It is difficult to prevent and treat overweight and obesity

Most population-based prevention programs that have been scientifically assessed have not demonstrated any favourable effects on the prevalence of obesity. However, there are examples of successful programs for both adults and children.

According to the Swedish systematic review of interventions (Asp et al., 2002), scientific assessments of treatment methods for obesity show that:

• Changes in dietary habits through counselling can lead to weight reduction in the range of 3 to 10 kg during the first year (or 10% of body weight in children). The long-term effects are uncertain.
• Regular exercise contributes to weight reduction.
• Behavioural therapy in conjunction with changes in diet and exercise can have further effects on weight if supportive interventions continue for a longer period.
• Treatment based on the ‘Weight Watcher’ approach often results in a permanent weight loss of 10% or more of their original weight.
• VLCD for 6 to 12 weeks yields a greater weight reduction than conventional low energy diets. In studies of VLCD for 1 to 2 years (often periodic), a retained weight loss of a few kilograms more than in treatment using a balanced diet alone was noted.
• Pharmacological treatment using orlistat (Xenical®) or sibutramine (Reductil®) yields an average weight loss of 2 to 5 kg beyond what would be attained through diet and exercise alone. In clinical trials, one fourth to one fifth of those who started pharmacological treatment lost at least 10% in weight compared to half as many of those treated with placebo.
• The scientific evidence for a wide range of alternative medicine methods is too weak to draw any conclusions concerning the possible effects these methods have on obesity.
• Usually weight loss is not permanent. Within a few years most who had initially succeeded in losing weight had returned to their original weight. Therefore, it is particularly important to develop and assess long-term treatments that aim at permanent weight loss.
• Surgical treatment is an option in severely obese patients. On average, it reduces weight by more than 25% (e.g., from 125 to 90 kg) up to 5 years after surgery. After 10 years, a weight loss of approximately 16% remains, on average slightly over 20 kg. This has substantial health and quality of life benefits for the patient. The intervention, however, carries risks of complications.

Environmental interventions need to be developed

Although many environmental factors have been cited as contributing to obesity, there have been few controlled studies showing that changes in these factors will prevent weight gain. Environmental interventions attempt to modify the external surroundings with a goal of affecting behavioural changes, such as improvement in diet, increased physical activity, and or decreased sedentary behaviours. The aim of such interventions is to prevent weight gain, without exclusive reliance on an individual’s knowledge or motivation.

Examples of environmental interventions include:

• Providing safe walking or cycling routes in the context of a “walk/cycle to school” campaign;
• Offering smaller portion sizes, at lower prices, in restaurants, cafeterias and/or vending machines;
• Providing access to bicycle racks, lockers, showers, and other incentives to encourage cycling to work or school and physical activity during the workday;
• Making stairways more accessible and attractive, through lighting, signals and open access, while discouraging the use of elevators.

An integrated approach is recommended

In 2005, the Heart and Stroke Foundation of Canada made an inventory of interventions related to obesity (HSF, 2005). They concluded that public health approach to disease prevention should not focus solely on risk behaviour education and behavioural skill development. It should also incorporate environmental and policy measures, plus an understanding of the barriers preventing behaviour change. Efforts to develop the next generation of preventive interventions must focus on building relationships with communities and develop interventions that derive from the communities’ assessments of their needs and priorities (HSF, 2005).

Several authoritative bodies have published a range of opportunities for intervention related to obesity. A short review is presented in Opportunities for interventions.