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.
