduce the gap between sensory and nutrient signals in order for reduced-energy alternatives to satisfying and not result in subsequent over-consumption.This project will focus on fat, as fat has the highest energy content, and the sensory properties of low fat foods are challenging for both consumers and the food industry. We will investigate the impact of reducing the fat content of foods by determining how the sensory properties control consumer expectations of satiety (feeling of "fullness"), and measure how much we can reduce fat content before consumers develop rebound hunger and overconsume at a subsequent meal.Using this information we will design a more realistic food where the structure, physical behaviour and sensory properties are closely matched, but with a range of fat contents and fat type, to carefully control how much fat is "sensed" and how much is absorbed. We will measure how the appetite response of these foods controls the consumption of food in a following meal; and study differences between individuals who are sensitive or insensitive to fat content in foods. This will determine how much we can alter the sensory and fat content of food and still maintain an overall reduction in energy across subsequent meals. Results will provide valuable information on how mouth-gut-brain signalling fundamentally controls appetite, and begin to unravel why different individuals may be more susceptible to rebound hunger following the consumption of reduced calorie foods. The research will also enable us to define a broader research programme to investigate mouth-gut-brain interface that will study in more detail variations between individual responses, and the biological mechanisms behind our behavioural measures (such as gut hormone levels).Knowledge generated will enable better approaches to reduced calorie foods that are more effective at reducing energy intake in the longer term.