AITA for not standing up for my daughter and I when people keep commenting on our weight?

I have struggled with my weight my whole life. So has my daughter Lucy (10). I'm a single parent and I have two other kids; Tom (13) and Rachel (7). They are both thin. I have a difficult time saying no to food and drinks I know aren't good for me and I've transferred some of those habits to my daughter. We both love baking and the food we make is just too good to resist and we eat a lot of what we make. Rachel is also a little chubbier than average, but only slightly.<br><br>My parents have pointed out my weight constantly since childhood and now those comments have transferred to my kids. They've always said things like, "You're making her fat!" or "She's going to have a heart attack at 30 if she keeps eating like that." I've always responded with, "You don't have to worry about that. You don't have to pay her medical bills." Which has led to several huge fights.<br><br>However, I had an incident recently that really made me examine the dynamic between myself, my parents, and my daughter and I am wondering if I should have stood up for myself and my daughter in all these situations. We went to a family potluck at a park. I brought 3 desserts and my daughter brought a batch of cookies she'd made. My mom immediately came over to me and said, "You really made 3? Your daughter is already overweight and you're making 3 desserts? You really didn't have to bring all that!" I got a little pissed off because I had spent all morning making it and I felt like I was being criticized for doing something nice. So I "sarcastically" said, "Wow, you're right. I didn't think about how much weight we'd gain from eating cake once a month!" And then she said, "This isn't the first cake you've eaten this month, is it?" And I got really pissed off and said, "Look, these are the things we enjoy. Back off!" And then she said, "Fine, but I can't bear to watch your daughter get any bigger. You're setting her up for a life of obesity and you're going to be responsible for her early death."<br><br>Then I got really angry and I said, "So you're saying that I should stop letting her eat cake? Or should I stop making it? Because every time I make cake, she wants a slice. I've been telling her not to eat it at all, but she won't listen. Maybe you should talk to her!" My mom started to get this surprised look on her face and she said, "What? No, it's not her decision. She's a child. It's your job as a parent to keep her healthy, whether she likes it or not." So I said, "So...I don't know...make her a salad or something?" But then my mom got mad and said, "You can't even take care of yourself. You can't take care of her! What kind of mother are you?" And with that, I just said, "fuck it" and I went and got a slice of cake and sat down and ate it. My mom just looked at me and I could tell she thought I was being petulant and immature. But she dropped it.<br><br>The entire incident made me feel bad for some reason. I think it's because I felt like a kid again, like I was standing up for myself but in a really stupid way. It was also maybe the 20th time my mom had said something along the lines of "You can't take care of yourself or your daughter." I've always thought she was just being mean, but maybe she had a point. I feel like I was standing up for my daughter and I in a situation where someone was criticizing us, but was I? Was I really standing up for us? Or was I acting like a bitch? AITA?