In rare circumstances foods can cause gynecomastia. This is because some foods naturally contain high levels of phytoestrogens, chemicals which closely mimic estrogen and can ‘trick’ the breast tissue into growing in response. High levels of phytoestrogens are found in a range of foods, especially those with high levels of soy protein. Men who are most at risk for this cause of gynecomastia are those who obtain a lot of their protein from soy – particularly those following a vegan diet. If men think that food might be responsible for their gynecomastia, they should carefully look at how much soy they are eating in things such as tofu and vegetarian meat alternatives. It is worth checking the ingredients in commonly eaten prepared foods, as many producers use soy protein as filler in packaged food.