An Investigation of Summer Weight Change in Elementary School Students
prevention efforts in the United States have focused primarily on the school
environment, yet emerging research indicates that many children gain weight more rapidly
during the summer than the school year. This phenomenon appears to more strongly affect
children who are already at greater risk for adult obesity: those who are black or
Hispanic, and those who are overweight o... read morer obese. For this reason, excess summer weight
gain has the potential to exacerbate health disparities and negate the strides made by
school-based obesity prevention programs and policies. Our understanding of the primary
causes of excess summer weight gain and the extent to which it occurs is limited. The
goal of the research was to determine whether excess summer weight gain occurred in a
population of low-income, ethnically diverse schoolchildren, and to explore potential
causes. These goals were achieved through the following specific aims, all of which
focused on an at-risk sample of third and fourth grade students from the FLEX Study, a
randomized-controlled trial to evaluate the impact of school-based physical activity
programs: 1) to explore qualitative differences in daily routine, eating habits, and PA
between summer break and the school year; 2) to compare the rate of change of BMI during
the school year and summer break, and explore differences by race/ethnicity and weight
status; and 3) to evaluate differences in PA and dietary patterns between school year
and summer break. For Study Aim 1, we conducted 28 interviews with parents of third and
fourth graders participating in the FLEX Study. The findings suggest room for
improvement in diet quality, sleep patterns, and screen time during the summer months.
They also highlight the need to address unique summertime stressors on families -
particularly limited access to affordable childcare and summer programs. For Study Aim
2, we used mixed linear models to compare change in BMI across a school year and summer
interval in an ethnically diverse sample of 769 FLEX students. On average, children in
this sample gained weight more rapidly during the summer interval (β=0.046 kg/m2
per month, p=0.007). We did not observe any statistically significant differences in
summer weight gain across racial/ethnic groups or weight classes, but we did observe a
significant difference across FLEX intervention groups (χ2=14.90, p<0.001).
Children in the control and classroom activity break groups gained BMI at a faster rate
in the summer, while children in the walk/run group did not. For Study Aim 3, we
assessed and compared school year and summer diet and physical activity patterns in a
sub-sample of FLEX students. Children (n=105) consumed significantly fewer daily
servings of vegetables (β=-0.49, p=0.009), salty snacks (β=-0.58,
p<0.001), and sweets (β=-0.47, p=0.049) in the summer than the school year.
Children engaged in 12.8 fewer minutes of moderate-to-vigorous PA (p=0.010), 113 fewer
counts per minute of total PA (p=0.019), and 26.5 more minutes of sedentary behavior
(p=0.018) in the summer. In summary, these findings show that excess summer weight gain
is a concern for urban schoolchildren in Massachusetts, and that physical inactivity is
likely an important contributor. Qualitative interviews also suggest room for
improvement in children's summertime sleep patterns, screen time, and diet quality.
Strategies are needed to increase opportunities for PA engagement and ensure access to
healthy meals. Areas for future research include characterizing community-level
influences on summer health and developing interventions to prevent excess summer weight
gain and help sustain the effects of school-year
Thesis (Ph.D.)--Tufts University, 2017.
Submitted to the Dept. of Food Policy & Applied Nutrition.
Advisor: Jennifer Sacheck.
Committee: Kenneth Chui, Jeanne Goldberg, and Aviva Must.
Keyword: Nutrition.read less