Obesity, Diabetes, and The Dance of Insulin and Leptin
No substance in our body functions alone, and one of insulin’s closest working “partners” is another hormone called leptin.
Knowing about leptin has nothing to do with managing diabetes. However, understanding the insulin-leptin dynamic helps explain the association between obesity and the onset of type 2 diabetes.
Glucose, Insulin, and Leptin
The dance of insulin and leptin is influenced by blood sugar levels, and its sway on our body is twofold. First, leptin is largely responsible for the accuracy of insulin signaling, which means leptin plays a role in whether people become insulin resistant.
Second, the release of insulin to manage high blood sugar can lead to an overproduction of leptin. The process goes like this:
- Insulin is released to move surplus blood sugar into storage.
- Most of this surplus energy is stored as fat.
- Leptin is produced in fat cells, so having more fat cells means more leptin.
- Further, as sugar is metabolized in our fat cells, even more leptin is released.
The problem with having too much leptin in our body is the same as with having too much insulin—we become unresponsive to the hormone’s regulating effects.
Leptin and Our Appetite
One of leptin’s regulating effects has to do with appetite. Leptin assists with appetite control by signaling our brain when we’ve eaten enough. As we become increasingly leptin resistant, this “I’m full” signal is lost, leading to chronic hunger, overeating, an inability to adequately burn fat, and frequently obesity.
Many in the U.S. who are overweight, and those with prediabetes, likely have some degree of both insulin and leptin resistance. Unless lifestyle changes are made - wiser food choices and plenty of exercise - insulin and leptin resistance will persist, as does the prospect of developing type 2 diabetes.