Global Obesity Reading Answers

The world is currently in the middle of an obesity epidemic, and though obesity is generally caused by more calories being consumed than used, there does not seem to be one underlying factor that has created the situation. There is no denying that rising incomes. The changing contents of foodstuffs calorie consumption has risen across the globe but declining levels of physical activity are also behind the problem. However, the causes are even more complicated than that. Currently 40 per cent of adults on the planet are overweight, a figure that has tripled since the 1970s. In the USA, usually considered the starting point of the epidemic, one in three adults and one in six children are obese. Obesity is measured in terms of the Body Mass Index (BMI), which is a measure of body fat using weight and height. A BMI between 19 and 25 is considered normal, over 25 is overweight and 30 or more is said to be obese.

It is not clear whether food consumption by volume has climbed over the last fifty years, but certainly the calorific density of available food has changed. Industrially processed food contains much higher levels of sugar and fat that lead to weight gain. The types of sugars involved also seem to have an impact. Timewise, the introduction of high fructose corn syrup (HFCS) into food and beverages in the 1970s correlates with the rise of obesity in the USA. Fructose is the most damaging form of sugar, as it is more difficult to break down in the digestive tract than glucose and other sugars, and is mainly broken down in the liver. This leads to fatty liver and metabolic syndrome, said to be causes of Type Il diabetes. However, the data is confusing. Sugar consumption has actually fallen in the USA, but obesity continues to rise. Though the introduction of HFCS correlates with the rise in obesity in the USA, consumption is relatively low

in the UK and Australia, and not used at all in India, yet obesity in these countries is rising.

Eating habits are changing. People in developed countries tend to snack all day, rather than eating three set meals. This has a double impact. Overall calorie consumption is higher, and the body continues to create insulin throughout the day, possibly increasing the insulin resistance that leads to a greater storage of fat in the body. The incidence is of obesity is higher in countries that are economically developed, and on the rise in countries that are developing. Statistically, development means a larger proportion of the population residing in cities. City living shows a tendency to use cars more and exercise less and there is easier access to fast, convenient and restaurant foods. However, in the USA, urban populations are 20 per cent less likely to be obese than rural populations and new studies are showing that up to 60 per cent of the rise in obesity around the world is actually in rural areas. Another inexplicable factor in

modern obesity is that it is very difficult to turn around in individuals. It seems that despite changes in diet and exercise, obesity leads to lifelong metabolic changes that force the body to maintain an undesirably high weight - most people who lose weight put it back on.

This is called yo-yo dieting. Not only do they return to their previous weights, but the weight loss induces a slower metabolism which encourages even greater subsequent weight gain. A factor at play is something that has only recently begun to be studied, and that is the changes to human gut bacteria. Certain bacteria contained in the digestive tract seem to be closely linked to obesity, however, more human studies need to be done to conclude what the best combination of gut flora is required for optimal health and weight. There is also a correlation between inflammation in the body and obesity and, particularly with the younger obese, the higher the age of the mother when born, the greater the likelihood of being overweight.

There is also a correlation between the presence of supermarkets and obesity. As they spread to developing countries, obesity rates rise. They started in the USA in the 1960s, moved to Europe in the 1970s and then there was enormous growth in them in South America and Asia in the 1990s. Now they are beginning to open across Africa, the last frontier of obesity. Is it the presence of the western diet and processed foods in these supermarkets that leads to obesity, or is it just the easy availability of cheap, high calorie food? Populations that eat the most meat are the most prone to being overweight, though it is the consumption of carbohydrates rather than protein and fats that is the currently accused nutrient group for weight gain, and meat doesn't contain carbohydrates. There is no denying that the world population is becoming more obese and this is due to modern living. However, we cannot return to the lifestyles of one

hundred years ago, so we need to pinpoint the absolute causes of this epidemic to enable populations to slim down and lead healthier lives. The race is on to discover the culprits, and it seems as though it really isn't a simple case of too many calories, not enough exercise.