A.L.
hello
we have the same problem. I used to think that weight was NOT inherent but now I know differently. My son has always been on the bigger side and while I can say that we don't do a lot of junk food (ok, many will say, yeah right) it's true.. what I can tell you is this, in order to plow away at his weight (he's about 7-10lbs over) we have had to UP the exercise... The problem of weight began to rear it's ugly head even more so when he entered Kinder.. hence, all the sitting they do with barely much recess/P.E. (two things I happen to consider important) So what do we do differently, we walk as many places as possible.. to and from school... we walk on the weekends, for Summer Vacation, we averaged approximately 30 miles a week... We've also stopped any late night eating, not that we ever did much, but what little we did, we took out.. by changing up my son's routine, so far we have shaved off about 4 lbs.. I don't want to over do things either as he is also tall for his age and very broad shouldered, but I am happy to say.. the changes are working. Previously, he was also in Karate' 3xs a week, that was helping too, but eventually he tired of it..
now he is in swim lessons. Anything a little extra you can do outside of his regular routine will help.. best of luck