Toxic waist: meet the underbellyIt’s the silent killer, the danger that lurks within. Time to meet the fat killing you from the inside By Peta Bee A middle-age (or any-age, for that matter) spread not only looks unattractive - it's also bad for you: an increasing amount of evidence shows that midriff fat puts people at a much greater risk of serious health problems. But it’s not just the fat you can see that concerns experts. Invisible, internal "visceral" fat - the type that sits around the major organs - is more of a worry than the spare tyre as it has been linked to a range of health problems. Located deep within the body around the stomach, visceral fat, or belly fat, fills spaces between internal organs. It’s different from subcutaneous fat, the kind that lies directly underneath the skin and the stuff you can pinch between your fingers. And while too much of this visible flab is never good news, too much visceral or "inside” belly fat is described by some experts as dangerously toxic. But why? All types of body fat are more than just slabs of lard. Fat is like another organ – it has blood vessels and releases hormones and proteins that affect your metabolism and can impact on everything from your fertility, mood, immune system and ability to think clearly. Internal visceral fat appears to secrete more chemicals. It is known to cause inflammation to the colon and artery walls, raising the risk of heart disease, high blood pressure and some types of cancer. It also seems to affect glucose levels, possibly triggering type 2 diabetes. Some research even suggests visceral fat affects mood by increasing production of the stress hormone, cortisol, and reducing levels of feel-good endorphins. It is clearly dangerous, but how do we know we have got it?
The warning signs
Finding out whether your visceral fat levels are too high isn’t easy. A specific MRI scan is the only certain way. It’s true that the bigger your waistband, the more likely you are to have higher levels of internal fat too. One recent study from the American Cancer Society, which tracked the health of more than 100,000 people over nine years, found having a large waist size doubled the risk of dying from any cause during the study period compared to those with smaller waists.
Another report in the Journal of the American College Of Cardiology a few years ago published the results of a study of 3,000 people that suggested that carrying even a small "pot belly" means a high risk of heart problems, even when body weight is in the normal range. The research showed that just three or four inches around the abdomen is the external sign of a build-up of fat in the arteries, and that those with the biggest waist measurements were twice as likely to have calcium deposits, which form the plaque that hardens the arteries and increases the risk of heart attacks.
But it’s not always the case. Relatively thin people can have high levels of belly fat lurking beneath the surface. So how can you tell? Some body-fat monitors (used by gyms) may be able to give you an idea, and if you look thin, but have a higher than expected fat reading, that could be a clue. Otherwise it’s a case of keeping tabs not just on your waist, but on the size of your waistband.
THE D.I.Y FAT TESTThere are home-checks you can carry out to find out if you are in the danger zone. Place a tape measure around your middle, over your belly button. A measurement of more than over 94cm (37in) for men means you are at increased risk of heart disease and diabetes. Over 102cm (40in) for men puts you at the highest risk of these conditions. Having a narrower waist doesn't mean you're in the clear. Check your waist to hip ratio (WHR) to determine whether your fat is distributed unhealthily. If you have a visible waist, measure around the narrowest part; this is your waist circumference. Next, measure around your hips, just below the point where the top of the thigh bone meets the pelvis. Divide your waist measurement by your hip measurement to get your WHR. If your WHR is higher than 0.9, you are an unhealthy, apple-shaped man and are more likely to have high levels of visceral fat too.
Can running help?
In general, researchers seem to think a combination of aerobic exercise, including running and cycling, and resistance training is the best way to prevent belly fat from forming. “Weights can be helpful,” says Louise Sutton, head of the Carnegie Centre for Sports Performance at Leeds Metropolitan University, “But any form of resistance work can help, including exercises on a vibration platform at the gym.” Over a six month period, overweight subjects in one European study used a Powerplate device regularly as part of a fitness programme and lost more weight and significantly more visceral fat than a group following a conventional diet and exercise plan.
However, emerging evidence suggests that aerobic exercise may play a particularly key role. Last year, Dr Cris Slentz, an exercise physiologist at Duke University in America, compared the effects of 12 miles’ jogging on a treadmill at 80 per cent of maximum effort every week with three weekly sessions of 3 sets of 8-12 reps on weights machines. A third group did a combination of the two types of exercise. What Slentz discovered was that the runners had the most visceral fat reduction. While the combination group had more total fat reduction, their loss of visceral fat was less than the runners’ group. And the weight trainers lost some subcutaneous fat but actually gained a bit of visceral fat. “If you want to lose belly fat, visceral fat and liver fat, vigorous aerobic exercise works better,” Dr Slentz said.
Another recent study suggested that running - or at least ultra-running - might have specific visceral fat-burning benefits. In findings presented at the Radiological Society of North America conference in Chicago a couple of years ago, German researchers reported how they followed a group of 44 runners during the 4,488-kilometre TransEurope Footrace from southern Italy to Norway, collecting medical data from them on a daily basis. They found that not only did the runners lose almost half their body fat from start to finish, but that initially it was the visceral fat that disappeared fastest. Overall, the runners lost 70 percent of their visceral fat. What is it about running that might be so helpful? Undoubtedly, intesntiy is important - numerous studies have linked interval training to lower levels of visceral fat. But Dr Slentz says it simply burns more calories than resistance training does. "I really believe that's all there is to it."
What foods should you eat (and avoid)?Scientsts are just beginning to understand the way diet can help to control levels of visceral fat. What they now know is that people who consume at least three daily servings of whole grains a day have levels of visceral fat around 10 per cent lower than those who eat more refined grains like white flour, white pasta and white rice. “The soluble fibre found in beans, vegetables and fruit is also important,” says Jennifer Low of the British Dietetic Association. “Good sources are apples, beans and lentils, oats and pulses.” One serving would be 2 apples or a small bowl of porridge.
Indeed, a study in the American Journal of Clinical Nutrition showed that a calorie-controlled diet rich in whole grains trimmed extra fat from the waistline of obese subjects. Subjects who ate all whole grains (in addition to five servings of fruits and vegetables, three servings of low-fat dairy, and two servings of lean meat, fish, or poultry) lost more weight from the abdominal area than another group that ate the same diet, but with all refined and highly processed grains. "Eating a diet rich in whole grains while reducing refined carbohydrates changes the glucose and insulin response and makes it easier to mobilize fat stores," says researcher Penny Kris-Etherton, a professor of nutritional sciences at Penn State University. “Visceral fat is more metabolically active and easier to lose than subcutaneous fat,” Kris-Etherton says. “Especially if you have plenty of it and the right conditions are met, such as the ones in our study."
What about ‘good’ body fat?
Most of us know about good and bad cholesterol, but did you know there is good and bad body fat and that the right kind of fat can actually make you thin? Several new studies have found that adults can have high levels of calorie-burning brown fat that could help them to lose weight rather than gain it. It has long been known that babies have deposits of brown - or ‘good’ - fat around their shoulder blades to help maintain the body’s core temperature after birth. But until recently they thought it disappeared in infancy when its physiological importance had been exhausted.
Now, it has been shown that brown fat not only persists into adulthood, but that it could help people to lose weight and keep it off. Three separate studies published in the New England Journal of Medicine (NEJM) also suggested that boosting brown fat stores helped the body to burn off ‘bad’ fat - the more familiar ‘white’ fat that stores up calories and settles stubbornly on the waistline and thighs. Brown fat is also thought to play a role in diseases like diabetes that are linked to obesity and energy balance. So how does it work? Brown fat, which is also found in small mammals like rats and mice, becomes activated naturally only when people are cold and on the verge of shivering. Chilly temperatures simulate the conditions that lead to the evolution of brown fat - namely, life threatening cold in babies that do not possess the means to keep themselves warm. Scientists are now investigating whether is it possible to reproduce the body’s internal calorie burning furnace in a test-tube. But could there be a simpler solution? According to Professor Mike Cawthorne, director of metabolic research at the University of Buckingham who has researched the effects of brown fat, says warmer temperatures, abundant food and too little activity have effectively ‘switched off’ brown fat’s usefulness in the modern world. “Even 30 years ago it was more difficult to stay warm than it is now,” he says. “Today, our homes, cars, offices and shops and almost everywhere we go is warm.” Just turning off the central heating or going running in the cold could help spur brown fat into action. “If we were to expose ourselves to cooler temperatures more often, then a lot of people would probably lose weight,” he says. “Either that or plunge into icy water or a very cold shower. We need to activate brown fat and there are simple ways to do it.”