What does it mean to be obese?
Overweight and obese are deined as abnormal or excessive fat accumulation that may impair health. Body mass index (BMI) is a simple index of weight-for-height that is commonly used in classifying overweight and obesity in adult populations and individuals. It is defined as the weigth in kilograms divided by the square of the height in metres.
The World Health Organisation (WHO) defines ‘overweight’ as a BMI equal to or more than 25 and ‘obesity’ as a BMI equal to or more than 30. These cut-off point provide a benchmark for individual assessment, but there is evidence that the risk of chronic disease in some populations, such as people in Asia, increase progressively with a BMI of 22 and over.
The new WHO Child Growth Standards, lauched in April 2006, include BMI charts for infants and young children up to age 5. However, measuring overwight and obesity in children aged 5-14 years is challenging because a standard definition of childhood obesity is not appiled worldwide. The WHO is currently developing an international growth reference for school-age children and adolescents.
WHO’s global figure indicate that in 2005:
Aproximatley 1.6 billion adults were overweight
At least 400 million adults were obese
At least 20 million children under the age of 5 years were overweight. Childhood obesity is a big problem in the USA where over 35% of children are overweight
WHO futher projects that by 2015, approximately 2.3 billion adults will be overweight and more tha 700 million will be obese. Overweight and obesity were once considered to be problems of high-income countries, but there are dramatically on the rise in low-and middle-income countries, particularly in urban areas.
Causes of obesity
The fundamental cause of obesity and overweight is an energy imbalance between calories consumed and caslories expended. Global increases in overweight and obesity can be attribtued to a number of factors including:
· A global shift in diet towards increased uptake of energy-dense foods that are high in fat and sugars but low in vitamins and minerals
· A trend towards decreased physical activity due to the increasingly sedentary nature of many forms of work, changing modes of transportation and increasing
Overweight and obesity can have serious health consequences. Risk increases progressively as BMI increases. Raised BMI is a major risk factor for chronic diseases:
· Cardiovascular disease (mainly heart disease and strokes) – already, the world’s number one cause of death, killing 17 million people each year
· Diabetes, which has rapidly become a global epidemic, WHO projects that diabetes deaths will increase by more than 50% worldwide in the next 10 years
· Musculoskeletal disorders, especially osteoarthritis
· Some cancers (endometrial, breast and colon)
Childhood obesity is also associated with a higher chance of premtaure death and disabilty in adulthood. Life expectancy is reduced by an average of 14 years for obese smokers compared with non-smokers of normal weight.
More then 60% of adults in the USA are overwieght or obese. Triple-width coffins, capable of holding a 300lg body, are in increasing demand. orldwide, airlines are having to recalculate their passengers’ payload weight. There are 70 million overweight people in China and the south Pacific now has some of the world’s highest rates of obesity.
Many low- and middle-income countires are now facing a ‘double burden’ of disease. While they continue to deal with the problems of infectious disease and undernutrition, they are at the same time experiencing a rapid upsurge in chronic disease risk factors such as obesity and overweight, particularly in urban settings,
It is not uncommon to find undernutrition and obesity existing side by side in the same country, them same community and even the same household. This double burden is caused by inadequate physical activity, infant and childhood nutirtion followed by lack of physical activity and exposure to high-fat,energy-dense, micronutrient-poor foods.
Reducing overweight and obesity
Overweight and obesity, as well as their related chronic diseases, are largely preventable. At an individual level, people can:
· Achieve a healthy weight by reducing calorie intake and exercising more
· Limit energy intake from fats and shift fat consumption from saturated to unsaturated fats
· Increase consumption of fruit and vegetables, as well as legumes, whole grains and nuts
· Limit the intake of sugars
· Increase physical activity – at least 30 minutes of regular, moderate-intensity activity on most days. More activity may be required for weight
The implementation of these recommendations requires sustained political commitment. Governments, NGOs and the private sector have vital oles to play in shaping healthy environments and making healthier diet options affordable and accessible. This is especailly important for the most vulnerable in society – poor people and the environments in which they live.
The following initiatives by the food industry could acclerate health gain worldwide:
· Reducing the fat, sugar and salt content of processed foods
· Reducing portion sizes
· Introducing innovative, healthy and nutritious choices
· Reviewing current marketing practices