Mr Epidemiology

As mothers everywhere know, breakfast is the most important meal of the day. However, as scientists, we want empirical evidence. Breakfast has been associated with several health outcomes, ranging from increased academic performance, to improved quality of life, as well as enhanced dietary profiles.

While many cross-sectional studies have found that those who skip breakfast are more likely to be obese, you cannot infer temporality from this relationship. In order to do that, you need a prospective cohort study, where you follow people forward through time to determine their weight gain.

While there are very few prospective cohort studies investigating breakfast eating habits among youth, even fewer have looked at this in Asian populations. And so Tin et al set out to look at the effect of skipping breakfast on BMI among youth in Hong Kong.

More after the jump.

What did they do?

The Student Health Service in Hong Kong provides a free annual exam to all children in all primary and secondary schools in Hong Kong. From Grade 4 onwards they also complete a self-report questionnaire on various health habits. They followed a group of students who were in Grade 4 in 1998/1999 and 1999/2000 for two years. They asked one question about breakfast habits “I usually have breakfast at ….” and the responses were: “home,” “fast food stall/cafeteria/restaurant” or “some other place.” These were categorized as breakfast eaters. There was also an option to answer “no breakfast at all.”

An interesting sub-study that they did was to recruit 101 Grade 5 youth and invite their parents to complete a questionnaire as well. They found that there was high agreement between the two (83.2%), so they could conclude that the children were answering the questions accurately.

What did they find?

They started out with 113,457 students that they could follow prospectively, but they only had complete data on 68606 (60.5%) after two years. Of all children, 5.2% reported skipping breakfast, and those who skipped were more likely to be overweight or obese; 30.7% of skippers were overweight or obese, compared to only 20.1% of those who ate breakfast regularly. They found that slightly more boys than girls skipped breakfast in Grade 4 (5.3 vs 5.1%), while the opposite was true at follow up (girls: 9.1; boys: 8.9%).

Prospectively, they found that those who skipped breakfast gained more weight than those who did not over two years (BMI beta = 0.12 kg/m2, 95% CI: 0.08-0.16). This association remained after controlling for sex, pubertal development, age and baseline BMI (BMI beta = 0.11 kg/m2, 95% CI: 0.07-0.16).

So what does this all mean?

Well, there are two things to note from this study. First, those who skipped breakfast were more likely to be overweight and obese at baseline. Second, those who skipped breakfast gained more weight than those who did not. Since youth (and adults) may skip breakfast to try and lose weight, this may be a potential behaviour healthy eating interventions can target.

And what now?

The research in this area is inconsistent at best. Some studies suggest a relationship between increased BMI gain and eating breakfast, and some do not. A Canadian study reported that children who skip breakfast and/or lunch are more likely to snack between meals, and late at night (Dubois et al.) As a result, their total caloric intake is the same as those who eat breakfast.

There are a few avenues they can pursue from here. For one, their exposure includes eating breakfast at home, and eating at a restaurant/fast food place. This could introduce error into this measure as the quality of food at a fast food restaurant is markedly different to that available at home.

Second, reasons why children are skipping breakfast can be investigated. Is it due to concerns about weight? In which case, education would be an appropriate response. Or is it due to financial constraints? If this is the case, then providing school breakfasts to children who qualify might be an appropriate strategy. However, to best utilize our limited resources, we need more information.

Tin SP, Ho SY, Mak KH, Wan KL, & Lam TH (2011). Breakfast skipping and change in body mass index in young children. International journal of obesity, 35 (7), 899-906 PMID: 21448130
Dubois, L., Girard, M., Potvin Kent, M., Farmer, A., & Tatone-Tokuda, F. (2008). Breakfast skipping is associated with differences in meal patterns, macronutrient intakes and overweight among pre-school children Public Health Nutrition, 12 (01) DOI: 10.1017/S1368980008001894