Seasonal variability in weight change during elementary school

Obesity (Silver Spring). 2015 Feb;23(2):422-8. doi: 10.1002/oby.20977. Epub 2014 Dec 31.


Objective: To examine seasonal variation in weight gain across elementary school (kindergarten-5th grade) among children who are healthy weight, overweight, or obese and from different racial and ethnic groups.

Methods: The sample included 7,599 ethnically diverse students ages 5-7 years at baseline (Caucasian: 21.1%, Black: 36.2%, Hispanic: 26.0%, Asian 16.7%). Heights and weights were measured by school nurses at the beginning and end of each school year from kindergarten through the beginning of 5th grade.

Results: Beginning the summer after 1st grade, all children demonstrated a pattern of standardized BMI (zBMI) increases during the summer (0.04 to 0.09) and zBMI decreases across the school years (-0.06 to 0.00; P<0.0001). Hispanic children and children who were overweight and obese exhibited this pattern in kindergarten while children of other ethnicities and with a healthy weight did not (P<0.0001).

Conclusions: Beginning the summer after 1st grade, a consistent pattern of relative weight gain during the summer months (Δ in BMI percentile=1.04) and weight loss during the school year (Δ in BMI percentile=-0.34) emerged. This pattern appeared earlier for children who were overweight, obese, or Hispanic. These findings suggest a need to better understand the causes of the problematic increases in weight during the summer.

Publication types

  • Multicenter Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Body Weight / physiology*
  • Child
  • Child, Preschool
  • Ethnicity*
  • Female
  • Follow-Up Studies
  • Humans
  • Male
  • Obesity / ethnology*
  • Obesity / physiopathology
  • Overweight / ethnology*
  • Overweight / physiopathology
  • Prevalence
  • Retrospective Studies
  • Schools*
  • Seasons*
  • Students
  • Texas / epidemiology
  • Weight Gain / physiology*