Dieting and Hunger
Numerous studies have demonstrated that as we decrease our caloric intake, our perceived hunger increases (2). The same is true following weight loss. The theory is that as we decrease our calorie intake and lose weight, our body stimulates appetite hormones to facilitate the regain of weight to maintain homeostasis (3). Some studies have even found that following weight loss, hunger can remain elevated for a year or even longer (3). This is one of the primary reasons why staying on track with a diet or maintaining your weight loss following a diet can be so tough.
Hormones and Hunger
Two important hormones responsible for regulating appetite are leptin and ghrelin. Leptin, which is produced mainly by adipose tissue, is released following increases in body fat percentage or increases in food intake. Once released into the bloodstream it possesses the ability to cross the blood brain barrier and communicate the body’s energy status to the hypothalamus. When leptin reaches the hypothalamus it essentially says that we have enough body fat, which in the healthy individual leads to a decrease in food intake and an increase in energy expenditure (4). To simplify all of this, in a properly functioning individual, as we are on the verge of increasing our body fat stores, our fat cells will release leptin to tell our body to decrease food intake and increase activity. It has been demonstrated also that an increase in leptin can lead to weight loss (5)!