The ability of food to act in a drug-like manner has been observed in the nutritional literature. This suggests that foods can be addictive and may lead to drug-like addiction. Generally high quality foods as found in traditional diets do not have this effect. Diets containing high concentrations of essential nutrients, whole foods and unrefined and unprocessed produce tend to allow normal appetite regulation and facilitate the maintenance of stable body weight. However, the Western Diet is implicated in obesity and this may relate to the addictive properties of the foods it contains, which encourages overeating, and limit the ability of the hypothalamus to correctly regulate appetite and energy utilisation. Consumption of the Western diet therefore may be the route cause of weight gain and obesity. Refined flour, sugars, caffeine, salt and fats comprise a large part of the Western diet and high intakes of these foods offer an explanation as to why addiction is possible from regular consumption of such a diet.
The association between the consumption of fast foods and obesity is well established in the nutritional literature. In particular, soft drinks are thought to be a primary driver of obesity due to their high fructose and low fibre content. The increased consumption of sugars such as fructose and high fructose corn syrup, as well as refined flour has been shown to correlate strongly with the increased rise in the prevalence of obesity in developed nations. Fructose is particularly detrimental because it has been shown to rapidly cause insulin resistance in mammals even at reasonable intakes. This correlation does not prove cause and effect and also does not prove the case for addiction. However, a number of well designed animal and humans studies have shown that foods do possess the potential for addiction. The results of some studies that have shown the addictive potential for foods have lead some researchers to liken food addiction to that of drug addiction, particularly the pleasure seeking behaviour foods can induce.
The drug-like properties of foods are controversial, but evidence suggests they may be a product of the processing of foods. The lack of such drug-like effects from foods in their natural state supports this contention. For example, when comparing refined and unrefined carbohydrates it becomes clear that natural foods do not elicit addictive properties. Legumes, fruits, vegetables and whole grains products are not addictive and consumption of these foods is not associated with obesity. However, removal of the fibre and micronutrients from these foods alters their digestive and metabolic properties and it may be these changes that are able to elicit their possible addictive effects. Of course drugs present within foods, such as caffeine, may also be a cause of addiction. However, these are because of the effects of the drug, and are not drug-like effects of foods. Therefore the addictive properties of foods such as tea and coffee should not be confused with drug-like properties of refined carbohydrates in foods, the latter being a less understood concept.
The Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) defines addiction and these definitions are able to be applied to foods in some cases. According to the DSM-IV, for addiction to be present there should be signs of tolerance, withdrawal symptoms and an increasing intake of the substance within 1 year. One study has assessed the definitions of addiction regarding foods, and using previous studies has reviewed the evidence for the addictive nature of foods1. The opinions of the authors were that refined carbohydrates and sugar may cause addiction and this may explain the role of these foods in obesity. The authors also noted that initially the addictive properties of alcohol and nicotine were both dismissed, and their addictive nature took decades to reach acceptance. It is therefore not surprising that addiction to refined foods may be dismissed, especially by those with a vested interest in the sale of such foods. In this regard ignoring the opinions of the men in expensive suits that represent the food industry is probably a good idea.
RdB
