For many of us the consequences of leading an unhealthy lifestyle aren't good.
The effects lie deep beneath the surface in the form of toxic fat.
For a long time, fat (adipose tissue) was simply seen as the body's way of storing extra energy. It was assumed that fat was stored just below the skin and was harmless. We now know that fat is stored throughout the body and that it produces chemicals which can be toxic to the body.
The link between the way body fat is distributed and the risk of disease was first suggested in the 1950s, when it was seen that people with upper-body (abdomen) fat were more likely to develop type 2 diabetes and heart disease when compared to people with fat stored in the lower body (hips). It was not until much later that this idea became more widely accepted. In the 1980s, it was reported that waist-hip circumference was more strongly associated with heart disease and death in men than BMI (body mass index). Waist-hip circumference and waist circumference are now recognised as a reasonable way of measuring abdominal (or visceral) fat.
Waist measurement is a better predictor of health risks than BMI. A larger waist contributes to the metabolic syndrome and is a risk factor for type 2 diabetes, heart disease and some cancers (including cancers of the oesophagus, pancreas, bowel and breast).
The science behind how obesity-related diseases develop is complicated but it is agreed that the chemicals released by fat are to blame. We no longer think of fat as just storage. Energy is stored in fat cells (adipocytes), but fat tissue also contains many other types of cells, all of which release chemicals.
Fat tissue is now thought of as an endocrine organ, which means it releases chemicals into the body. There is a pretty clear link between the amount of fat a person has and the levels of these chemicals in the body. So what is it about visceral fat (the fat surrounding your internal organs) that makes it cause so many diseases?
A number of theories have been put forward to explain the effects visceral fat has on the body, and to date there is not much agreement but one thing is certain - visceral fat is a good indicator of whether someone is at a higher risk of disease and weight loss results in a loss of visceral fat.
Learn about chronic diseases and the link between overweight and obesity.
Not all body fat is bad
While too much body fat (particularly visceral fat) is harmful, we all need some fat for good health. That's why LiveLighter talks about achieving and maintaining a healthy weight, rather than focussing on weight loss.
Being underweight also carries serious health risks.
Body fat plays a number of very important roles in the body, and it’s not just an energy store, cushioning and insulation from the cold. The body needs fat to make body cells (membranes) and hormones (chemical messengers). Fat is also a store for some vitamins and minerals and is vital for your nerves to work properly. Just like being overweight, the risk increases as a person moves further from a healthy weight.
People who are underweight should talk to their doctor or relevant health professional.
If you're concerned about a loved one, or for more information about eating disorders and where to seek help, please visit www.nedc.com.au.