Buy her a trampoline. My kids love it, it's the best thing we have bought in terms of fun and exercise. Bounce together on it. Do 100 jumps a day.
Get her to help with the tidying/ hoovering / dishes everyday before bed. This will help you/ get her moving and give you more time to exercise at the weekend.
Get her to follow a dance video instead of going on the iPad.
Make her earn every treat!
Get rid of all sugary snacks in the house. Maybe have one every Friday as a family treat.
Talk to her in terms of sugar being bad for her teeth not bad for her weight. Don't mention her weight ever!
Remind her that she has a smaller portions because she is half the size of an adult.
Or add more veg so her plate looks fuller.
Always buy plenty of cucumber/carrots/peppers to slice with humous /brown pitta bread/ rice cakes/toast to snack on after school.
Toast and egg /(low sugar) beans for breakfast. Easy!
Healthy snack for school. So she's not so hungry at 3.
NO snacking after dinner or in between designated snack times except for fruit or sliced veg.
Stick to it and be determined. You can do this!