Could this also be translated as 'Your diet is bad?' I know that literally they mean different things, but 'diet' is more commonly used. Can Ernärung also mean diet (meaning the kind of food that you eat, not a way to lose weight)?
Dict.cc suggests it (PONS doesn't, however), so maybe you can in some contexts - but it doesn't really work in this one. "Your feeding is bad" doesn't make much sense in English, and "feeding" isn't really synonymous with "diet" or "nutrition".