Our appetite is controlled by a complicated interplay of hormones released by the brain and the gut which make us feel hungry or full (satiated). We now know there are many external influences which determine the release of hunger or satiety hormones such as energy needs, nutrient composition of our meals and timing between meals. For example protein and fat are more satiating than carbohydrate. Appetite regulation is a sophisticated process which food intake is closely correlated with energy expenditure. For example we consume approximately 1 million calories per year and in general that correlates with an energy expenditure of about 1 million calories.
Unfortunately the fine balance between hunger and satiety is challenged by modern life and the types of food we eat. Studies have shown that artificial sweeteners may negatively impact hunger peptides. Lack of sleep increases cortisol which effects hunger peptide release. Even our meal habits affect regulation. At one time we consumed our meals over longer intervals. This enabled the hormones that give us a feeling of fullness to be released sending a signal to the brain to stop eating. Today with high energy dense foods consumed on the run, the 1200 calorie lunch is already in our stomach before the feel full hormones are activated. A consequence of modern lifestyles is the overriding of built in mechanisms that keep energy consumption and expenditure in balance.
However all is not bleak. A recent study by British researchers looked at appetite regulation in people that exercise. The scientists found that higher levels of daily physical exercise improve our built in mechanism for appetite control. For example individuals with higher daily levels of physical activity had a reduced levels of hunger and an increase in satiety following a meal whereas the hunger and satiety mechanisms of their sedentary counterparts in the study were relative resistant to food intake levels.
The bottom line- higher levels of daily exercise will make the mechanisms that control your appetite more sensitive to the amount of food you consume and that's a good thing.
