A standardized educational intervention ameliorates deleterious effects of mandatory service on lifestyle habits in...

Obesity has emerged as a formidable global health challenge and health related complications affect both the civilian world and military readiness. While lifestyle is known to play a crucial role in the development of obesity, the effects of lifestyle interventions depend on the setting and cultural background and their effectiveness has remained largely unsatisfactory. We here report on an educational intervention study in Austrian conscripts undergoing their mandatory service with the aim of assessing nutritional habits and changes in body composition.

We performed a cluster-randomized controlled trial in two companies of conscripts of a Guards regiment in Austria. 173 male subjects (85 in the intervention group, 88 controls) completed the study protocol. The intervention group received 15 h of an education-based standardized lifestyle intervention within the first month of their service. Assessed outcomes included changes in body composition measured through bioimpedance analysis, the alternate healthy eating index (AHEI), calculated from a self-reporting FFQ and changes in nutrition knowledge assessed through a validated questionnaire. Subjects were followed up upon until the end of their 6-month service period, at which time final assessments were taken. Linear regression models were applied to assess the effect of the intervention over time.

The intervention group exhibited a lower mean increase in BMI (+ 0.68 ± 0.17 vs. + 2.33 ± 0.34), bodyfat percentage (+ 0.15 ± 0.99 vs. + 1.59 ± 0.75) and fat mass index (+ 0.14 ± 0.30 vs. + 2.33 ± 0.38) with a significant intervention effect over time. Alternate Healthy Eating Index showed a significantly smaller decrease over time in the intervention group (-0.20 ± 7.19 vs. -4.45 ± 8.03) while nutrition knowledge showed a significantly greater increase in the intervention group over controls (+ 0.17 ± 0.15 vs. + 0.02 ± 0.13).

We demonstrate, to the best of our knowledge for the first time, the effectiveness of an educational intervention aimed at improving lifestyle behavior in the setting of mandatory service. Additional research will be required to confirm our findings in other cohorts and to assess possible long-term benefits of such programs.

The study has been registered with ISRCTN under the reference number ISRCTN13067220 (date of registration: 19.09.2025).