Plants that are in the Brassica genus, including broccoli, cabbage and cauliflower, can affect body odor because of the vegetables’ sulfur compounds. So can foods in the Allium genus, which include onions and garlic, also due to their sulfur compounds. To see how pungent these compounds can be, try this experiment: rub crushed raw garlic on the sole of your foot—within about 20 minutes you’re likely to taste it in your mouth. If you like garlic but not the mouth odor, try drinking milk after eating it. A 2010 study in the Journal of Food Science found this may help.
Going meatless may have some olfactory benefits. In a small study published in Chemical Senses in 2006, women rated men’s body odors (taken from their armpits) as more attractive and pleasant and less intense when the men ate no meat for two weeks, compared to when they consumed red meat. But it’s not clear how much meat you have to eat for it to affect body odor, how long the effects last or whether fish or poultry have a similar effect.
In some cases, there is an interaction between your genes, diet and body odor. For example, people with the inherited metabolic disorder trimethylaminuria develop a fishy odor when they eat fish and some other high-protein foods. This is due to an inability to break down a food-derived compound (trimethylamine), which then builds up in the body and is released in sweat, breath and urine. Though the disorder is rare, the authors of a 2007 paper in the Annals of the New York Academy of Sciences found that many people with unexplained body odor tested positive for it.
Though not a body odor issue per se, asparagus is notorious for making urine smell funny—somewhat like rotten or boiled cabbage. It has long been debated whether only some people are capable of producing the odor or whether all people make it but only some people can smell it. In a 2011 study from the University of South Florida and Monell Chemical Senses Center, researchers confirmed that people differ both in their ability to produce the odor and in their ability to perceive it, due to genetic variations. This is certainly no reason to stop eating asparagus. No one but you is likely to notice it.