One reason that people end up re-gaining their weight after dieting is the connection to hormonal influences.
The human body has appetite and weight regulating hormonal mechanisms that try to maintain homeostatis (keep things the same). Our bodies don’t generally want to change and if we try to alter things, our bodies will respond with compensation mechanisms, such as revving up our appetite hormones.
Three important hormones that shape our appetite are insulin, leptin and ghrelin.
Leptin may be one of the main hormones reponsible for rebound weight gain after a diet. Low levels of Leptin lead to increased hunger. Obese people (who produce large amounts of leptin) are resistant to its action. This is in a similar way that some people are resistant to insulin.
Your stomach makes Ghrelin when it is empty. If you want to lose weight you want less ghrelin, so you don’t get hungry.
Leptin and Ghrelin levels provide an explanation for the ups and downs of yo-yo dieting.
It has been shown that gastric bypass surgery can eliminate the effects of these hormones as the area of absorption is completely ‘bypassed’. However, the gastric bypass is high risk, invasive surgery that long termly alters the anatomy of the stomach.