Obesity (body mass index of more than 30 kg/m2) and overweight (body mass index of 25 to less than 30 kg/m2) are increasingly important public health issues, and contribute to serious health problems and extensive economic costs worldwide. Body mass index is a common measure used in classifying overweight and obesity in adult populations and individuals, and is conforming to the World Health Organization (WHO) standard. It is defined as the weight in kilograms divided by the square of the height in meters.
Generally, weight loss programmes tend to involve diet and physical activity interventions. The 'Stages of Change' (SOC) model can be used as a framework to plan these interventions in both hospital and community settings. SOC describes the five stages an individual goes through when changing from an unhealthy behaviour to a healthy one. SOC is fundamental to what is known as the 'Transtheoretical Model' (TTM), whereby an individual's readiness to change is assessed. In this review, we assessed the use of the TTM SOC in weight management programmes for overweight and obese adults, in terms of the effects on weight loss and dietary and physical exercise behaviour change.
Five trials were included in the review and 3910 participants were evaluated, with 1834 participants randomly allocated to intervention groups and 2076 to control groups. The trials varied in length of intervention (from 6 weeks to 24 months), with a median length of nine months. The use of TTM SOC resulted in minimal weight loss (about 2 kg or less) and there was no conclusive evidence for sustainable weight loss amongst participants. However, other significant positive outcomes were noted, such as a change in physical activities behaviour and dietary intake. Weight gain was among the adverse events reported.The trials did not report other important outcomes such as health-related quality of life, morbidity and cost. The impact of TTM SOC in weight loss management may depend on how it is used in combination with other strategies and thus further rigorous research is required into this potentially valuable interventional strategy.