Weight Gain of Service Members After Basic Military Training

Despite weight and fitness requirements, the prevalence of overweight and obesity in the U.S. military approaches that in the general population. The purpose of this study is to assess trends in anthropometric measurements shortly after military enlistment.

This longitudinal study evaluated the change in objectively measured body weight and waist circumference in the population of U.S. Air Force members who enlisted in 2012-2013 and graduated from Basic Military Training (n=49,466). Individuals were followed for 4 years or until they left the military, for a mean follow-up of 1,218 (SD=261) days. Data were collected in 2018 and analyzed in 2019.

Among Basic Military Training graduates with available and plausible baseline data (n=46,706), weight increased incrementally by a mean of 1.5-1.8 kg per year and waist circumference by 0.3-1.1 cm per year. Over the 4-year period, total mean weight gain was 6.6 (SD=7.7) kg and waist circumference increase was 3.1 (SD=6.4) cm. Male graduates gained 7.0 (SD=7.7) kg and female graduates gained 4.7 (SD=7.5) kg. Of those who stayed in the military for 4 years, 37.3% transitioned to a higher BMI category (i.e., from normal to overweight/obese or from overweight to obese), whereas 3.9% transitioned to a lower category.

Future research is needed to understand determinants of unhealthy weight gain and the association between weight gain and physical fitness among young adults embarking on a military career.