She's a bit young for puppy fat. I expect your daughter was so relieved when she started to enjoy her food after such a worrying start, she over compensates. She may also have inadvertently given your granddaughter some obsessiveness over food in general, as she may have been making it more important than it should be by encouraging her to eat previously. Dangerous ground isn't it, broaching healthy eating with your daughter without seeming to criticise her parenting skills. Also, don't forget, sometimes kids will go outwards, just before a growth spurt upwards. One of my sons did it the other way around (he's always been awkward!). Sounds like you're doing all the right things making sure she gets plenty of exercise. From your comment about struggling at sports day though, I wonder if she's actually quite a bit over weight and not just 'chubby'. If that's the case, maybe you could also, on the days you have her, start some 'fun cookery'. Buy her a kids healthy recipe book and instead of seeming to criticise, work with her to cook her own healthy stuff and make it fun (I saw a great one of these on a kids programme once, where they made stuffed peppers) and during these sessions, you could discuss with her (rather than criticise) the nutrition of the meals she's cooking and then perhaps she will pass this on to your daughter as something she enjoys. Worth a shot. You could say to your daughter you're teaching her to cook, rather than 'skinny up'. Mine field being a grandparent isn't it. As I've found. Treading that thin line between loving and caring and interference.