mother in law driving me crazy! (sorry long rant)

So my youngest son is 5 months he's going to be 6 months in a week and I decided to start giving him baby food not a lot maybe 3-6 spoons so he can start getting use to it. Well after I feed him a little. It we went to his moms and she's like "oh you started giving him baby food" (he still had some on his face) and I'm like "yes I want him to get use to it" she's "like that's good!". I swear I feel like this bitch heard I'm feeding him everything. Not long before she starts holding him she starts giving him freaken chocolate it pissed me off so bad they know I'm against giving baby junk food like that and her excuse "my house and I'm grandma" like ugh she knows how much I hate it and they never ever respect my wishes! 
The only reason why I'm mad about the junk food it's because my sister in law lives there I swear before her daughter was even 1 years and a half she was drinking coffee, soda, eating so much candy it was ridiculous! 
I just don't know what to do with her anymore she tried pulling the same crap on me with my oldest. 
(Yes my husband knows how he feels but he won't tell her shit)