Story Research

Study Gives Weight to Hormones

Elizabeth Chapin



When men and women begin an exercise regimen, men typically lose weight quickly, and women tend to have more trouble shedding those extra pounds. A recent Cal Poly San Luis Obispo study may provide an explanation to the weight-loss gender gap.

Exercise normally boosts the metabolism, serving as a natural appetite suppressant. But research led by Todd Hagobian, assistant professor in kinesiology at Cal Poly, provides evidence that this benefit only occurs in women who are already lean.

Hagobian’s study indicates that overweight women produce more appetite-inducing hormones after a workout. And the increased calorie consumption can turn all of the hours and calories lost at the gym into a lost cause.

Hagobian and a team of Cal Poly student researchers tested appetite hormones including insulin, ghrelin, and leptin on 20 men and women during rest and exercise conditions. The goal was to determine whether exercise increased appetite-boosting hormones and food consumption in women but not men.

In the study, the men and women were invited to an open buffet-style meal following a 90-minute workout. The participants were then invited to eat whatever they pleased. Student researchers working in Hagobian’s lab measured their hormone levels and calorie consumption. Then they performed all of the data and collection analysis—which lead to some unexpected and interesting results.

“The data shows that after the exercise period, both men and women experienced appetite suppression with no increase in appetite-inducing hormones,” Hagobian said. “They ate less than they did during the studies where they did not exercise.”

But Hagobian noted the young men and women participating in the study were already lean and fit, and further hypothesizes that it is only overweight women who experience the extra post-exercise appetite hormones.

Hagobian and his student researchers plan to present the findings at a national conference this summer. He’s also using the preliminary data as a basis for a future National Institute of Health grant, which would provide funding to allow the study to continue.

“We’d like to further understand fitness levels vs. weight status and what that means for calorie intake, particularly in women,” Hagobian said.

Hagobian’s study and similar research could ultimately lead to exercise regimens that include the integration of hormone regulation. But in the near future, it could help women become more conscious of calorie intake, as well as their bodies’ unique biological differences.