Is it better to be fit or thin? It seems every few months there is something on the topic. If you ask Google this question, you’ll get thousands of articles, blogs and commentaries.

Personally, I can’t stand the question (yes, I notice the hypocrisy in using it as my title but I needed something). I’ve never seen anyone ask if it is better to have low blood pressure or not smoke, or have diabetes or high cholesterol? So why do we ask this particular question and why is there so much research comparing the two? It assumes that we all have a choice to be either one, both or none. All we need to do is just flip some sort of switch.

A lot of the hype comes down to an ill-conceived notion that if we’re fat or unfit, it’s because we have decided to be that way and if we want to, we can easily change that. This is total nonsense. As anyone who is unhappy with their weight can tell you, it’s not easy making changes. However, in answering this question, we can identify what the evidence really says and how it can help guide us in healthy living.

Let’s first start by clarifying that obesity is defined as excess body fat, not excess weight. Obesity has always been part of human society going back thousands of years, so it’s nothing new. What is new is that over the past 30 years, the proportion of people with obesity has climbed dramatically.

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Now, let’s ask a much simpler question: Is it better to be obese and active (or in good fitness shape) than be obese and not active and not in good shape? The vast majority of research would say yes. Whether it’s being regularly active or having a high fitness level, these two things lower your risk for early death and heart disease compared to people of equal body size who are inactive and out of shape. Basically, being active and in good shape is good for you regardless of body size.

What about compared to people who are an ideal body shape but aren’t active or physically fit? A recent review collected data from a variety of studies and concluded that:

  1. for both men and women, increasing amounts of body fat results in increased risk for early death,
  2. higher fitness levels are associated with lower risk of early death, and
  3. that people considered obese and fit actually had a lower risk compared to people who were ideal body size but unfit.

As a result of these findings, researchers have tried to further define the different group combinations of being obese and fit, and have created the term metabolically healthy obese (MHO). These people may be obese but do not have risk factors for heart disease like high cholesterol, high blood sugar and high blood pressure.

While these people may have a lower risk for disease than similarly obese people with risk factors, being MHO is not without concern. Compared to people at ideal body size, who also have no risk factors, MHO have greater calcification in their coronary arteries, a sign of early atherosclerosis. A more recent study found that MHO people had a 50% greater risk for heart disease as well. So while being MHO is better than being obese with risk factors, it is not better than being ideal body size with no risk factors. The focus on metabolic health also misses other concerns with obesity such as arthritis, back pain, as well as the psychological and social issues of obesity as highlighted in an earlier blog.


Conversely, it’s also possible to be lean but at high risk for disease. These people are referred to by terms such as thin on the outside but fat on in the inside (TOFI) and metabolically obese but normal weight (MONW). These people tend to have a number of risk factors for diabetes and heart disease, and are in poor shape and have more fat around their waist and organ. Together, this puts them at greater risk for heart disease and early death.

So where does all that leave us? Getting back to our original question, one study did find that overweight or obese fit people had similar risk for early death than lean fit people. However, this finding isn’t consistent among all studies, and a much larger study reported a 90% greater risk for early death in obese, fit women compared to lean, fit women.

The bottom line is that both obesity and being physically inactive (or out of shape) increases risk for a number of diseases and early death. However, the lean person who doesn’t exercise may not be in such good shape after all.

exercising- small

Therefore, being active and in shape at any size is good for you. And given the challenge of weight loss, focusing on regular activity is a sure way to improve your health. While worrying about weight or body size may not be ideal unless your physician considers it to be a problem.

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