Slow down on blaming fast food

When we hear ‘fast food’, one of the first things we probably think to ourselves is ‘unhealthy’. Accompanied with the term unhealthy is the unsettling statistics of obesity in the United States—34.9% or 78.6 million. The three terms, ‘fast food’, ‘unhealthy’, and ‘obesity’ do not seem to be mutually exclusive since statistics show that overweight and obese people tend to favor unhealthy food choices, like those at fast food restaurants, more often than healthy people (2, 3). However this social stigma is attached to the population, we cannot escape the ideology that fast food consumption (FCC) is inextricably linked to unhealthiness and obesity, no matter how many times it is replicated in research. The reality is that fast food restaurants are here to stay and as long as there are consumers who prefer taste over function, they will continue to exist.

Although the numbers are frightening, research is beginning to focus more on how public policy can get people to accept fast food consumption rather than ostracizing it, and potentially ostracizing consumers in the process. One such research study is Poti et al’s study on how fast food consumption reflects poor dietary outcomes of children. They sought to evaluate not how FFC may be independently linked with poor health outcomes, but how FFC influences other dietary choices. In other words, they wanted to look at the overall picture of diet. Their introduction stated what previous research has, children who were frequent fast food consumers had higher total energy intake; had lower fiber intake; and consumed diets higher in energy density than their counter-parts. In general, fast food consumers had an overall poorer diet quality compared to non-consumers.

The authors’ hypothesis is in line with previous research done on adults and FFC, and its effects on correlation with other dietary factors. Specifically, they wanted to study this relationship in children since according to them, a study on this has never been done before. They pointed out that previous literature did not control for confounding variables and that “public health efforts targeted at fast food might be overstated as well” (3). As such, their intention is to “determine whether fast food consumers (children) also eat poorly outside of the fast food restaurant and to compared the independent associations of FCC compared with dietary pattern for the remainder of intake with overweight/obesity prevalence and dietary outcomes” (3).

Not surprisingly, the authors found that high-consumers (HC) ate significantly less dairy and more sugar-sweetened beverages, not only while eating at fast food restaurants, but also outside of them compared to non-consumers (NC) and low-consumers (LC). HC also had lower intake of fruits and vegetables, though the between-group differences did not reach statistical significance. In conclusion, the authors’ findings reinforce previous findings that FCC is significantly associated with overweight/obesity. However, the twist here is that once the remainder of diet is factored in, the association disappears and remainder of diet continues to be significantly associated with overweight/obesity.

Study design and research methods

Researchers used a cross-sectional analysis including 4446 US children aged 2-18 years old participating in the 2007-2010 National Health and Nutrition Examination Survey (NHANES) and its dietary interview component. A study of this magnitude is a huge undertaking and whatever relationship they find will surely be significant.

Dietary assessment: Two 24-hour recalls using the United State Department of Agriculture’s (USDA) Automated Multiple-Pass Method by trained interviewers

  • 1st: Day 1 in person
  • 2nd: 3-10 days later by phone

Anthropometric measurements and covariate assessment: In-person interviews collected demographic and socioeconomic data, including sex, age, race-ethnicity, household income, and parenteral education level. Weight, height, and BMI were measured by a physical examination and BMI calculation. BMI classification was defined using the Center for Disease Control’s (CDC) 2000 sex-specific BMI-for-age growth charts, with overweight at or above the 85th percentile but below the 95th percentile, and obesity being at or above the 95th percentile.

Other methods the researchers used were analytic sample; fast food consumption (food from a restaurant without a waiter/waitress and percent classification of FFC—non-consumers (0% of energy), low-consumers (0.1-30%), and high-consumers (>30%); food grouping (using the USDA’s Food and Nutrient Database for Dietary Studies); dietary pattern analysis for the remainder of intake (analysis of remainder of recall to determine diet quality of the stratified groups; and statistical analysis (controlled for sex, age, race-ethnicity, income, parenteral education, total energy intake, and weight status where appropriate)

What was wrong with this study?

One of the most limiting factors of this study is how the information was collected. There is need to extrapolate on how the information is collected, but this is very difficult to practically apply as there are so many food choices available to consumers. The authors attempted to account for variation in food intake for the remainder of diet using cluster analysis and weighted percentages, but I feel this is next to impossible unless the authors collected nutrition labels for everything the children ate during the study.

Additionally, using somewhat subjective assessment methods such as dietary recalls can skew results. The authors admitted that one of the main limitations of their study was the use of self-reported dietary intake. Previous research has shown that people will tend to underreport unhealthy food choices despite being in a study that is meant to report them. This is especially discernible the heavier someone is.

What do I think of this study?

I feel this study was just another drop into an ocean of research showing that what we eat during one meal or day can have an impact on how we eat in general. This study reinforces the hypothesis that low and high FCC can shape how we make food choices outside of the fast food restaurant milieu. This is not surprisingly for health professionals since through education we have intuitively realized that FCC can represent general diet. However, not much concrete evidence exist showing that what we eat outside of fast food restaurants is more strongly associated with adverse health outcomes compared to FCC. A study of this nature can help turn the tide of disfavor towards fast food restaurants.

Of course, I do not feel that this study should be used as exoneration for fast food restaurants, but merely as a way to show that the social stigma and negativity towards fast food restaurants may be unwarranted and overstated when the rest of the diet is not taken into account, which the authors underscore.

How to use this information

In terms of practicality and implementation into public health policy, I feel this study could be a Catch-22. While it does lift some culpability from fast food restaurants, there is a real possibility that the public may misinterpret this study and use it as a ticket to consume fast food without remorse. The key, I believe, is to show that fast food is not the evil we make it out to be if the remainder of the diet is otherwise healthful.

I can see this type of research being properly implemented as a psychological bulwark against guilt-associated food intake. If people are made aware that what they eat 80% of time is what determines the general state of their health, I feel they are more likely to moderate their fast food eating and see it as a treat rather than something they should completely avoid.


  1. Ogden CL1Carroll MD1Kit BK2Flegal KM1. Prevalence of childhood and adult obesity in the United States, 2011-2012. 2014 Feb 26;311(8):806-14. doi: 10.1001/jama.2014.732.
  2. Braithwaite I1Stewart AW2Hancox RJ3Beasley R1Murphy R4Mitchell EA5ISAAC Phase Three Study GroupISAAC Phase Three Study Group. Fast-food consumption and body mass index in children and adolescents: an international cross-sectional study. BMJ Open.2014 Dec 8;4(12):e005813. doi: 10.1136/bmjopen-2014-005813.
  3. Poti JM, Duffey KJ, Popkin BM. The association of fast food consumption with poor dietary outcomes and obesity among children: is it the fast food or the remainder of the diet? Am J Clin Nutr 2014;99:162-71.