Quasi-experimental pilot trial: 6 months follow-up of a multidisciplinary intervention for obese adults

Abstract

We evaluated the effects of a one-year multidisciplinary group intervention for obese adults (psychological training, information about healthy diet, physical exercise program). The main research question was whether participants in an intervention including volitional aspects of behaviour change (action and coping planning) become more physically active and loose more weight than participants in a motivation-only intervention. Obese persons were invited by public calls to participate and were assigned to the intervention and control group (IG n = 36; CG n = 33). Both groups received the same intervention, except that we addressed for the IG additional to motivational aspects also volitional aspects of behaviour change. Up to now, questionnaires (psychological, behavioural variables, weight) were completed at t1 (baseline) and t2 (6 months follow up). At t2, both groups reduced significantly their BMI (t1-t2 IG: -2.29, p<.001; CG -2.44, p<.001; group differences n.s.). Only the CG increased their level of action planning (t1-t2 p<.03), leading to group differences at t2 (p<.007). Both groups increased their level of coping planning, significant differences between groups occurred in favour of the CG (IG: t1-t2 p=.002; CG t1-t2 p=.001; group differences t2 p<.03). Both groups are physically active at t1 and can increase their level (hours/week) at t2 (IG t1: 2.09, t2: 2.96, n.s.; CG t1: 2.56, t2: 3.19, p<0,6; group differences t2 n.s). Up to now, findings do not confirm that the intervention with focus on action planning has better potential to evoke substantial differences in cognitions and behaviour than the motivation-only intervention.