Over the past century, we have seen substantial changes in food dynamics and a variety of trends that have influenced our decisions. For example, we have witnessed cholesterol, dietary fat, carbohydrates and most recently, sugar vilified. The field of nutrition is relatively young and coming up with reliable studies is very challenging. A narrative review published by the British Journal of Sports Medicine on August 23rd, 2017 claimed that sugar produces enough symptoms to be considered as an addictive substance in animals. This review was then picked up by the media and in typical fashion was taken out of proportion and went viral. These days, most self-proclaimed health gurus, gym trainers, and some medical doctors have launched a war on sugar. However, do we have enough evidence to claim that sugar is indeed as addictive as cocaine?
To answer this question, we must take a look at the original text and assess the validity of its claims. Firstly, it has to be clarified that this was not a clinical trial nor a meta-analysis. It was a narrative review which tend to be notorious for flaws. The authors cited several rat trials and studies showing the neurochemical pathways involved with sugar consumption and metabolism. Animals trials are good models but are not bulletproof and cannot be extrapolated like what was done in that review. To put it into perspective, this narrative review has been officially picked up by 39 news. To the ordinary citizen, a statement like “sugar is more addictive than cocaine” (DiNicolantonio, O’Keefe, & Wilson, 2018) is bold and worrisome. Although such claims are bold, do we have epidemiological studies proving otherwise?
On the 1st of July 2017, a cross-sectional study in Appetite was conducted studying eating dependence and weight gain in 1495 university students from different faculties. The students were assessed for DSM-related signs of food addiction for particular food categories (Yale Food Addiction Scale) and correlated with BMI. From that total sample, it was found that 95% of the participants experienced at least one symptom of food dependence. 12.6% of the participants met the YFAS classification or “food addiction” under the DSM-IV criteria. 30% experienced these symptoms with high-fat savoury foods, 25% with high-fat sweet foods, 2% for fat/savoury foods and 5% mainly sugar-containing foods. “An overweight BMI correlated only with addictive-like problems for high-fat savoury and high-fat sweet foods (P < 0.0001), while this was not found for foods mainly containing sugar.” (Markus, Rogers, Brouns, & Schepers, 2017)Despite it being performed on humans, this study is not flawless. The participants completed an online survey, and their answers were then analyzed statistically. Surveys do not account for cognitive biases, and self-reporting has been shown to be unreliable.
A review in the journal of clinical nutrition assessed the plausibility of sugar addiction and its role in obesity and eating disorders. The review concluded that there is no support from human literature for the hypothesis that sucrose may be addictive or play a role in eating disorders. However, like with all literature reviews, we must assess the validity of the literature studied. The review commenced by addressing the studies done on rodents and presented the flaws of basing claims on rat models. “Although animal studies can generate hypotheses, they need to be confirmed in humans who in addition are influenced by a cultural and social environment that adds a complexity not seen with rodents.” (Benton, 2009)It has to be mentioned that the rat studies deprived them of food for 12 hours and then gave them other 12 hours of free eating and that feeding pattern was enforced for a month. With such feeding patterns, binge eating patterns are inevitable. This review is much more rigorous in terms of science and the validity of the literature. But it has to be noted that although the author is not affiliated with any sugar production corporations, this review was partially funded by the World Sugar Research Organization.
In conclusion, although bold claims like, sugar is more addictive than cocaine” generate a lot of internet clicksand go viral, we must be increasingly skeptical of such claims and dig for evidence. Rat trials are a good way to test a hypothesis and potentially open windows for human clinical and epidemiological trials, they are not enough to come up with claims that could incite fear in the general public. The field of nutrition is rapidly changing, and solid evidence is hard to come by. Despite the flaws in the rat trials, it can be said that properly controlled double-blind human trials are required to prove or disprove the propensity of sugar or any other food to be addictive for the matter. As of right now, the evidence is limited, and we must wait for more research.
Written by: Anas Hourani; U1 Concurrent Food Science and Nutrition