If you can't see your toes because your tummy is in the way, there is little doubt that it is harming your health. But it may not always be this obvious that your girth is creeping out of control. For a more scientific approach, 35 inches is the “magic” or “tragic” number when it comes to the size of our waists, according to scientists from Tufts University in Boston. Risks to our health climb once women's waists creep above 35in (89cm) and men's edge above 37in (94cm), and over 40in (102cm) we should have serious concerns. To find out how to measure your waist, see the panel on the facing page.

While the 35in and 37in rule works for the average person, if you are short or tall, from certain ethnic groups, or are dealing with a child's size, it is better to look at your waist-to- height ratio. Put simply, your waist should be less than half your height.

The idea that tummy fat is more dangerous to our hearts than that deposited on other parts of our bodies has been emerging for a while, but research appears to give extra credence to the importance of keeping our waistbands as trim as possible, even if you are an otherwise normal weight. The problem lies in the fact that having a proportionally large middle means that you are likely to be carrying deep “visceral” fat that pads itself around internal organs such as the heart and liver. This, in turn, seems to increase the manufacture of harmful blood fats and cholesterol. It also interferes with the delicate balance of insulin production that controls sugar levels in our blood and the risk of developing diabetes. One recent piece of research has even suggested a relationship with larger waist size in middle age to an increased risk of dementia and Alzheimer's in later life.

The good news is that shedding weight can significantly shrink the dangerous fat buried deep inside. Using special imaging techniques, doctors have found that when obese patients burn off an average of 20 per cent of their body weight, the layer of blubber clinging to the heart can be shrunk by an average of 32 per cent. This means it really is worth getting going on a general weight-loss regimen, not just for aesthetic reasons, but because it can improve your chances of survival. And given that the loss of deep fat can be proportionally higher than overall weight loss, every little bit helps.

Keeping an eye on carbs

While any general loss of weight is beneficial, it seems that there are some things you can do from a dietary perspective that may give you a helping hand in the battle of the belly fat. For example, turning to low glycaemic carbohydrates (such as wholemeal bread and brown rice), which are more slowly digested, in place of high GI refined carbs (such as cakes and biscuits) is one such tack. While the latter are absorbed into your system rapidly after eating and raise sugar levels in your blood quickly, unrefined ones tend to have the opposite effect.

In one large study conducted by scientists at Tufts University, it was discovered that people tucking in to fibre-rich carbohydrates, which are the generally accepted “good guys” of the carb world, such as wholegrain breakfast cereals, brown pasta and rice, wholemeal bread, pitta and tortilla wraps and plenty of fruit and vegetables, had much smaller increases in waist sizes than those wolfing down high GI refined versions. Women who ate the most fibre-packed carbohydrates in their diets were found to reduce their body mass index.

Choosing low-fat dairy foods

A diet containing good amounts of dairy foods, particularly low-fat ones such as skimmed milk, has also been linked with lower risk of accumulating fat around the waist. For instance, research published in the Public Health Nutrition journal looked at various aspects of the diets and lifestyles of a group of women and analysed their body measurements. The results showed that a good intake of low-fat dairy foods was the main dietary factor associated with less fat being stored around the middle of their bodies. Whether this tummy-shrinking effect was because of the large intakes of calcium from these dairy foods (scientists think that the calcium may help fat cells to release some of their fat) is not yet clear.

The beer-belly conundrum

Does a man's belly expand when he is partial to a few pints simply because of the calories it provides or another mechanism? There is no solid research to tell us the answer either way, although a study of Czech men (published in the European Journal of Clinical Nutrition in 2003), who are generally considered to be high beer consumers, revealed no significant relationship between pints glugged down and tummy size. That said, while beer and lager have 200 calories a pint, a double shot of spirits with a diet mixer has 100. Swapping from beer to shorts would, unit for unit, help general weight loss.

Can supplements help?

Some supplements may help to banish your gut. Norwegian scientists from the Link Medical Research Centre found that overweight and moderately obese people who took with 3.4g of conjugated linoleic acid (CLA) daily for six months showed significant loss about the tummy and legs. While CLA occurs naturally in meat and full-fat dairy foods, you need to supplement to get this kind of intake and, of course, that is not enough for your tummy to melt away. A healthy diet is also called for and, not surprisingly, exercise speeds up the whole process.

Exercise and a healthy diet

When it comes to exercise the key is not doing hundreds of sit-ups in a vain attempt to “spot reduce” your belly. They will strengthen your lower back and tummy muscles, but will not burn fat, which is what is needed to reduce the paunch. You need exercise that raises your heart rate to do this, such as fast walking, cycling or jogging. Thirty to forty minutes a day is ideal but anything is better than nothing and you can build up from 10 to 20 minutes and then 30 and 40 minutes over time.

Combine this with a healthy eating plan, which includes wholegrain and low-fat dairy foods, such as skimmed milk, plenty of fruit and vegetables and lean meat, fish, eggs and pulses.Give yourself three months and your toes should be coming back into view.

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