O que significa o phrasal verb wean someone off something?

I've been on a diet for a week. It might sound like little time to some but it feels like an eternity to me. If you've been through a very restricted diet like mine and you're just a regular person who likes to pig out on junk food, you know what I mean. And that's my exact situation. Since I discovered some Nutella milkshake at a certain brazilian fast food restaurant I've been down on a slippery slope (or maybe until a week ago).

One of my friends was the reason why it finally hit me I should do something about my diet. He suggested that I go to the gym and go for evening walks with him. He also said he was going to try to wean me off junk food.

If you wean someone off an addiction or bad habbit just like my friend did to me, you make them gradually stop depending on it. 

I don't know if that'll work, but it's always positive to try to engage into healthier habits. But what about you? Have you tried to wean a friend off a bad habit? Maybe you were the one who had your habits changed? Let me know in the comment section. Talk later.