Understanding eating topography: The key to reducing energy intake in humans?

点击翻译按钮获取中文摘要

According to the World Heath Organisation, obesity has more than doubled since 1980. Estimates suggest that obesity now affects around 1.5 billion people. This is worrying because the health and economic consequences are very clear. Obesity is a major risk factor for cardiovascular diseases, diabetes, and some cancers. One of the key observations about obesity is that not everyone becomes obese, even when they live in the same community, or even the same family. This means that some people appear to be 'protected.' Obesity researchers are interested in understanding why this is the case because this protection may hold the key to an effective treatment, or even a way to prevent obesity in the first place. For a long time, researchers and health professionals have suspected that obesity is associated with a particular eating style, eating quickly in particular. Indeed, it is sometimes said that we should chew our food several times in order to feel satisfied and to 'aid digestion.' Recently, researchers have begun to explore this idea systematically. The results are striking. For example, under controlled conditions, it would seem that eating at a slower rate produces both an increase in self-reported fullness and a reduction in meal size. Moreover, when we look at people across an entire country, we find that eating rate is a good predictor of bodyweight, even in large-scale studies. In 2010 researchers started to look at ways to reduce eating rate to see if this might be used to lower bodyweight. Their results were impressive. They used device called a mandometer to encourage children to eat at a slower rate. This training produced a clinically significant reduction in bodyweight, which was sustained 12 months post treatment. The prospect that we can manipulate eating behaviour to reduce energy intake is tantalizing because this approach has potential as an effective treatment for obesity. Moreover, an opportunity exists to change our eating behaviour by manipulating the physical characteristics of food. If this can be achieved then we may be able to design foods to encourage behaviours (e.g., slow eating) that reduce our calorie intake from meal to meal. Importantly, for these benefits to be realised, we need to discover the underlying mechanism. This is an important objective of this project. In the first instance we will develop a method to quantify and characterise 'eating topography' - collectively, the pattern of behaviours associated with eating; swallow rate, bite size, eating rate, and so on. With this tool, we will run a series of experiments to identify specific aspects of eating topography that influence our food intake. In a second set of experiments we will focus on the mechanism. Two hypotheses will be tested. Firstly, we will explore the prospect that a causal relationship exists between specific aspects of eating topography and the hunger and fullness that we experience at the end of a meal and during the period between meals. There are two reasons why this relationship might exist. Eating topography may change levels of hormones that control our appetite. Alternatively, it may influence the formation of memory for a meal - a process that is known to influence the amount of food that we eat at a subsequent meal. Our second hypothesis relates to the eating topography that is associated with particular foods. If a food is eaten with a topography that makes us feel full then we may remember this relationship. In future, when we encounter that food again, we may expect the food to be more filling and select a smaller portion. By this account, eating topography influences our energy intake by changing the way we make decisions about portion size, before a meal begins.