Carbohydrate “Addictions”

While not listed in the official diagnostic manual of the American Psychiatric Association (Diagnostic and Statistical Manual, 4th edition [DSM-IV]), addiction to carbohydrates has found its way into the vocabulary and psyche of the American consumer. This is partly fueled by popular diet plans that recommend limiting or avoiding carbohydrates as a way of promoting weight loss through reduced food intake. There are many mechanistic problems, however, with the concept and existence of an addiction to carbohydrates, although many people experience an intense desire for carbohydrate consumption similar to that for abused drugs.

The first problem with defining a desire for carbohydrate as an addiction comes from the fact that all living creatures require food, and many available foods found in nature contain carbohydrates. Therefore, you could say everyone is addicted to carbohydrates in some respect.

In order to ensure sufficient food intake for survival, the body has special systems that detect the levels of needed nutrients and signal the brain that it is time to eat and replenish the body's nutrient supply. These “time to eat” systems are countered by other systems that signal to the brain that it is “time to stop” eating. Aberrations in either the “eat” or “stop eating” systems can cause overconsumption of food with respect to the amount needed to maintain a healthy weight. This overconsumption of food can form the basis for the experience of “loss of control” over eating.

The second problem with defining a desire for carbohydrate as an addiction lies in the composition of carbohydrate foods people usually say they are addicted to, namely, ice cream, cookies, cakes, pies, chips, potatoes, pasta, and pizza.

While not an addiction in the strictest sense, many people experience intense cravings for carbohydrate-rich foods.

All of these foods contain fat and a small amount of protein as well as carbohydrate. Animal studies have shown that carbohydrate/fat containing foods, but not solely carbohydrate foods, cause an increase in the body's natural opioids, suggesting that the “addiction,” if it exists, may be to the fat, not the carbohydrate. If the carbohydrate in “high carbohydrate” foods is not [Page 110]the “addictive” agent, can it still contribute to the feeling of “loss of control” experienced when eating these foods? The answer is yes.

The sweetness of some carbohydrate foods helps promote release of dopamine, a neurotransmitter of the brain reward circuitry. This is perceived as a “time to eat” signal. Another source of “loss of control” with respect to carbohydrate in obese individuals lies in changes in the body's post-ingestive responses to carbohydrate.

Stop-Eating Signals

There is increased stomach capacity in the obese, which requires a greater amount of food to fill the stomach and activate one of the “stop eating” signals. Although many carbohydrate foods contain fat, consuming fat in an obese individual does not result in sufficient release of hormones that signal fullness (another “stop eating” signal). In addition, many obese individuals are resistant to insulin and leptin (other satiety hormones) signaling not only in the periphery but also in the brain. Peripheral insulin resistance creates a pseudo-hypoglycemic condition in which blood glucose (from carbohydrates) is high, but intracellular glucose is low.

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