I'm thinking of stealing most of my groceries
Are you seriously considering that? Why would you steal food?
I'm too lazy to prepare meals myself.
Stealing just because you're lazy can cause consequences for not only you but for others as well. Store owners have to spend more money to protect their things, which makes prices go up for paying customers.
I'm only stealing a shit ton of junk food. It's not like it's food for a child.
Just because it's unhealthy food, doesn't mean it's right to steal it. Hardworking people farmed and processed that food, how would they feel to have their hard work taken for free? How about starting small and trying to cook one pot meals, it can be fun!