“Lose belly fat fast!” “Target belly fat with this one simple exercise!” Social media ads would have us believe we can shrink our bellies with pills and side planks. But is it really as simple as all that?
Why do our bellies get bigger the older we get?
As our bodies age, they get worse at burning fat, so, eventually, even those of us who’ve eaten healthily and exercised all of our lives will find it harder to stay trim. We store fat all over our bodies, some of it just under the skin – subcutaneous fat – and some of it around our organs – visceral fat, which is also known as belly fat.
So in the belly area, we have subcutaneous fat that we can pinch between our fingers and thumbs – the infamous spare tyre. But we also have this much deeper, visceral fat lying beneath our stomach muscles that collects around our organs. We don’t typically notice this until we build up enough for it to start pushing our bellies out but it can be much more detrimental for our health than subcutaneous fat. In older bodies, the visceral fat clings on especially tightly, though sex also plays an important role.
“Even in lean, healthy men and women, men have twice as much visceral fat as women,” says Dr Michael Jensen, an expert in adipose tissue (body fat) at the University of Rochester, Minnesota. “As we go up the obesity scale, men are definitely the kings of visceral fat.”
How is visceral fat different to other fat?
Decades of scientific research suggest that excess visceral fat may be linked to health problems like insulin resistance and diabetes. Insulin resistance is a pre-diabetic state where the body responds less well to the hormone insulin, which helps us maintain normal blood sugar levels.
However, what we’re now realising, Jensen says, is that you’re unlikely to have too much visceral fat unless something has already gone wrong with your other fat stores – in that sense, visceral fat is perhaps more of a ‘canary in the coalmine’ for a dysfunctional metabolism.
Researchers are also now starting to look at differences in gene activity in fat tissues that might explain why some people develop more belly fat than others. Dr Jordana Bell and Colette Christiansen at King’s College London recently published a study using data from twins to home in on epigenetic changes to our DNA – chemical changes to DNA resulting from our lifestyles that don’t affect the code itself.
According to Christiansen, there was evidence that it was epigenetics that was mediating the impact of diet on visceral fat. In other words, what you eat could turn up the dial on those genes particularly associated with piling on the pounds around your waist.
What makes it so tough to shift?
It’s not entirely clear. “There is some thought that visceral fat cells are more hearty – they live longer than subcutaneous fat cells,” says Jensen. Recent research at the University of Sydney suggests there may be a ‘preservation signal’ unique to visceral fat cells that is triggered by repeated attempts to fast, meaning that on some diets, trying to lose weight only encourages your belly to hold on to its fat for dear life.
There’s also evidence from studies in mice suggesting that immune cells in fat tissue may be partly to blame for belly fat and some of the health issues associated with it. If the same occurs in humans, then as we get older, these immune cells get old too, and cantankerous; they accumulate specifically in visceral fat, sending out signals that trigger inflammation and generally misbehave in ways that interfere with our metabolism.
So what should we do about it?
It’s not that easy to single out visceral fat with a diet and exercise plan. Your best bet, says Jensen, is to go for fat loss in general – anything that creates a ‘negative energy balance’ should blast the belly fat along with the rest of it. Other researchers suggest there are tactics you can employ to target visceral fat specifically.
US researchers at Ketchum University, for example, reckon that spreading out your fat intake across several small meals during the day should help. They argue that when you eat a big meal, fat transporter molecules called chylomicrons get stuck in an area close to the gut and are then digested and stored in the closest fat deposit – the belly. Interestingly, men tend to produce more and bigger chylomicrons, which they suggest may go some way to explaining why they accumulate more belly fat.
And what about drugs? Well, there is already one known drug, called pioglitazone, that seems to work indirectly on visceral fat, leading to fat being diverted from visceral to subcutaneous stores, but it’s only approved for people with diabetes.
As part of Christiansen’s research, she hopes it might be possible to track down genes that could become new targets for big pharma companies, in order to help to people to gain control of belly fat before it becomes a risk to their health.
“Could we target visceral fat or could we target in pre-diabetes before people are actually diabetic, or before they are insulin resistant?” she says. “Are there things we could do to reverse that so they go back to a normal metabolic state?”
The bottom line is that there’s no magic solution for banishing belly fat, whatever the ads might say. So, until science reveals more about what causes it, all we can really do is double down on the diet and exercise, or accept our jiggly bits as we move into middle-age.
Read more about diet:
- The artificial meat factory – the science of your synthetic supper
- Why is cheese so addictive?
- Is there a physical limit to how much food you can eat in one sitting?