edit for the knee-jerk downvoters: Everything the government is authorized to do is codified in federal statute, including agency powers. If Congress doesn’t give an agency the power to regulate the size and shape of a peanut butter cup, the agency cannot regulate the size and shape of a peanut butter cup, full stop. The reason the President isn’t proposing a fix to this is that Congress hasn’t given anyone the authority to fix this problem. The FDA can sorta kinda regulate slack fill (i.e. the empty space in your bag of chips) but only if it’s non-functional or deceptive. Shrinkflation is quite legal, so long as the size/weight of the product is clearly labeled. If companies get away with it, that’s because we’re stupid, clueless consumers who never read labels. And they will continue to do it until a) we stop buying their product, or b) Congress passes a law to make it illegal. Unless that happens, we’re stuck with it because the President is not an all powerful god who can will things into existence.
Once again, civic literacy in this county proves profoundly lacking.