Saigal of the University of California at Los Angeles, who was not involved in the study, told Reuters Health in an interview.
Saigal noted "weight loss is a goal for all of our obese patients," because it can improve many health indicators, such as blood pressure and cholesterol levels.
But for patients, these benefits of weight loss are often "intangible," Saigal said.
Weight loss can provide tangible benefits to obese men, according to the UCLA physician, who is the author of an editorial that accompanies the study in the Journal of the American Medical Association.
"If you lose the weight, you may regain sexual function," Saigal said.
"That's a carrot for an obese individual.
" But, Saigal pointed out, "This study does come with a caveat.
" The participants did not have high blood pressure, diabetes or other health problems that may make weight loss less effective for improving erectile dysfunction, he said.
In the 2-year study, a team led by Dr.
Katherine Esposito of the Second University of Naples followed 110 obese men with erectile dysfunction.
Half of the men were randomly assigned to participate in an intensive weight-loss program that included individualized advice on boosting exercise and improving diet.
The other half received general information about healthy eating and exercise, but did not receive any individualized guidance.
By the end of the study, men in the intensive group achieved significant weight loss, along with improvements in several health indicators, such as blood pressure and cholesterol levels.
What's more, 17 men (31 percent) in the intensive group regained sexual function by the end of the study, compared with just 3 men in the other group.
"Our data demonstrate that lifestyle changes, including a reduced calorie diet and increased exercise, improve erectile dysfunction in obese men," Esposito and her colleagues conclude.
"Interventions focused on modifiable health behaviors may represent a safe strategy to improve erectile function and reduce cardiovascular risk in obese patients," the authors state.
Saigal agreed that weight loss is "a great first-line therapy" for erectile dysfunction.
Losing weight will not hurt patients, he said, and if it doesn't improve erectile dysfunction, there are several drugs on the market that may be helpful.