They want smaller, well-defined stomachs. Women want smaller hips and thighs. Men are more likely to conceal their disordered eating. Men with disordered eating seem to be more likely to diet because they are frightened of future medical problems attributed to being overweight. Boys grow up with as many concerns about being too thin and short as they do about being too fat.
Girls grow up mostly having concerns about being too large.
Although testosterone does decrease in males with eating disorders, especially anorexia, there is no clear marker of hormonal dysfunction like there is with females. Women with anorexia or excessive exercise problems develop amenorrhea or loss of menses. In the gay male community it appears that body image is often more important for being attractive than it is in the lesbian community. Boys with eating problems seem to have more gender conflicts. Male anorexics seem to have anxieties about masculinity and athletic performance.