How to politely deal with people who don't agree with your parenting style/rules

Hello! I have a 3 year old daughter and have been reasonably strict with her diet (no chocolate, candy, soda, etc.) but find it so frustrating when others tell me I should lighten up or that it won't do her any harm. Some extended family members even give her sweet treats when my back is turned! My daughter is very well behaved, and I put a lot of that down to her diet and the lack of sugar spikes and crashes. I realise that she will eat these things eventually (she's already had small tastes here and there) but I don't want them introduced daily or as "treats". What do you do when you get unsolicited advice, and even acts of sabotage? I've made my position clear, but I feel like certain members of the family are being blatantly disrespectful in disregarding my way of doing things. via /r/Parenting http://ift.tt/2eeipsb