The H2020 "NoHoW Project": A Position Statement on Behavioural Approaches to Longer-Term Weight Management

Abstract

There is substantial evidence documenting the effects of behavioural interventions on weight loss (WL). However, behavioural approaches to initial WL are followed by some degree of longer-term weight regain, and large trials focusing on evidence-based approaches to weight loss maintenance (WLM) have generally only demonstrated small beneficial effects. The current state-of-the-art in behavioural interventions for WL and WLM raises questions of (i) how we define the relationship between WL and WLM, (ii) how energy balance (EB) systems respond to WL and influence behaviours that primarily drive weight regain, (iii) how intervention content, mode of delivery and intensity should be targeted to keep weight off, (iv) which mechanisms of action in complex interventions may prevent weight regain and (v) how to design studies and interventions to maximise effective longer-term weight management. In considering these issues a writing team within the NoHoW Consortium was convened to elaborate a position statement, and behaviour change and obesity experts were invited to discuss these positions and to refine them. At present the evidence suggests that developing the skills to self-manage EB behaviours leads to more effective WLM. However, the effects of behaviour change interventions for WL and WLM are still relatively modest and our understanding of the factors that disrupt and undermine self-management of eating and physical activity is limited. These factors include physiological resistance to weight loss, gradual compensatory changes in eating and physical activity and reactive processes related to stress, emotions, rewards and desires that meet psychological needs. Better matching of evidence-based intervention content to quantitatively tracked EB behaviours and the specific needs of individuals may improve outcomes. Improving objective longitudinal tracking of energy intake and energy expenditure over time would provide a quantitative framework in which to understand the dynamics of behaviour change, mechanisms of action of behaviour change interventions and user engagement with intervention components to potentially improve weight management intervention design and evaluation.

Keywords: Behaviour change; Energy balance; Weight loss; Weight loss maintenance.

Fig. 1

Adaptation of the NIH Working Group Report framework for maintenance of weight loss (WL) to show how changes in energy balance physiology and behaviour potentially undermine longer-term weight management interventions. The study on weight management tends to be split into small-scale physiological studies of WL and the larger-scale interventions that seek to understand mechanisms of action of behaviour change approaches, and there is an urgent need to integrate these fields of study. EI, energy intake; EE, energy expenditure.

Fig. 2

In many interventions, outcome measures are made during constrained time windows at a small number of regular stages at the beginning, middle and end of the intervention.

Fig. 3

Schematic adaptation of the NIH Working Group Report framework for maintenance of weight loss illustrating how pretreatment predictors and mechanisms of action of behaviour change interventions relate to compensatory changes in the components of energy intake (EI) and energy expenditure (EE). At present, moderators, mediators of energy balance behaviours and energy balance behaviours themselves all tend to be assessed using self-report measures. Objective tracking of estimated energy intake, expenditure and balance would provide an empirical framework in which to examine psychosocial predictors of longer-term weight outcomes. WLM, weight loss maintenance.

Fig. 4

Schematic diagram illustrating how quantified user engagement with intervention components (using meta-data) can be related to cause-effect models elucidating mechanisms of action of behaviour change interventions in the context of quantified energy balance physiology and behaviour. WLM, weight loss maintenance; EI, energy intake; EE, energy expenditure; ΔES, change in energy stores; Δt, change in time.