In grad school, I managed to eat pretty healthy on $20/week. I'm hypoglycemic, so eating processed junk would result in a hospital stay. Most of what I made took a lot more effort than making processed food and usually tasted worse. I was working and studying 60-80 hours a week and never liked cooking. But being willing to forgo short term pleasures for long term gains was the reason I was in grad school in the first place.