«Healthy school meals and Educational Outcomes Michèle Belot Jonathan James Department of Economics Nuffield College University of Essex University ...»
Healthy school meals and Educational Outcomes
Michèle Belot Jonathan James
Department of Economics
University of Essex
University of Oxford
This paper provides field evidence on the effects of diet on educational outcomes,
exploiting a campaign lead in the UK in 2004, which introduced drastic changes in the
meals offered in the schools of one Borough – Greenwich - shifting from low-budget
processed meals towards healthier options. We evaluate the effect of the campaign on educational outcomes in primary schools using a difference in differences approach;
comparing educational outcomes in primary schools (key stage 2 outcomes more specifically) before and after the reform, using the neighbouring Local Education Authorities as a control group. We find evidence that educational outcomes did improve significantly in English and Science. We also find that the campaign lead to a 15% fall in authorised absences – which are most likely linked to illness and health.
Keywords: Child nutrition, Child health, School meals, Education, Natural Experiment, Placebo effect JEL-codes: J13, I18, I28, H51, H52 “Mens Sana in Corpore Sano” (A Sound Mind in a Sound Body) Juvenal (Satire 10.356)
1. Introduction Children's diet has deteriorated tremendously over the last decades, and has become a major source of preoccupation in developed countries, in particular in view of the rising rates of obesity among young children, observed across almost all developed countries.1 According to the World Health Organization (2002), nutrition is related to five of the ten leading risks as causes of disease burden measured in DALYs (Disability Adjusted Life Years) in developed countries i.e. high blood pressure, cholesterol, overweight (obesity) and iron deficiency. Importantly, children’s poor diet does not only have direct negative effects on their weight and health, but also results in significant deficiencies in those nutrients playing an essential role in cognitive development (see Lambert et al. (2004)). A number of studies point at the significant and immediate effect of diet on behaviour, concentration and cognitive ability; as well as on the immune system, and therefore the ability to attend school (see Sorhaindo and Feinstein (2006) for a review).
A number of studies provide quasi-experimental evidence of a causal relationship between diet and obesity (Whitmore (2005), Anderson and Butcher (2006a, 2006b)), and in particular between the availability of junk food at school on children’s obesity.
Little is known though on the effect of poor diet on other outcomes, and in particular, on learning and cognitive ability. There are a number of studies documenting correlations between malnutrition and educational outcomes (see Pollitt (1990), Behrman (1996), Alderman et al. (2001), Glewwe et al. (2001)), but most of this literature concentrates on developing countries (and therefore on malnourishment rather than poor eating habits), and few of them are able to establish a causal effect, i.e. they do not have a source of exogenous variation in nutritional habits.
For example, in the UK, 15% of children aged 2 to 10 were classified as “obese” in 2006, compared to 10% only 10 years ago (Health Survey for England) This paper exploits a unique “natural experiment” in the UK – the “Feed Me Better” campaign lead in 2004-2005 by the British Chef Jamie Oliver aimed at improving the nutritional standards at school. Because the campaign was literally designed and implemented as a large-scale experiment, it offers a unique opportunity to assess the causal effects of diet on educational outcomes. Drastic changes to school menus were introduced in the 80 schools of one borough – Greenwich – the idea being that these schools would then serve as examples for the rest of the country.
School meals are of major importance in British schools, with about 45% of school kids in primary and secondary schools eating school lunches every day2, and are therefore an obvious instrument for policy intervention in children’s diet. In addition, school meals are part of a means-tested programme; children from less privileged backgrounds receive school meals for free. In 2006, around 18% of the entire pupil population was eligible for the free school meal programme.3 Hence, school meals provide a direct way for policy-makers to possibly reduce disparities in diet between children from more and less privileged socio-economic backgrounds, which in turn could contribute to reduce differences in educational outcomes. School meals seem also to be more important now than in the past, because children rely more on food provided at school now than three decades ago. For example, Anderson, Butcher and Levine (2003) show that increases in maternal employment rates in the US have been associated with an increase in obesity rates, which they attribute partly to the decrease in the consumption of home cooked meals.
Using pupil and school-level data from the National Pupil Database (NPD) and from the School census covering the period 2002-2007, we evaluate the effect of the campaign on educational outcomes and on absenteeism in primary schools using a difference in differences (DD) approach; comparing educational outcomes (key stage 2 outcomes more specifically) before and after the reform, using the neighbouring Local Education Authorities as a control group. We find that the campaign improved educational achievements. Our estimates show that the campaign increased the percentage of pupils reaching level 4 by 4.5 percentage points in English, and the Source: School Food Trust.
See appendix for details of eligibility criteria percentage of pupils reaching level 5 by 6 percentage points in Science. However, the estimates are not very precise, such that we cannot exclude small positive effects.
Nevertheless, it is noteworthy to find any significant effect, because the campaign was not directly targeted at improving educational outcomes and, also, we are looking at improvements within a relatively short horizon (2 years). One could have expected that changing diet habits is a long and difficult process, which would possibly only have effects after a long time, effects that would be hard to measure. Next to these educational outcomes, we find clear evidence that authorised absences (which are more likely to be linked to sickness) drop by 15% on average in Greenwich relatively to other LEAs. Interestingly, we find no such effect on unauthorised absences (less likely to be linked to sickness).
The paper is structured as follows. Section 2 discusses the existing evidence in the literature on the relationship between nutrition and educational outcomes. Section 3 describes the background of the “Feed me Better Campaign”. Section 4 presents the data and descriptive statistics and Section 5 presents the results of the empirical analysis. Section 5 concludes.
2. Related literature Despite the importance of the subject in the public and policy arenas, there are only a limited number of studies on the causal effect of children’s diet on health on the one hand, and educational outcomes on the other.
The medical literature has carried out a number of studies on the relationship between diet and behaviour, concentration and educational outcomes. Sorhaindo and Feinstein (2006) provide a review of this literature. They mention four different channels through which nutrition may affect educational outcomes. The first channel is through physical development. A poor diet leaves children susceptible to illness and in turn, greater illness results in more days of absence and thereby a decrease in teacher contact hours. The second channel is through cognition and the ability to concentrate.
Numerous studies have found a link between diet and the ability of children to think and concentrate. In particular deficiencies in iron can have an impact on the development of the central nervous system and also cognition in later life. Sorhaindo and Feinstein (2006) point out that the effects of diet on children's school performance are relatively immediate. The third channel mentioned in their review is behaviour.
For example, there is a causal link between a deficiency in vitamin B and behavioural problems; particularly related to aggressive behaviour. McCann et al. (2007) find that artificial colouring and additives resulted in increased hyperactivity in 3-year-old and 8/9 year old children in the general population. Some studies even establish a link between diet and anti-social, violent and criminal behaviour (see Benton (2007) for a review), in particular the omega-3 fatty acid DHA decreased hostility and aggression.
Behavioural problems could also spill-over on other pupils in the classroom through peer effects. The research in this area is more limited. Finally, the last channel mentioned is through school life and in particular difficult school inclusion due to obesity. Overall, the conclusion one can draw from the medical literature (see also Bellisle (2004)) is that a well balanced diet is the best way to enable good cognitive and behavioural performance at all times.
Economists have recently devoted more attention to the determinants and effects of obesity, and child obesity in particular. Anderson and Butcher (2006a) review the literature investigating the possible reasons underlying the rise in child obesity. They conclude that there does not seem to be one single determining factor of the rise, rather a combination of factors. Interestingly, they do point at the important changes in the school environment, such as the availability of vending machines in schools, as a possible factor triggering calories intake and thereby obesity. One study they have carried out (Anderson and Butcher (2006b)) link school financial pressures to the availability of junk food in middle and high schools, and estimate that a 10 percentage point increase in the provision of junk food at school produces an average increase in BMI of 1 percent, while for adolescents with an overweight parent the effect is double. Effects of this size can explain about a quarter of the increase in average BMI of adolescents over the 1990’s. Whitmore (2005) evaluates the effects of eating school lunches (from the US based National School Lunch Program) on childhood obesity. She uses two sources of variations to identify the effect of eating school lunches on children’s obesity. First, she exploits within-individual time variation in school lunch participation, and second, she exploits the discontinuity in eligibility for reduced-price lunch – available to children from families earning less than 185 percent of the poverty rate – and compares children just above and just below the eligibility cut-off. She finds that students who eat school lunches are more likely to be obese. She attributes this effect to the poor nutritional content of lunches and concludes that healthier school meals could reduce child obesity.
There are a limited number of studies studying the effect of diet on educational performance, based on interventions in the US. Kleinman et al. (2002) and Murphy et al. (1998) study the effects of an intervention providing free school breakfasts and found evidence of a positive effect on school performance. However, the evidence is limited to small-scale interventions.
A recent study by Figlio and Winicki (2005) find that schools tend to change the nutritional content of their lunches on test days. They present this as evidence of strategic behaviour of schools, which seem to exploit the relationship between food and performance as a way of gaming the accountability system. Using disaggregate data from schools in the state of Virginia, they find that those schools who are most at risk of receiving a sanction for not meeting proficiency goals, increase the number of calories of school lunches on test days. This strategy seems to be somewhat effective, with significant improvements in test scores for examinations that took place after lunch (mathematics and English). However, they argue that these changes are targeted at immediate and short-lived improvements in performance, based on an increase of the number of calories and glucose intake, rather than a long-term strategy aimed at providing a healthier and balanced diet to children.
3. Background: School Meals and the “Feed Me Better” Campaign School meals in England4 School meals were introduced at the beginning of the 20th Century in England, following a rising concern about severe malnutrition of children attending school.
Nelson et al. (2004) and Nelson et. (2006) provide an extensive report on school meals in primary and secondary schools in England, based on a survey across a representative sample of schools and pupils.
After the Second World War, the policy shifted from providing food to malnourished children to providing meals for all children. Nutritional standards were established in 1941 covering energy, protein and fat. In 1980, a change in policy occurred, removing the obligation to meet any nutritional standards. Local Authorities had discretion on the price, type and quality of meals they provided. It was not until 2001 that compulsory minimum nutritional standards were reintroduced. These standards were relatively low though and hardly enforced. A survey conducted by Nelson et al.
(2006) in the year 2005 (April to June) in England show that only 34 of the sampled 146 primary schools met all the compulsory nutritional standards. The two standards most commonly failed were “starchy food cooked in oil or fat to be available no more than three times a week” (failed by 53% of lunch services) and “fruit-based desserts to be available twice a week” (failed by 33%). The study finds that the most popular food choices among children were desserts, cakes, biscuits and ice cream (78% of pupils). Higher fat main dishes were chosen by nearly twice as many pupils (53%) as lower fat main dishes (29%), the same was true for chips and other potatoes (chosen by 48% of pupils) in comparison to potatoes not cooked in oil or fat (25%).
Overall, less than 50% of meals as chosen and as eaten met Caroline Walker Trust Nutritional guidelines for school Meals (guidelines for a balanced diet set by an expert working group) for essential nutrients such as Vitamin A, folate (B vitamin), calcium, iron, percent of energy from fat and from saturated fat.