Can you be fat and fit ? | The Body of Evidence

Can you be fat and fit ?

Can you be fat and fit? I tackle the question in my latest article for the Montreal Gazette.


A question that often comes up is whether you can be both fat and fit. The short answer to that question is yes. You can be both fat and fit in the same way that you can be both blond and left handed. Fatness and fitness denote two separate things.

Being fat, or, more scientifically, being obese, refers to having excess visceral fat coating your internal organs. It is widely felt that visceral fat is more dangerous than the subcutaneous fat that is stored in a layer under your skin.

Fitness refers to the efficiency with which your muscles and the rest of your body produce and use energy. A fit person can exercise harder and longer without accumulating lactate in their muscles. It is the accumulation of lactate that leads to muscle fatigue and soreness.

Thus fatness and fitness are two different concepts, and you can certainly be fat while still being fit. However, it would be wrong to say that the two concepts are completely unrelated and that obesity is completely benign.

The idea of metabolically healthy obesity has been debated for the past decade. Obesity increases the risk of diseases like high blood pressure, diabetes and high cholesterol. However, some obese individuals do not have any of these issues. Thus the question becomes: If you are obese but free from disease, is your risk higher than that of a non-obese individual who is also free of disease?

In a recent study in England, researchers examined electronic health records of 3.5 million people and categorized them according to their body mass index. They also then categorized them according to whether or not they had diabetes, high blood pressure or high cholesterol. Thus, they were able to compare obese and non-obese patients who were "metabolically healthy," that is, free of these three risk factors. About 15 per cent of the population was categorized as being obese and metabolically healthy.

Over the course of five years, obese individuals with none of the three risk factors were 49 per cent more likely to develop heart disease, 7 per cent more likely to have a stroke, and 96 per cent more likely to develop heart failure. In absolute terms the increase in heart disease was about 1 extra case per 1,000 individuals, which seems small but is important when you consider the population-wide implications.

However, it is also important to note that the standard risk factors (diabetes, hypertension and cholesterol) carried a much heavier disease burden. Having one, two, or all three of those diseases increased the number of cardiac events by five cases per thousand, seven cases per thousand, and 10 cases per thousand. Of course, we must also remember that obesity itself increases your risk of developing these risk factors, and the metabolically healthy person today may very well become the diabetic of tomorrow. If this study had more than five years' follow-up, that likely would have been seen.

What this study and prior research, show us is that obesity even on its own carries a certain cardiovascular risk, but less than diabetes, high blood pressure and cholesterol.

Some have suggested that we should shift our focus away from weight loss as a public health goal. There is some merit to this argument, and it would be wrong to focus solely on a patient's weight as a marker of heart disease, especially as the traditional cardiac risk factors are more important and, frankly, easier to treat. But it would be equally wrong to suggest that obesity is a benign condition.

There has been a recent tendency to dismiss the rising prevalence of obesity in our society. But when you consider the soaring rates of childhood obesity, and that we are seeing Type 2 diabetes in children, if we do not face this problem now, we will be facing a potentially serious public health problem down the road.