Fast-food restaurants have been implicated in promoting caloric overconsumption and unhealthy habits, leading to an increased prevalence of obesity. A new study published in the American Journal of Clinical Nutrition found that per capita densities of fast-food restaurants and full-service restaurants do not correlate to obesity rates in the United States.
Obesity has increased rapidly in prevalence over the last 30 years and has become a global health concern. Importantly, obesity predisposes individuals to severe chronic diseases including cardiovascular disease, hypertension and diabetes.
While obesity can be influenced by genetic susceptibility, the mode through which excess body fat accumulates is through a sustained energy imbalance in which caloric intake is greater than caloric expenditure. This can be caused by excessive food intake or lack of physical activity. It has been heavily debated whether the obesity epidemic was caused by increased television and computer use or national-level changes in food supply.
Interestingly, the increase of the obesity rate in the United States has been echoed by an increase in the number of fast-food restaurants (FFR) and full-service restaurants (FSR) across the country. The proportion of income spent at these establishments has increased over time. This is concerning because meals consumed outside of the home are generally larger and contain significantly more calories, fat, and fewer nutrients. It has been strongly suggested that FFRs and FSRs promote the overconsumption of calories and thus are a causative factor in the obesity epidemic. Previous studies have found an association between the availability of FFRs and the consumption of fast food, indicating that neighborhood exposure to FFRs increases likelihood to purchase and consume fast food.
A new study published in the American Journal of Clinical Nutrition evaluated the population-level association between FSRs and FFRs and the prevalence of obesity. Researchers used country-level data for obesity prevalence across the United States and matched it to per capita densities of FSRs and FFRs. They predicted that FFRs and FSRs would be positively linked to obesity prevalence.
Surprisingly, the researchers found that obesity prevalence was lower in areas with more FFRs and FSRs. Upon further analysis, they deduced that this relationship was due to the greater number of FFRs and FSRs in areas where individuals were more educated and wealthier. In general, higher obesity rates are observed among the poor and less educated. However, some studies suggest that individuals with middle-range income consume the most calories from FSRs and FFRs compared to those in low- or high-income families.
Several caveats of this study exist. First, the study correlated FSR/FFR establishment densities near the homes of individuals with obesity rates. However, individuals may consume calories outside their neighbouring vicinity or near their place of work, which were unaccounted for and could obscure trends. Additionally, FFRs and FSRs are not evenly distributed throughout the country and may be spatially associated with localized clusters of obesity. Lastly, at some point, adding restaurants to a neighbourhood may not increase the amount of times a family eats food outside of the home. Therefore, we cannot expect per capita densities of FSRs/FFRs to always correlate to obesity rates, or even the frequency that people eats at these establishments.
In conclusion, this study showed that variations in the densities of FFRs and FSRs do not correlate to obesity rates in the United States. This finding has important implications for policy decisions aimed at tackling the obesity epidemic. Rather than solely targeting fast-food restaurants as the cause of obesity, healthy eating within the home should be emphasized, as well as interventions to increase physical activity.
Written By: Neeti Vashi, BSc