Dependence comes from eating, not eating

2015/03/13 Galarraga Aiestaran, Ana - Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Dietetika/Elikagaiak
• Anatomia/Fisiologia
• Osasuna

Knowing and understanding factors and mechanisms related to obesity is not easy. The topic has many ends and one of them has to do with behavior. For example, eating disorders are widespread and there are people who have similar behavior to that of drug addicts with food. Thus, a few years ago researchers proposed that certain foods might be able to generate addiction. Since then there has been intense debate about this.

The debate intensified in 2009. In fact, the Rudd Center for Food Policy and Obesity at Yale University has first published a questionnaire to diagnose food dependence in that year. This is the Yale scale of food dependence (YFAS, Yale Food Addiction Scale), developed according to the criteria of the DSM-IV (Diagnostic and Statistical Manual of Mental Disorders).

This mental illness guide, developed by the American Psychiatric Association, is recognized in numerous international health systems. The latter is DSM-V which, among other things, classifies addictive substances and gives guidelines for their diagnosis and treatment.

Thus, the Rudd Center used the DSM-IV guidelines to develop the Yale scale following criteria similar to those used for the diagnosis of drug dependence. Its objective is to know if a person with inadequate behavior before food has food dependence or not. To do this, they analyze whether it fits the 25 expressions that the scale collects and to what extent. These statements include, for example, “Eating physically until you get sick,” and “Eating some less than normal foods, or stopping eating, I have had withdrawal symptoms, such as restlessness, anxiety, or other physical symptoms.”

Although the Yale scale was designed according to the DSM-IV guide and has received approval from several experts, the scientific community has not yet accepted it, nor the American Society of Psychiatry. For many, it is not clear that food has addictive capacity.

Food dependence in question

This issue has been analyzed by a group of European researchers with the support of the European Union. And its conclusion is that food dependence is not demonstrated; in any case, eating itself can cause in some cases dependence.

Researchers have released their research in the journal Neuroscience and Biobehavioral Reviews, through the article “Eating addiction”, rather than “food addiction”, better is addictive-like eating behavior.

While the article gives an account of the conclusion in the title itself, the text starts from the definition of dependence. Below is the classification of addictions and neurobiology, which distinguishes between eating by necessity or hedonism.

This distinction is not baladi. One of the authors of the article is Carlos Dieguez, a member of the University of Santiago de Compostela and the research team CIBERobn, according to which there is a notable difference between the two, and it is essential to consider this difference in obesity research.

Dieguez explained that we eat by necessity to take the calories and nutrients necessary for the functioning of the body. “This is very evident when we do intense exercise. In the end, we feel hungry and eat to recover what the body has spent.”

On the contrary, when eating by hedonism, food is taken without need. “In this case, we take the food because we like it, because it gives us pleasure and not because we are hungry. A typical example is family meals: before dessert arrives, we have our energy needs covered and, however, we do not give up the chocolate cake because we know that eating generates pleasure.”

Sugar, fat, salt

For some, including those taking into account the Yale scale, the explanation for this behavior would be, at least in some cases, food dependence. Dieguez and the team have warned that, although most mention certain foods (pizza, chocolate, chips...), each of them has many ingredients and has not been able to identify the cause of the addiction. Even if it is complete food, it has not been shown to have a similar effect to that of drugs and to generate an equivalent dependence.

The article analyzes the studies carried out with three substances considered addictive: sugar, fat and salt. In the case of sugar, experiments show that rats have symptoms similar to withdrawal syndrome in case of sugar rejection. In addition, if offered in exchange for an effort (tread a lever), they are willing to make more and more effort to get the dose of sugar. Moreover, most rats prefer to receive a dose of sugar than a dose of cocaine, except rats used to consuming cocaine.

However, researchers warn that they cannot distinguish whether the behavior of rats is due to sugar or their own custom, even through neuroimaging techniques. On the other hand, it is difficult to extrapolate to people what happens to rats. According to researchers, in people addictive behavior appears mixed with psychological and psychiatric elements such as memory, shame, guilt, routine, aggressiveness, depression and anxiety, and it is difficult to bring and test all that complexity to rats.

When analyzing studies with fat, researchers recalled that for most mammals (including ours) fat makes food more enjoyable. Thus, we prefer a food with a lot of fat than that without fat. In addition, they have highlighted that many of the hormones that regulate appetite (greline, leptin...) are related to fat. Therefore, they are not surprised to develop addiction-like behaviors in relation to high-fat foods.

In the mouse, for example, they have seen how they are able to accept an unpleasant environment in exchange for acquiring high-fat food. At the neurochemical level, some changes produced by fat are similar to those produced by sugar, but when fat is denied, there is no withdrawal syndrome similar to that caused by opiations. However, the problems or doubts that arise with sugar are the same as with fat to extrapolate to people research conducted in mice and rats.

Finally, the influence of salt has been analyzed. In fact, salt reinforces the taste of food and makes it more attractive. Also, although it does not have calories, the body needs it in part. But if mice are particularly attracted to salt from birth, it seems that in people the same is not the case. Apparently, our species has this attraction by birth with respect to sweet and, subsequently, does not develop any special attraction towards salt.

Researchers believe that interaction with other components accompanying salt may occur. In addition, they have not seen a neurological effect similar to that produced by sugar and fat in the case of fat. In turn, sugar and fat do not cause changes in the brain and behavior due to psychoactive substances. This is the conclusion of the researchers.

From conclusions to measures

Dieguez reiterates the article: “According to the studies carried out, it cannot be concluded that these substances [sugar, fat, salt] cause alterations in cocaine, alcohols, etc., both at the neurochemical and behavioral level or in the formation of withdrawal syndrome. In other words, the scientific evidence we currently have does not confirm the hypothesis that food ingredients cause the same effects as the factors causing drug dependence. In any case, the only exception can be caffeine.”

Yes, it recognizes that some people have similar behavior to addiction with respect to certain foods. “Because they eat too much and knowing that it will hurt them,” says Dieguez. “However, since there is no evidence that any food or ingredient, not even the interaction between ingredients, creates dependence, the classification of DSM-V addictions does not show food dependence.”

This affects the treatment of people with addiction-like behaviors: “If dependence was generated by a particular food, treatment would be directed to avoid its consumption. Alcoholics can take anything except alcohol, for we would look for something similar. If, on the contrary, dependence on food is the goal of treatment is to change behavior.”

The article shows more signs that addiction is not so much food as eating. For example, people with addiction-like behaviors usually do not limit their diet to a few foods or ingredients. On the contrary, the more variety you have, the more things you eat and, in the end, the more useless calories. This logically increases the tendency to be obese.

In this sense, researchers consider that the food industry has a direct influence on people who tend to adopt this behavior, making available foods rich in attractive and desirable calories. They therefore call on the authorities to take action and regulate the food industry. In addition, they consider it necessary to continue researching in this line, since they consider that the concept of dependence on food remains in “childhood”.