The Daily Telegraph - Features
How navel gazing can extend your life – the truth about belly fat
Although many of us consider all body fat as bad, it is not. Aside from providing energy and keeping you warm, it is vital for building cell membranes, synthesising key hormones and absorbing certain nutrients. Fat storage was key to our survival as a species.
But not all fat in your body is equal, and where the fat is deposited is an important determinant of health. Belly fat is a good example of this.
Most of us consider fat around the middle to be the same as fat under our skin, on our hips or elsewhere. The latest science, however, underlines how different it is: belly fat is, in fact, a glimpse into our future and longevity.
In general, and particularly in females who have more of it, fat stored around the buttocks and thighs is much healthier and protects against heart and metabolic disease.
In contrast, belly fat, which is often nestled around your liver and intestines – is metabolically much more active, closely linked to your blood levels and behaves very differently from the fat in other parts of your body.
More accurately called visceral fat, belly fat increases the risk of many conditions, particularly Type 2 diabetes and heart disease. It does this by interfering with how your body responds to glucose and insulin.
Males have more of this central fat on average than females. In evolutionary terms, this may be related to their duties of walking long distances and fighting, as belly fat can be converted into energy in an emergency more quickly than fat elsewhere.
Whatever the reason, males’ propensity to lay down visceral fat is one of the reasons we are more at risk of heart disease during midlife than women. This is despite the fact that women, overall, have a higher percentage of body fat.
In contrast, females tend only to lay down fat around their abdominal organs once the healthy stores in their buttocks and thighs are full. Similarly, once abdominal stores reach maximum capacity, fat starts overflowing into organs such as the liver, heart and pancreas, and even muscles, where it can interrupt their normal functioning.
Understanding how much visceral fat you have isn’t just a case of looking in the mirror. To assess it properly, we need to use DEXA – or bone density – scans, first used to detect weak bones associated with osteoporosis. I have been measuring twins for more than 30 years and these DEXA scans have taught us that, often, visceral fat is invisible from the outside.
For example, some men who look relatively slim still have significant amounts of visceral fat inside. This has earned them the nickname of TOFIs, an abbreviation for “thin on the outside, fat on the inside”.
As we age, we are more likely to accumulate visceral fat. My own levels, like my belt size, steadily increased without me noticing, until I started taking my health seriously around 12 years ago.
Since then, I’ve reduced my visceral fat levels (and belt size) through dietary changes, and no doubt added more healthy years to my life.
Visceral fat increases the risk of conditions such as Type 2 diabetes and heart disease
There is plenty of research from ZOE, and other groups, that lower levels of visceral fat are predictive of good long-term health. This month, ZOE published a clinical trial in Nature Medicine which found that, compared with people who followed standard dietary advice based on lowering fat content and limiting calories, those who followed ZOE’s advice significantly reduced their waist circumference – a marker of reduced visceral fat. This was a bigger effect than overall weight or general measures of obesity such as body mass index, or BMI.
This is a good sign that you can reduce belly fat by enhancing the quality of your diet and making smarter food choices based on your individual gut health, blood sugar and blood fat responses.