At a recent lecture on Optimum Health given by Professor Jimmy Bell, a researcher and expert in the field of obesity, fat metabolism and their effect on human health and disease, we were presented with MRI images of bodies of various ages, shapes and sizes. The body fat was easily visible and distinguished from muscles, bones and body organs. Some fat could be located just beneath the skin (the subcutaneous fat) while other, visceral fat, lay in the abdominal area, wrapped around the internal organs – liver, heart, kidneys and pancreas and at times infiltrated the liver and spread into the muscles too. It is this internal fat that is particularly dangerous to us, as it has been linked to the increase in blood pressure, high cholesterol and heart disease as well as insulin resistance and type 2 diabetes. This type of fat is also more metabolically active, producing chemicals and hormones that can affect our mood, fertility and immune system functioning, and increase the risk of developing chronic health conditions and some types of cancers.
Surprisingly, the size, weight and BMI (the body mass index) of participants in the study was not a clear indicator of the levels of visceral fat. Some people could be thin on the outside, while fat inside (popularly and jokingly known as TOFI). Thus, even a model with BMI in the underweight range had very high level of internal fat, while Japanese sumo wrestlers had normal levels of visceral fat, as well as normal blood pressure and cholesterol levels, despite of their high BMI index measurements. The explanation lies in the amount of exercise they do – so while the sumo wrestlers exercised daily and intensively, the model controlled her low weight by dieting alone, without any exercise.
Crash dieting and yo-yo dieting are to be avoided if we wish to manage our weight well and decrease our levels of internal fat. When we crash diet, we tend to lose fat on the top and bottom parts of the body first, while only small percentage of the internal, abdominal fat is lost. However, when we put the weight back on, which will be very likely as severe dieting would be unsustainable, it would be mainly deposited in the abdominal area. In addition to this, when dieting is severe, the body enters the starvation mode during which some muscle will be lost, but when the weight is put on again, it would be deposited as fat.
Although increased internal body fat is partly genetically predisposed and more common in people with apple shape type bodies, there is something we can do about it. A balanced diet rich in fibre (fruit, vegetables) and carbohydrates high in resistant starches (whole grains, lentil and pulses) is recommended, combined with regular moderate activity and exercise (such as walking and swimming).
Source: Professor Jimmy Bell: Optimal Health: the new paradigm (University of Westminster, Westminster Talks, March 2016)