Whether we like it or not, fat loss appears to be more of a focus than ever thanks to the rise in use of weight loss jabs. But putting aesthetics to one side, what are the health implications of storing fat in certain areas of the body – and what are the best, safe strategies for fat loss if you don’t want to resort to Ozempic?
There are two key types of fat in our bodies, explains geneticist Giles Yeo, a professor of molecular neuroendocrinology at the University of Cambridge. “Subcutaneous fat lives under the skin largely and has a tendency to accumulate around the hips, bum, thighs and underarms. It’s considered the ‘healthier fat,’” he says.
Adam Collins, associate professor of nutrition at the University of Surrey, agrees subcutaneous “is not an issue – particularly if you store it in the periphery (arms legs, hips, buttocks and thighs),”. He adds that women “tend to have a better turnover of that fat than men and are better fat users in general.”
Then there’s visceral or ectopic fat “which tends to live around the organs,” Yeo explains. “We all have some level of visceral fat, but if you have a lot of it, this could look like a beer belly, for example. You see very typical middle-age men who have otherwise relatively skinny arms and legs, but a really tight beer belly – that’s what we consider visceral fat and it’s associated with a number of metabolic conditions and diseases.”
These include insulin resistance, hypertension, high cholesterol, and an elevated risk of developing type 2 diabetes and heart disease. Recent research has also suggested a link between having more visceral fat during midlife and a higher risk of developing dementia.
If your fat wobbles, it’s less of a worry
Men tend to accumulate more visceral fat than women, Yeo says, though this can change after menopause when hormonal changes mean they tend to store more fat around the abdomen.
You may assume that if someone’s carrying more visible fat, they’re going to have more visceral fat, but it’s not a guarantee, Collins adds. “Some people have a lot of body fat, but very little visceral fat – a sumo wrestler is the classic example of this.
“More worryingly, some people have very little body fat, but lots of visceral fat.” This is why it’s also referred to as “hidden fat.” It is possible to be carrying excessive amounts of both types of fat, though.
How to spot the difference between subcutaneous fat and visceral fat? Ask simply: does it wobble?, says Yeo. “You can store fat around the tummy that is not visceral fat, but it’s usually wobbly. If it’s wobbly rather than tight, that’s the key difference. If it’s extra wobbly, then it’s going to be underneath the skin, whereas the fat that sits right next to the organs is tightly packed, so your belly tends to be tighter.” The other way to look at it is, if you have skinny arms and legs but still have a bigger belly, then you may be carrying more visceral fat than is healthy, he adds.
Ignore body fat percentages and instead, keep an eye on your waist and neck
When it comes to the health implications of excess body fat, as it’s where the fat is located that’s most important, Collins says body fat percentages or BMI calculations may not be particularly helpful in painting the full picture. “Waist circumference is a better predictor of how much visceral fat you may be carrying,” he says. The NHS offers an online guide that helps you calculate your waist-to-height ratio to help to give an indication of this. In general, it recommends aiming to keep your waist size to less than half your height.
Naveed Sattar, professor of cardiometabolic medicine at University of Glasgow, says each of us has a weight threshold (dependent on things like age, sex, ethnicity and genetics), “which when reached leads to so called ectopic fat – which spills into metabolically important organs – such as the liver, pancreas and muscle, as well as leading to more fat around blood vessels, in and around the heart and kidneys.” This is a driver of type 2 diabetes, heart attacks and strokes.
Meanwhile, excess fat in the neck can contribute to sleep apnoea via a physical effect, he adds. “More fat in the neck and around the epiglottis can contribute to sleep apnoea through a mechanical effect – including fatty tongues which are more liable to collapse and block the airway when folk lie down to sleep. Weight loss improves this.”
The good news: hidden fat is the first to go when you exercise
“You have no control about where you carry fat in the body and hence you have zero control over where you lose fat,” Yeo says. “Fat comes off where we are genetically predisposed to lose it.” But the good news from a health perspective is that visceral fat “is the most easily accessible fat to your body,” he says, meaning it’s likely the first to go when you exercise.
Put simply, fat loss is about maintaining a calorie deficit, “eating less and moving more so that you increase your daily energy expenditure,” he explains. Exercise “helps by increasing your muscle mass and therefore your metabolic rate, or metabolism, which will eventually encourage more fat loss over time.”
Will eating more protein help with fat loss? “Protein itself does not burn fat, but eating more protein will help you to feel fuller, meaning you may eat less in general because it’s more satiating,” Yeo says.
So what’s more important, diet or exercise? Both. “Yes, moderate activity burns fat, but activity alone is a hard way to lose weight, though it does lead to lower fat and higher muscle mass,” says Sateer. “For most people, it’s about dietary changes to cut weight sustainably, which then lowers ectopic fat in the liver, for example, so that your risks for metabolic disease decline.”
Try fasting or carb cycling – and get a good night’s sleep
Merav Mor, a physiologist and co-founder at handheld metabolic tracker Lumen, recommends ‘carb cycling’ – alternating between low- and high-carb days to allow the body to efficiently switch between using fats and carbs for fuel when required, or intermittent fasting where you don’t eat for a window of time. Any exercise improves mitochondrial function, which makes you more efficient at burning energy – so try brisk walking, cycling or swimming along with strength training to create stronger muscles and bones and increase lean body mass.
Sleep has a significant impact on our hunger hormones – we often crave sugary or fatty snacks when we’re sleep deprived. Getting consistent, quality sleep promotes hormone regulation, insulin sensitivity, circadian rhythm alignment and reduces inflammation.