The Globe and Mail reports in its Thursday edition that since U.S. President Donald Trump took office last year, his tariffs have gone after steel, aluminum and autos; next up: protein. The Globe's Kate Helmore writes that when the Trump administration last week announced coming 50-per-cent tariffs on hundreds of Canadian products, the list included a range of proteins, such as whey and other dairy proteins. The White House cited specific "discriminatory" rules within Canada's supply-management system for the duties, which would take effect Aug. 19. This batch of tariffs would affect more than $200-million (U.S.) worth of protein exports to the United States, the majority dairy-based products. It's just the latest example of how the U.S. has taken exception to Canada's supply-management system, a model that curtails production and imports. These measures would affect Canada's three largest dairy processors -- Agropur, Saputo and Lactalis. But in targeting dairy protein, Mr. Trump is also heaping extra costs onto massively popular products at the centre of a cultural craze. There is a global demand boom for protein, driven in large part by "manosphere" fitness influencers and the introduction of weight-loss drugs.