Beat Obesity with Smart Foods
Victoria Trowse looks into whether 'smart foods' hold the key to beating obesity
Are you trying to lose weight? Do you ever wish you could eat less but still feel full?
Scientists hope they can create foods that will trick the brain into thinking the gut is full. Full4Health, the latest research in the fight against obesity, is a 5-year collaborative project across Europe which aims to reveal the mechanisms of hunger and satiety, and the effects that food has on these processes. By decoding the satiety signals that the gut sends to the brain, it might be possible to devise ‘smart foods’ designed to communicate feelings of fullness to the brain, and thus help fight obesity.
Obesity is a major public health problem across the developed and developing world. Worldwide obesity has more than doubled since 1980. According to estimates for 2008, over 50% of both men and women in Europe were overweight, and approximately 23% of women and 20% of men were obese. In the UK, just over a quarter of adults (16 or over) were classified as obese in 2010. Around three in ten boys and girls (aged 2 to 15) were classed as either overweight or obese.
Fundamentally, overweight and obesity occurs when calories ingested as food and drink exceed calories expended through metabolism, thermogenesis and physical activity. These excess calories are stored as body fat (adipose tissue). Obesity greatly increases the incidence of diseases that have a major impact on longevity and quality of life, such as type 2 diabetes, heart disease, hypertension, and cancer.
Although there are a number of drugs for the treatment of obesity, the recent withdrawal from use, due to unacceptable side effects, of two major products (Rimonabant in 2009 and Sibutramine in 2010) has prompted scientists to attempt to develop dietary strategies, and specifically a food solution, to address obesity. Since obesity is primarily driven by over-consumption of calories, the potential to manipulate the mechanisms of hunger and satiety through diet is particularly relevant to any strategy to prevent obesity and overweight.
Furthermore, to date, gastric bypass surgery is the only reported medical intervention providing substantial long-term weight loss for most patients who are severely obese. Not only does it cause weight loss, but there is also a dramatic remission of type 2 diabetes. The resolution is almost instantaneous, indicating that mechanisms other than weight loss itself are responsible. The mechanisms have not yet been fully established, but it appears that altered gut hormone levels after surgery may play a role. This has turned the focus towards appetite-regulating hormones in the gut.
What if the same results could be achieved without surgery? We already know that nutrients from food and drink interact with gut cells, which send chemical messengers – satiety hormones such as cholecystokinin (CCK) and glucacon-like peptide 1 (GLP-1) – to the brain to signal that the stomach is full. However, more research is needed to determine which specific nutrients are involved, whether it is possible to manipulate how food interacts with those signalling systems and how those systems are integrated at different levels in the brain. 
The research stands out from similar previous studies by focusing on males and females, lean and overweight people, from four age groups: children, teenagers, adults and the elderly. “If we are looking to reformulate foods to come with additional benefits built into them, those reformulations will likely vary in different groups,” says Professor Julian Mercer, Full4Health project coordinator. So no one size will fit all.
But could ‘smart foods’ really beat obesity? Some argue that its chance of success may be limited because feeling satiated does not necessarily stop people from eating. Satiety is a complex interaction between internal satiety signals, other food benefits and environmental cues such as health labels, portion size, convenience, perceived variety and the presence of others. This interplay between internal signals of hunger and satiety and external signals makes it very challenging. 
Both projects are still in their early stages so it might be a while until ‘smart foods’ are available in your local supermarket. Until then, trick your body into thinking it is full by including plenty of low energy density foods, such as fruit and vegetables, and fibre rich foods as well as some lean protein in every meal. And remember to eat slowly – research has shown that it can take up to 20 minutes for ‘full up hormones’ from your gut to give your brain the ‘stop’ signal. But most important of all, go with your gut feeling!
1. Full4health Project. http://www.full4health.eu/project/
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