If there were a scientific conspiracy to turn men into cuddly, highly evolved salad-eaters, oxytocin might be a powerful weapon.

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First, we learn that the “love hormone” oxytocin makes men more trusting, nurturing and sociable. Then, we learn a shot of the stuff makes partnered men less likely to stray or even flirt with other women. Now, we learn that a puff of oxytocin up the nose makes men eat less, and choose foods that are less fatty.

If there were a scientific conspiracy to turn men into cuddly, highly evolved salad-eaters, oxytocin might be a powerful weapon.

A study released last week found that 25 healthy men who got a dose of aerosolized oxytocin and were then offered a man-sized serving of breakfast consumed fewer calories, decreased their fat intake and showed improved measures of metabolic function such as insulin sensitivity.

The study, led by Harvard Medical School’s Dr. Elizabeth Lawson, is to be presented in San Diego on Sunday at the annual meeting of the Endocrine Society, a leading group of hormone experts.

The men served as their own control group: during one session a subject would receive a puff of oxytocin; at another, he would get a placebo.

“Our results are really exciting,” Lawson said. Although she said further study would be needed, she suggested oxytocin might be “a promising treatment for obesity and its metabolic complications.”

Oxytocin’s role in fostering sociability has led to its preliminary use as an aid to teaching those with autism improved social skills. But new research is broadening understanding of the hormone’s powers: Another recent study suggested oxytocin, which counteracts the inebriating effects of high alcohol intake, might help in the treatment of alcoholism, and possibly other addictions.