My friend is having severe problems with her extremely aggressive and violent 2 year old. He's an absolute nightmare and she's always covered in bites, scratches and bruises. She is reasonably strict with him and loves him to pieces. However, every time I see him, he has a chocolate bar or ice-cream in his hand. His diet is primarily chicken nuggets or McDonalds. Could his appalling diet be affecting his behaviour and would I be stepping over the line by drawing her attention to it?