4. THE SCALE OF CHANGE REQUIRED
4.1 The challenge for Scotland is to make significant cross-portfolio investment leading to fundamental change in the environmental, social and cultural circumstances under which people continue to become more overweight and obese. Our policies need to be directed at supporting people to achieve and then maintain a healthy weight. Given that the majority of the Scottish population are already overweight or obese and will only become more so over the coming years, this will in practice mean policies directed at sustained weight loss for affected adults and children growing into a healthy weight. This is a considerable challenge as illustrated by the scale of change required.
Improving our diet
4.2 The dietary goals re-affirmed in the National Food and Drink Policy ( Appendix 4) are appropriate targets at a population level for achieving nutritional balance and protecting health across a broad range of risk factors in the long term. However, they were not directed towards tackling obesity in themselves and they do not provide guidance for the achievement or maintenance of weight loss.
The degree of overweight or obesity is determined by the degree to which an individual is in positive energy balance over a sustained period ie energy intake exceeds energy expenditure. Therefore, a small persistent positive energy balance over a relatively long period of time can result in obesity. It is estimated that the average adult man in Scotland consumes more than 54,000 excess calories every year (average of 148 excess calories a day) and the average woman consumes more than 33,000 excess calories per year (average of 90 excess calories a day). 14
Increasing our physical activity levels
4.3 Recent evidence has shown that physical activity has a limited role in the development of obesity. 15 The physical activity recommendations in Let's Make Scotland More Active are important in protecting against many serious illnesses in the long-term, but they will not secure the achievement or maintenance of healthy weight loss. We also know that sedentary behaviour 16 makes an additional contribution to weight gain. Therefore, to achieve a healthy weight it is important that we both participate in enough activity, and that when we are not doing this we are careful to minimise how much time we spend sitting down, for example, in front of the television or computer. In addition, there is evidence 17 that weight gain is linked to watching television not simply because we are sedentary and more likely to be snacking while doing so, but also because while we watch television we are exposed to more advertisements for unhealthy food and drink which influences our behaviour.
4.4 To achieve sustained weight loss, for the majority of Scotland's population who are already overweight, requires both a change in eating habits to reduce calorie intake and an increase in physical activity. For adults, at least 60 minutes of moderate activity, such as walking, is required on most days of the week to both lose weight and maintain weight loss. 18 The current reality is that the majority of the population take less than the recommended physical activity levels (30 minutes of moderate activity) which is sufficient only to maintain their existing weight.
4.5 The scale of change required for both diet and physical activity to reduce obesity across the population cannot rely on individual behaviour change alone. We need to act at the population level so that these changes become the norm in Scottish society.
4.6 There is little evidence of such society-wide change from across the world which can be used to guide a cross-government approach, although this is an aspiration in the majority of OECD countries. 19 Societies that have achieved significant decreases in obesity rates, such as Cuba, 20 have done so because of catastrophic economic events, rather than as an aspiration to improve the health and economic wellbeing of the country.
4.7 The Foresight report is clear; if we are serious about challenging rising obesity levels then we need to recognise that isolated or partial activity in one or two policy areas is futile. This is not simply because of the scale of the challenge, but also because of the complex inter-dependency of the factors influencing obesity. This means that an intervention in one part of the system alone risks a counterproductive effect elsewhere in the system. For example:
- At a biological level our bodies are designed to conserve energy if we simply start to consume fewer calories. Efforts to support healthy eating must be complemented by opportunities to expend more energy.
- At an environmental level we can also imagine how increasing walkable pedestrian areas in our town centres, without parallel actions to influence the kinds of high calorie snacks and drinks offered by cafes, takeaways and convenience stores could have the opposite outcomes to those we intended by increasing exposure to energy-dense foods and drinks.