You've heard the phrase, "You can't out-train a bad diet." Turns out that you also can't out-cologne a bad diet either.

In a new study, researchers wanted to see if women preferred men who ate cleaner diets over those who ate "dirty." Turns out, they really could sniff out the difference. In fact, the ladies found that men who ate more fruits, veggies, and meat smelled more attractive than those who ate refined carbohydrates.

So How is This Possible?

Our sense of smell affects us on a deeper level than we know. Inside your nasal cavity is something called the olfactory cleft. In it lies millions of olfactory neurons that connect directly in to the brain. It even seems that our noses can pick up on the diets, genetic information, and health statuses of those around us through chemicals released in sweat.

One study showed that humans preferred the smell of sweat of those genetically dissimilar from themselves, potentially as an evolutionary advantage to avoid inbreeding. Certain disease states also affect the way your sweat smells. If you're immunocompromised or infected by some kind of pathogen, your sweat also stinks more. And people around you know this.

Why You Might Still Be Single

In this latest study, researchers took a group of dudes, gave them some T-shirts, and told them to exercise wearing the shirts. The guys also filled out questionnaires that determined their "food frequency" or how often they ate certain groups of foods like fruits, veggies, oils, meats, seafood, and carbs.

The researchers also measured their skin yellowness with something called "skin spectrophotometry," a tool that measures skin tones. Eating more carotenoids (things in fruits and veggies) gives the skin a yellow tint, and this tint is considered more attractive.

After the guys got their sweat on, the shirts were given to women. Researchers asked them to rate the smell first according to liking, attractiveness, health, and intensity. They had other ratings for smell (animal/floral, fishy or chemical) but these didn't totally correspond to the attractiveness scores.

The Votes Are In

Men who ate more fruits and veggies passed the sniff test. Guys who ate a good amount of meat also passed.

The women were more attracted to the sweat from men who ate more fruits and veggies. And these were guys who really did eat more fruits and veggies as measured by the yellow hue of their skin. Good news for you carnivores, too. The ladies also found that those who ate more meat had more pleasant and less intense smelling sweat.

The researchers concluded that "sweat can serve as a further honest cue to women about a man's health status."

References

1. Andrea Zuniga et. al., "Diet Quality and the Attractiveness of Male Body Odor", Evolution and Human Behavior 38 (2017): 136-143.
2. Ivanka Savic et. al.,"Smelling of Odorous Sex Hormone-like Compounds Causes Sex-Differentiated Hypothalamic Activations in Humans", Neuron 31 (2001): 661--668.