WASHINGTON (CBS DC) — Macho features may be viewed favorably by women, but their linking to weight problems is far less attractive to many women.
The new study suggests that while women do prefer the faces and bodies of men with strong immune responses – linked to macho features — they seem to cue into fatness and thinness far more negatively, when making their judgments.
Macho features such as a strong jaw and squinty eyes present a man’s high testosterone, according to the “immunocompetence handicap hypothesis.” Because high levels of this masculinizing hormone interfere with the immune system, the theory states that macho men must be extra-fit to withstand the handicap their extra testosterone gives them.
Fatness, or adiposity, “is an obvious choice for a marker of immunity because of its strong association with health and immunity,” study researcher Vinet Coetzee, a postdoctoral scientist at the University of Pretoria in South Africa, told LiveScience.
However, the immunocompetence handicap hypothesis is problematic because masculinity is not universally attractive to women, Coetzee and his colleagues wrote today in the Nov. 27 issue of the journal Proceedings of the Royal Society B. Nor have studies consistently linked macho features with good physical health.
Weight is acutely linked both to health and immune system functioning, Coetzee told LiveScience. Both overweight and underweight individuals are more likely to have health problems and poor immune function.
To test the evolutionary role of fat, Coetzee and his colleagues first photographed 69 Caucasian male volunteers in underwear. They also measured the men’s body fat and testosterone levels. About 65 percent were healthy weight, 4 percent were underweight and 30.4 percent were overweight or obese.
Next, 29 heterosexual Latvian women looked at photographs of the men’s faces and bodies separately and judged them on attractiveness. All of the women were in the fertile phases of their menstrual cycles, as judged by counting back from the last menstrual period to the day of likely ovulation.
A separate group of 20 heterosexual Finnish men and women rated the men for masculinity, and 14 other Latvian women rated the men’s facial fatness, or adiposity, which is highly related to overall body fatness.
The results revealed that fatness, as measured with facial adiposity, was linked to both antibody response and attractiveness, with pudgier men both having weaker immune systems and being seen as less appealing by the fertile women. A statistical analysis found that — contrary to what the immunocompetence handicap would suggest — masculinity was not linked to either immune response or bodily or facial attractiveness.
While the findings don’t view a masculine jaw and defined abs as a sign of a good immune system, Coetzee warned that the study looked at just a single measure of immune response. The researchers also don’t know if women had immune health in mind when they made their hot-or-not judgments.