A ripple of flesh beneath the skin could well be a sign of ‘lucky fat’, according to a new study. Researchers at the University of Brunel have found that the subcutaneous kind of fat beneath the skin (the ‘wobbly’ stuff like double chins), as opposed to that around the organs, has no bearing on a number of diseases thought to be linked to obesity. 

In the study of 37 conditions, a causal link between those with a Body Mass Index (BMI) above 30 was found in 21. Of that number, 12 ailments, such as type 2 diabetes, stroke and coronary artery disease, only afflicted those without ‘lucky fat’, according to data collected from 500,000 people. The other nine conditions – among them arthritic knees, and deep vein thrombosis – found that the presence of additional fat, no matter where it was placed, was enough to trigger a condition. 

This research is welcome news, says Dr Giles Yeo, principal research associate at Cambridge University’s Metabolic Diseases Unit and author of Gene Eating, because “not all fat is the same.” The obesity rate in Britain stands at 28 per cent (a further 36 per cent are overweight), with BMI at which a rank of 30 or above is classified as obese, being the most widespread measure of the condition. But BMI is “not hugely useful” in determining what kind of fat you may have, he points out, as even a high reading “is not going to tell you your body shape, and your body shape – where you store your fat – is very important in how ill or not ill you become.” Here’s what you need to know about the new study: 

How do I know if I have ‘lucky fat’? 

“Unfortunately it is impossible for people to know without using a method like magnetic resonance imaging (MRI) to look inside the body,” says Dr Hanieh Yaghootkar, a lecturer in biosciences, who led Brunel’s research. “Surprisingly, people with the same waist circumference can have very different amounts of visceral fat inside their bodies.” A beer belly, which is typically rigid, is of greater concern than “the stuff you store on your backside,” he explains, as that visceral fat “gives off different hormones, different signals.” Excess visceral fat “gives you a large amount of problems, and men tend to have that fat, which is why men have higher cases of heart disease.”

Does ‘lucky fat’ make me more likely to avoid disease? 

Lucky fat is only “partially lucky,” warns Dr Tim Frayling, the Brunel study’s co-author. “The extra weight itself – even though it’s not putting up your blood pressure – will still damage your knees, hips and joints, and increase your risk of osteoarthritis, rheumatoid arthritis and deep vein thrombosis.” 

Which genes are at play? 

Yaghootkar says the team “are still working on identifying the causal genes but one of the highly likely candidates is PPARG”, which has been implicated in the pathology of diseases including obesity, diabetes and cancer. “I don’t think the exact genes actually really matter,” Yeo adds, saying that looking at our parents’ waistlines is also an important indicator of what’s to come for our own. 

To date, 400 genes have been identified as having the potential to affect our weight. The FTO gene, for instance, makes carriers 30 per cent more likely to be overweight; MC4R, meanwhile, is a receptor that impacts our metabolism, controlling how much energy from the food we consume is used, and thus how hungry we feel. Current estimates place the potential impact of our biological makeup on our waistline as high as 70 per cent. 

If I don’t have ‘lucky fat’, what can I do? 

Lowering weight – whether it’s ‘favourable’ or otherwise – is the key way to reduce the risk of obesity-induced diseases, the researchers say. “There is no one-size-fits-all treatment for obesity and people respond differently to different interventions,” adds Yaghootkar, who advises that people “consult with their GP or healthcare providers.” Regardless of whether someone has “favourable or unfavourable adiposity, living with obesity could still increase a person’s risk of certain health conditions, and those with a favourable adiposity are still at a higher risk of conditions such as gallstones, osteoarthritis, thromboembolism and psoriasis as a result of mechanical effect of excess weight.” 

The NHS says obesity reduces life expectancy by an average of 3-10 years, depending on the severity. It has also been found to cause bowel, breast and womb cancer, liver and kidney disease, reduced fertility, and pregnancy complications. 

There is a “substantial biological and genetic component” to weight loss as well as gain, Frayling says, “as two people who lose the same [amount] may be at very different risks.” Logic previously dictated that apple-shaped types with more fat around their middle were more likely to suffer from metabolic conditions than their pear-shaped counterparts, but this may be too blunt a tool, he adds.