The United Kingdom Armed Forces are not exempt from the obesity epidemic⁽Reference Wood¹⁾. This is of concern due to the health, occupational and economic risks that it poses. In response to this problem, a nine-month healthy lifestyle intervention was implemented aboard a deployed Royal Navy (RN) warship in 2015. One component of the intervention was the delivery of a weight management programme (WMP). The present study evaluated the effectiveness of this WMP in accordance with best practice guidelines for weight management services⁽²⁾.

The delivery and content of the WMP was based on the National Institute for Health and Care Excellence (NICE) guidance for the provision of weight management services⁽³⁾. The programme was available for all members of the ship's company (n 242) who wanted to improve their health behaviours, rather than just those classified at risk of obesity related diseases according to the NICE guidelines⁽⁴⁾. Personnel with a body mass index of less than 18.5 kg.m⁻² (i.e. underweight) were not allowed to participate in the programme.

Forty-nine RN and Royal Marines personnel (males 84 %, females 16 %), mean (SD) age 31 (7) years attended the WMP for the duration of the deployment. This equated to 20 % of the ship's company. Participants’ height, body weight and waist circumference were measured at three time points; pre-, mid- (4-5 months) and end- (9 months) of deployment.

The WMP adherence rate was 100 % (i.e. no drop outs). At pre-deployment, 45 % of participants were classified at any risk of obesity related diseases (12 % increased risk, 14 % high risk, 18 % very high risk). This reduced to 29 % at end-deployment (10 % increased risk, 14 % high risk, 4 % very high risk). There was a significant decrease in (mean [SD]) weight (91.8 [16.6] vs. 86.6 [14.8] kg, P < 0.001] and waist circumference (93.4 [12.8] vs. 85.7 [9.8] cm, P < 0.001) between pre- and end-deployment.  Weight loss over the deployment was 5.2 [4.7] % of initial weight (P < 0.001). Weight and waist circumference reduction was greatest between pre- and mid-deployment, with smaller reductions between mid- and end-deployment. There was a medium negative correlation between relative weight loss and waist circumference reduction during the deployment and weight and waist circumference measured pre-deployment (r = 0.51, P < 0.001; r = 0.52, P < 0001, respectively). The WMP therefore appeared to be more successful for participants at higher risk at pre-deployment. At the end of deployment 65 % and 61 % of participants achieved a weight loss greater than 3 % and 5 % of their initial weight, respectively; this exceeded the Department of Health best practice guidance for Tier-2 services⁽²⁾.

The findings from the present study support that an effective WMP can be delivered in a deployed military environment. Support should be offered to all personnel as prevention, rather than just being available as treatment to those classified at risk of obesity related diseases.