Can you carry extra weight and still be healthy? In other words, fat but fit? A major new study from Denmark says yes, and it is shaking up everything we thought we knew about weight, fitness, and health.

The research followed over 85,000 adults for five years. It found something surprising: people with higher BMI weren’t always less healthy. In fact, some overweight and moderately obese people had no higher risk of death than those in the so-called “healthy” weight range.

The study, presented at the European Association for the Study of Diabetes, looked at how BMI relates to mortality. The results formed a U-shaped curve. That means the people at the very low and very high ends of the BMI scale had the highest risk of death. However, the individuals in the middle, even those technically considered “overweight,” fared better than expected.

“Healthy Weight” Isn’t Always Healthy

People who were underweight had the highest risk of all. Those with a BMI below 18.5 were almost three times more likely to die than people with a BMI between 22.5 and 24.9. That group, the top end of the “healthy” range, had the lowest risk overall.

Master / Pexels / Per the study, a BMI of 18.5 to 20 had double the death risk compared to the higher range. Even those between 20 and 22.4 had a 27% higher risk.

So much for “thinner is better!”

People who were overweight (BMI 25–30) and even mildly obese (BMI 30–35) didn’t show a significant increase in death risk. That flips the usual story we hear. According to this data, carrying extra weight isn’t always the threat it is made out to be, especially if you are otherwise healthy.

However, the risks climb again with severe obesity. Once the BMI reaches 40 and above, the danger increases more than twice. This is the point where extra weight starts to seriously strain the body.

BMI Isn’t the Health Score You Think It Is

So, why are people with lower BMIs sometimes at greater risk? One possible reason is reverse causation. That means some people might have had low BMI not because they were healthy, but because they were already sick, and the illness caused them to lose weight.

Another explanation is that fat can act as a buffer. During serious illness or treatments like chemo, having some fat reserves gives the body something to work with. Someone with very little fat may not have the energy reserves to recover.

Remember, fat distribution plays a huge role. Fat stored deep in your belly, around your organs, called visceral fat, is far more dangerous than fat on your hips or thighs. Visceral fat is linked to heart disease, type 2 diabetes, and even brain decline.

That is why someone with an apple-shaped body can be at greater risk than a pear-shaped one, even if their BMIs match.

Alex / Unsplash / Yes, being “fat but fit” is real for some. You can be overweight and still be metabolically healthy if you are active, eat well, and have good markers like blood pressure, cholesterol, and blood sugar.

Fitness Beats Thinness Every Time

Several large studies have found that being fit is a stronger predictor of longevity than body weight. Fit people, even if they are overweight, often live longer than thin people who don’t exercise. Being unfit is the real danger, regardless of your weight.

However, that doesn’t mean weight doesn’t matter. Obesity is still linked to plenty of issues like joint pain, limited mobility, and certain cancers. And while exercise helps, poor diet is still the main driver of obesity. You can’t outrun your fork.

So, don’t obsess over the scale. BMI isn’t the whole story. Focus on how you feel, how you move, and what your body can do. Eat a solid diet. Get your heart rate up regularly. Sleep well, and most importantly, check your bloodwork.