Two-thirds of of American adults are overweight or obese. With overweight being more prevalent than healthy weight, the perception of what is considered "normal" weight is skewed. 

I recently saw many examples of this on a forum where someone posted a picture of a woman in her underwear. The woman had a BMI slightly higher than 30, classifying as obese. Yet many, if not most, commented by saying that the person in the picture was not obese. Chubby perhaps, but not obese. Some did not believe her body weight was as high as stated. A considerable number of people compared the body in the picture with their own, and that may be part of the problem.

In a study about body weight perception 82% of obese women and 43% of overweight women underestimated their weight. Only 13% of normal-weight women underestimated their weight. This may explain why some people have trouble realizing that they and others are overweight.

People tend to make excuses for their weight, saying they are "big boned" or have a higher muscle mass than others. The truth is, our skeleton accounts for only 13-20% of our body weight. As for muscle mass, muscular individuals can have high body weight due to the higher density of muscle compared to fat. It is however very rare for a woman with healthy body fat to have high BMI due to having high muscle mass. An example of a non-fat woman with a BMI classifying her as overweight is Ms. Iris Kyle, a professional bodybuilder. She is 5'7'' (about 170 cm) with an offseason weight of up to 170 lbs (about 77 kg), making for a BMI of almost 27, which is classified as overweight. In order to rightfully claim that one is overweight due to high muscle mass, one must look something like a bodybuilder, which is of course not the case for the vast majority of people with high BMI.

With obesity slowly becoming the norm and an increasing number of people suffering from preventable obesity-related diseases, it is clear that something has to be done to change people's perceptions of healthy weight. The current efforts to educate people about healthy habits are futile as long as people's beliefs about what is healthy and what it looks like are faulty. 

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