Are you slim? Do people envy your ability to stay slender while they struggle to keep the pounds off?
That's great but don't be looking too smug yet.
Sounds impossible, but the person who is visibly fatter might be fitter.
Studies done in Britain since 1994 by Professor Jimmy Bell of Imperial College London show that fat is not just a problem for the heavy-set.
What Prof Bell has found is that it isn't so much about how much fat you have, but where in the body it is stored.
Sumo wrestlers probably have a better metabolic profile than someone slimmer because their fat is primarily stored under the skin rather than throughout their vital organs and muscles.
This kind of hidden fat is called "visceral fat" and coats the vital organs like the heart, liver and pancreas. It is then metabolised by the liver into cholesterol - good and bad - that circulates in the blood.
"Bad" cholesterol, also known as low-density lipoproteins, collects in the arteries where it will form plaque that narrows the blood vessels.
The studies have found that, unlike its indolent sounding name, fat is actually pretty active. Fat cells send out hormones that affect a person's mood and fertility levels.
These cells also send out chemical signals that transform the body into targets for heart disease, diabetes and high blood pressure.
The signals can send fat to be stored in organs and under-used muscles.
So you can be skinny but still be at as much as risk as someone who appears obese.
Prof Bell - who coined the term tofi (thin outside, fat inside) - has been using MRI scans to find that in some cases, a thin person could be carrying twice the amount of fat of someone outwardly larger.
One study found that an outwardly healthy man aged 34, at1.8m tall and weighing 80kg, had 4 litres of visceral fat in him when he should just be carrying just 1litre.
The Body Mass Index (BMI) test, generally used to measure if someone is obese or otherwise, cannot highlight hidden fat.
The amount of hidden fat you carry can be pinned down to genes or environment. If you have a sedentary lifestyle, spend long hours at your desk, don't exercise and eat sugary and fatty foods, you could be at risk.
Genetically, those who are apple-shaped - more fat in the abdomen - are more at risk than one who is pear-shaped, where fat deposits in the hips, thighs and backside.
Professor Bell even states that solving the problem isn't just down to dieting. Even professional models have been found to be tofi.
Only regular exercise will help burn away the hidden fat. A consultation with your doctor will help focus on what kind of exercise would be best.
Bell told the BBC: "When you diet, you don't lose the right type of fat. If you exercise, you lose more of the bad fat."
This article was first published in The New Paper.