Can you help my 7 year old daughter with weight problem?

She weighs about 77 pounds. She doesn't eat alot of junk food and we've cut out soda and candy almost altogether. Our family is large and always seems to be on the go to one activity or another. We don't "eat out" alot and I try to cook good wholesome meals. Her school phys ed program only allows an hour of structured activity 3 times a week. Any suggestions on helping her drop a few pounds. She is getting teased at school and I'm at a loss as to how to help her. We went to a dietary specialist last summer - added fibre was the suggestion. So far, very little change. Her 5 siblings are all within a normal weight range.