Insulin resistance in type 2 diabetes may promote obesity

Many physicians tell their patients who have type 2 diabetes to be careful of what they eat. This is because some studies have shown that weight loss may help reduce the symptoms of or even reverse type 2 diabetes.

However, a recent study published in the journal Cell Metabolism indicated that individuals who have type 2 diabetes should not only monitor the nutritional content of their food, but also whether or not they are eating because they are hungry.

The researchers explained that in non-diabetics, insulin increases the amount of dopamine that is released through neurons in the brain. This chemical has been associated with feelings of reward and motivation.

However, insulin resistance slows down the rate at which dopamine is released. Therefore, the investigators hypothesized that people who do not respond normally to the hormone would consume more food as a way to satisfy their desire for the rewarding effect of eating.

The study's results showed that when mice were genetically altered to develop insulin resistance, they consumed more food and subsequently became obese.

"Once you become obese or slide into a positive energy balance, insulin resistance in [the brain's reward center] may drive a vicious cycle. There is no evidence this is the beginning of the road to obesity, but it may be an important contributor to obesity and to the difficulty we have in dealing with it," said lead researcher Jens Bruning.

These findings may be especially noteworthy for individuals with type 2 diabetes who want to control their weight.

To help people avoid overeating, the American Diabetes Association recommends that individuals with type 2 diabetes evaluate their portion sizes. For example, a single serving of cheese should be no larger than one ounce, or about the size of a person's thumb. Three ounces is the standard serving size for meat, poultry and fish, which can be compared to the size of an individual's palm.