What's in food?

How is our nutrition adding to our waistlines? iVillage investigates food, product labelling and the way we eat

With an increase in the accessibility and variety of palatable foods in the UK, coupled with our couch potato mentality, it seems that the odds of becoming obese are stacked against us. Growing rates of obesity are linked to unhealthy food choices; an increased consumption of refined grains, fat and added sugars.

As countries become more affluent, there is an increased tendency to have a lower consumption of fruit and vegetables and for a higher value to be placed on meat and dairy foods. This can have serious negative consequences on our health.

The problem with fat

Around 35 per cent of energy comes from fat in the UK diet. International organisations such as the Department of Health, World Health Organisation, and the World Cancer Research Fund agree that eating too much fat, particularly saturated fat, can increase our risk of developing heart disease, diabetes and some cancers.

How has our diet evolved from being low-fat, high-fibre containing plenty of fruit and vegetables to one that is high-fat and low in refined grains? Fat as a concentrated energy source is often valued higher than healthier options despite the availablity of fresh produce. Plus, fattier food is cheaper in comparison. It hasn't been clearly established that humans actually have an innate preference for fat; the only known inborn taste preference is for sweetness.

According to research by Birch, an American psychologist, preferences are learned during childhood by seeing what adults eat. It is also known that repeated consumption of high-fat foods can reinforce our liking for them and cause us to overeat. Plus, we eat more calories than we can burn off as a result of our sedentary lifestyles because high-fat foods are energy dense.

Energy density

Fat is energy-dense: weight-for-weight it contains twice as many calories (9 kcal per gram) as carbohydrates or protein (4 kcal per gram). Our appetite control systems can't seem to differentiate between eating high-fat and low-fat foods.

Studies in the American Journal of Clinical Nutrition published in the 1990's have demonstrated this phenomenon of bingeing on fatty food. When volunteers are offered foods that had been secretly manipulated to alter their fat content, they serve themselves the same amount of foods whether they're offered a low- or high-fat meal. So volunteers consumed more energy per forkful without realising it.