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You choose: “Skinny and Fat” or “Fat and Fit”

April 6th, 2007

I got this article sent to me in email and I thought it was interesting, so I figured I’d share it.

The basic issue that the article discusses is the fact that people who appear to be skinny and have a relatively normal Body Mass Index can actually have too high of Body Fat percentage. The article points out that “you could still be at risk for cardiovascular disease and metabolic syndrome if your fat mass is greater than 30 percent of your body weight. “

I’ll admit, that this concept of a low BMI with a high % of body fat seems very unlikely to me, but apparently it’s common enough to have a syndrome named for it: normal-weight obese syndrome. The basic idea is that you may have a low BMI, relatively low weight, but actually have a high percentage of body fat. When your body fat is greater than 30% you’re considered obese. So for example, a 5′3″ woman who weighs 136lbs would be have a normal BMI, and would be considered in the normal range for weight. But if she has a 34″ waist, she would be considered at increased risk for weight related health issues. If her larger waist is due to higher body fat percentage, then she may have normal-weight obese syndrome.

We all know the risks of being obese, and those same risks exist for people who have normal-weight obese syndrome. Although undiagnosed, those people may be more likely to assume they are healthy, since they look skinny. How do you combat this health risk? Of course, you all know already: cardiovascular exercise, strength training, and a healthy diet.

Now, another common example of how BMI can lead you wrong, is when someone is very fit, with lots of muscle mass, and as a result their BMI is actually higher than their body fat. Since BMI only measures the ratio of your weight to your height, and muscle is heavier than fat, your BMI would go up as you convert fat to muscle as part of a fitness program. Of course, if you are going from a typically overweight body to a more fit body, you are very likely to lose some weight in the process. But if for example you simply converted fat to muscle (and of course your height didn’t change) you could actually increase your BMI while you became more healthy. Let’s say you were a 5′4″ male weighing 154lbs, with a 27″ waist, this would not be unusual for someone who has done strength training and was relatively muscular. But would equate to a BMI of 26.5 which, when only considering BMI, is considered a risk indicator for being borderline obese. In fact a typical disclaimer for BMI calculators will say something like this… “Unless you have considerably more muscle and less fat than most people…” Maybe even more obvious is the fact that to achieve an ideal BMI for a 5′4″ person you have to have a weight of 128lbs. That’s 12lbs lighter than I am, am I unfit? I think not.

So here’s the question… is it better to be “skinny and fat” or “fat and fit”? Well, if by “skinny and fat” you mean skinny as measured by BMI but fat as measured by body fat percentage… it seems this is not a good place to be. But if by “fat and fit” you mean fat as measured by BMI and fit as measure by cardiovascular fitness, body fat percentage, and ability to complete various athletic events… well… I think you know which one I would choose.

Entry Filed under: Fitness, Diet, Weightloss, Strength Training, exercise, science