This chart compares the body mass index (BMI) of superheroes in Marvel comics with those of typical American women and men. Researchers Karen Healey and Terry Johnson used physical stats from Marvel's Web site to show that the vast majority of female superheroes are underweight, though the males are mostly normal. Just to remind you, in the BMI scale, below 18.5 is underweight, 18.5-24.9 is normal, and over 25 is overweight. Healey's analysis of what this means is hilarious and thought-provoking.
The BMI range of Marvel women is much less varied than that of all other groups and tends to the low end of the "normal" BMI range. This result is surprising, considering that many of the women sampled are martial artists or extremely capable physically and should, if anything, have a BMI that indicates a higher body fat level than is actually present.
The BMI range of Marvel men is more varied and tends to just over the upper limit of the "normal" BMI range. However, it is still less varied than that of the "real world" male and female groups.
We stress that given the physical and biological vagaries of the Marvel Universe and the relatively small sample sizes involved, these results are not conclusive. Data comparing male and female athletes from both world might provide more accurate comparative results, and we suggest this as a point for further research.
However, advance data indicates that Marvel women are portrayed as having a disturbingly low BMI compared to the healthy BMI range of their male counterparts. Furthermore, the range of body types expressed by Marvel women is surprisingly small. The distribution of BMIs in Figure 1 is by far the sharpest, with little variation from the mean compared to Marvel men, and far less variation than we see in actual men and women. This is true to a lesser extent for males in the Marvel universe as well.
The Marvel male is predisposed to be on the heavy side of healthy, which can be explained by the increased muscle mass of intense physical acitvity. The average Marvel female is approaching underweight despite a presumably active lifestyle. This may corroborate sociological and literary observations that in the Marvel Universe, women must fulfil criteria for being attractive by Western standards before fulfilling the criteria of biological realism.
Of course, this is no different from what we see in depictions of women in the so-called real world, where magazines airbrush women's arms to half their size or Photoshop their faces to look slimmer. Here is my favorite part of Healey's paper, where she explains how they picked heroes of the appropriate age:
The "real" age of Marvel Universe persons is frequently altered by the powers or mutations of individuals, non-Euclidean time, cryogenics, magic, biochemical solutions, alternative dimensions, radiation, cloning and resurrection. The 20-29 year old age range was chosen as the most appropriate range comparison for the apparent physical age of most adult Marvel characters.