Did you know that some body fat is worse than others? When I was a trainee surgeon, the fat that was on the inside, snuggled around the organs, was a glistening yellow, with a healthy blood supply. But these internal fat deposits are now accused of being health hazards. Like all sinister things, they go under various names – visceral, intraperitoneal, active or belly fat. And we’re not talking about “love handles” of subcutaneous fat beneath our skin. Visceral fat is linked to a higher risk of insulin resistance and diabetes. These, in turn, increase the risk of strokes, heart disease and some cancers.
The solution
It is not completely understood how visceral fat makes the body resistant to insulin (and hence allows blood glucose levels to rise). One theory is that the liver and muscles become less sensitive to insulin when there are higher circulating levels of fatty acids, which occurs when you have a deposit of fat inside. Fredrik Karpe, professor of metabolic medicine at the Oxford Centre for Diabetes, Endocrinology and Metabolism, explains: “The turnover of visceral fat is more dynamic; if you don’t eat, then it reduces much more quickly than other fat depots. But visceral fat does something nasty.” Hip and leg fat accumulates slowly and is released slowly. But Karpe points out that, in terms of its evolutionary role, visceral fat generates a massive supply of energy from fatty acids when it is desperately needed. But, with our more sedentary lives and increased food intake, it now leaks fatty acids, whether we need them for energy or not.
If we are apple- or pear-shaped may depend on how our genes are expressed rather than any one gene defect. Karpe warns that, as well as diabetes, belly fat can cause sleep disorders, as it’s the equivalent of sleeping with a football inside your abdomen. This pushes your lungs up and can disrupt sleep.
The good news is visceral fat is so dynamic that you can shift it. You just have to eat less and exercise more – about half an hour a day of quite vigorous exercise should do it. If you can’t exercise without eating more, then just eat less: you need to have a negative energy balance for your belly to melt away. This is obviously not easy. But there is a handy way to see if you have a problem: measure your waist and then your hips (around the largest point) and divide the waist by the hip. If the resulting number is more than one for men or 0.85 for women, then you may have too much. You are excused from sit-ups – all they will do is help your abdominal muscles keep the fat in – but you should strive to shed it in other ways. Karpe is very clear: “It’s unwanted and you can’t have too little of it.”
