The words "fit" and "fat" differ by just one letter, but most people see little resemblance between the two. If you're fit, you're obviously not fat, and if you're fat you couldn't possibly be fit.
Or could you? The truth is, being overweight, or even clinically obese, poses no barrier to fitness for most people, according to new research. Exercise apparently bestows its benefits on all, even those who don't inhabit a sleek, athletic body.
A recent study of 3,148 people whose health was monitored for six years found that exercise protected them against high blood pressure, high cholesterol and other risk factors for heart disease.
"Our study shows that as long as individuals maintain their fitness and fatness levels, they are not likely to be at higher risk of developing cardiovascular disease risk factors," lead author Duck-chul Lee said in a statement released when the study was published in the Journal of the American College of Cardiology.
"The finding that improved fitness can reduce some of these risk factors associated with increased fatness may help the two-thirds of the US adult population who are overweight or obese."
Another recent study of 43,265 people published in the European Heart Journal also found that fitness enabled overweight and even obese people to maintain the same risk as normal-weight people of dying from heart disease or cancer - as long as those people maintained their fitness. If they remain fit and metabolically healthy (that means normal blood pressure and cholesterol levels, and no diabetes), their excess weight is a "benign condition", according to the authors of the study.
"We believe that getting more exercise broadly and positively influences major body systems and organs and consequently contributes to make someone metabolically healthier, including obese people," lead author Dr Francisco Ortega said when the study was released in September.
"We measured fitness, which is largely influenced by exercise. Once fitness is accounted for, our study shows for the first time that metabolically healthy but obese individuals have similar prognosis as metabolically healthy normal-weight individuals.''
Of course, excess weight makes a person more likely to develop high blood pressure, high cholesterol levels and insulin resistance - the precursor of diabetes - but exercise helps stave off those problems.
And in a paradoxical finding, people with Type 2 diabetes who are obese actually live longer, according to a recent study in the Journal of the American Medical Association.
Even more surprising, people with heart disease have a lower risk of early death if they're overweight or obese, according to another study in the European Heart Journal.
Those with the lowest risk of death had a body mass index ranging from 26.5 to 35. (A 182cm man who weighs about 105kg has a body mass index of about 30, which is the dividing line between overweight and obese.) So go figure.
The take-away message appears to be that diet and exercise are both important, but diet without exercise is probably a bad idea. And most experts agree that just 30 minutes of vigorous walking five days a week is enough to promote fitness.
So step lively, and live.