Our appetites are regulated by a complex combination of hormones, hunger, and desire.1 Leptin and ghrelin, two hormones that have been recognized to have a major influence on energy balance, interact with a variety of other hunger and fullness signals to help keep our bodies fueled properly.1,2 Research has shown that those living with eating disorders may have difficulty regulating feelings of hunger and fullness.1
Leptin
Leptin, a hormone produced by fat cells that signals satiety, mediates the long-term regulation of energy balance by signalling to the individual that they are full.2 Lower leptin levels mean that it takes longer to feel full after eating.1 The following are regulators of circulating leptin levels:2
- Food intake: leptin levels increase
- Gender: leptin levels are higher in females than males
- Age: leptin levels decrease with increasing age
- Exercise: leptin levels decrease
- Glucose uptake: leptin levels increase
Research has found that leptin levels are noted to be higher in those living with binge eating disorder or anorexia nervosa, but lower in those living with bulimia nervosa.3 Exercise-induced amenorrhoea and anorexia nervosa are also associated with low leptin levels and show changes in neuroendocrine functioning.4
Studies have demonstrated that leptin may be involved in the neuroendocrine response to starvation, including changes in hormone concentrations, and possibly changes in sympathetic nervous system activity and reproductive function.2 As leptin plays a key role in energy homeostasis with low levels seen in malnourished states, if leptin levels are normalized, menstrual function and thyroid and bone markers may improve.4
Ghrelin
Ghrelin is a fast-acting hormone, seemingly playing a role in meal initiation.2 Ghrelin is secreted by the stomach and acts opposite to leptin, where high levels of ghrelin help trigger hunger by rising before a meal, and decreasing afterwards.1 The following are regulators of circulating ghrelin levels:2
- Food intake: ghrelin levels decrease
- Age: ghrelin levels decrease with increasing age
- Gender: ghrelin levels are higher in females than males
- Growth hormone: ghrelin levels decrease
- Glucose: ghrelin levels decrease
- Insulin: ghrelin levels decrease
Research has found that in those living with bulimia nervosa, ghrelin did not decrease as it normally would, indicating this may contribute to the likeliness of binge eating.3 In those living with anorexia nervosa, ghrelin levels are higher, however, ghrelin levels drop dramatically during the refeeding process.5
Recovery
The eating disorder recovery process can help to restore impaired ghrelin and leptin levels that are negatively impacted during the eating disorder. Ghrelin is increased in states of severe undernutrition, however, studies show that ghrelin can be normalized through weight restoration and eating disorder recovery.6
Similarly, leptin levels begin to restore during the recovery process although may not completely normalize until full weight restoration is achieved and maintained7. In bulimia nervosa, it is unclear whether impaired leptin levels normalize with recovery as there are mixed findings in the literature, thus additional research is required.7
At Change Creates Change Eating Disorder Care, we strive to educate other healthcare professionals about eating disorders. If you are interested in learning more, check out our Eating Disorder Care for Health Care Providers course.
