Implications for practice and research

• Adverse associations between fast food consumption and cardiovascular health are also observed in an Eastern population.

• The role that Western dietary behaviours play in affecting health in transitional societies needs to be articulated and addressed.

Context

Consumption of fast food has increased over recent decades, accounting for as much as 40% of daily energy among certain subgroups of the US population,1 which is typically higher in total energy, saturated fats, sodium, carbohydrates and added sugars,2 ,3 and have been adversely associated with numerous health outcomes including obesity, cardiovascular disease and diabetes.4 ,5 The proliferation of fast food outlets and the increased consumption of fast food globally is of particular concern in light of this knowledge.

Findings

Frequent (≥2 times/week) Western-style fast food consumers had a significant increased risk of developing T2DM (HR 1.22, 95% CI 1.00 to 1.47, p=0.019) and an increased risk of dying from CHD (HR 1.36, 95% CI 1.04 to 1.78) compared with non-consumers. These results were strengthened in fully adjusted models, with a 27% and 56% increased risk of incident T2DM death from CHD, respectively. Extending the highest consumers to ≥4 times/week resulted in a stronger dose-response association with CHD death (HR 1.79, 95% CI 1.09 to 2.93, p for trend=0.015).

Commentary

Historically, higher consumption of a nutritional profile similar to that observed for fast foods has been linked in clinical and epidemiological studies to obesity, CHD and T2DM, but the extent to which the consumption of fast food itself is similarly associated with health is understudied. The results reported by Odegaard and colleagues begin to fill this substantial gap in the literature.

The consumption of Western-style fast foods was measured using a single dietary report. Ideally, multiple measures of intake would have been applied, allowing for more accurate representation of usual intake and for researchers to account for changes in fast food consumption over time. Furthermore, fast food intake was defined as the consumption of ‘Western-style fast foods’ (eg, hamburgers, French fries and other sandwiches) and not as the number of times eating at a fast food restaurant. Many of these foods could be obtained from a location other than a fast food place, meaning that the association in question is more accurately described as comparing health outcomes with unhealthy Western-style foods (as compared with more classic Eastern foods) and not fast food eating per se. However, given that the Singaporean population is still in the early stages of the nutrition transition, it is likely a safe assumption that these foods were obtained and eaten outside the home.

In spite of these relatively minor limitations, the study by Odegaard and colleagues, using appropriate statistical methods for examining longitudinal data, adds significantly to our understanding of the relationship between unhealthy eating and poor health outcomes by establishing temporality of the association in an understudied population. Efforts to support healthy dietary habits are especially important as access to and consumption of fast food continues to increase globally.