Why We Crave Sugar When We're Stressed

It can happen fast. One minute, you’re indulging in a small piece of chocolate; the next, you’re surrounded by empty candy wrappers — and still craving more. In America, uncontrolled sugar consumption is a concern because of its contributions to obesity and diabetes. A recent study investigated the psychological basis of sugar cravings during times of stress. Researchers proposed that sugar turns down the stress response in the human brain. As a result, we may be consuming sugar as a quick way to hold back feelings of stress.

Although our brain accounts for just 2 percent of our body weight, the organ consumes half of our daily carbohydrate requirements—and glucose is its most important fuel. Under acute stress the brain requires some 12 percent more energy, leading many to reach for sugary snacks.

Carbohydrates provide the body with the quickest source of energy. In fact, in cognitive tests subjects who were stressed performed poorly prior to eating. Their performance, however, went back to normal after consuming food.

When we are hungry, a whole network of brain regions activates. At the center are the ventromedial hypothalamus (VMH) and the lateral hypothalamus. These two regions in the upper brain stem are involved in regulating metabolism, feeding behavior and digestive functions. There is, however, an upstream gatekeeper, the nucleus arcuatus (ARH) in the hypothalamus. If it registers that the brain itself lacks glucose, this gatekeeper blocks information from the rest of the body. That’s why we resort to carbohydrates as soon as the brain indicates a need for energy, even if the rest of the body is well supplied.

Sugar's unique role in addiction and obesity have led some doctors to argue that it should be regulated as a controlled substance. Among the most vocal proponents is University of California-Los Angeles' Robert Lustig. "Food should confer wellness, not illness. The industry feeds our sugar habit to the detriment of our society. We need food purveyors, not food pushers," Lustig wrote in the Atlantic last year, arguing that sugar meets all the legal standards of a drug. Neurological addiction, he claimed, is a non-essential nutrient, and causes significant social harms.

For some, the brain cannot get its energy from the body’s reserves, even if there are enough fat deposits. The most important cause of this is chronic stress. To ensure their brains are not undersupplied, these people must always eat enough. Often the only way out of such eating habits is to leave a permanently stressful environment. So although many tend to be hard on themselves for eating too many sweets or carbs, the reasons behind such craving aren’t always due to a lack of self-control and might require a deeper look into lifestyle and stressful situations—past and present. Once the root cause of stress addressed, eating habits could ultimately resolve themselves.


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