I don't doubt that is true. And I can guarantee you that I was a super active kid as I grew up in pre-computer days when children went outside to run, roller skate, play ball, etc.
However, my point is that through history there has been many theories in medicine that have ultimately been disproved. Many people have similar experiences to mine and CW doesn't study it or try to explain it. They dismiss it as overeating as is frequently done here. That is too simplistic to explain my experience or that of many others.There is quite a lot in the literature now that points to modern wheat as one source of weight gain and for many even a small amount of sugar is a kind of poison. All I can share is my experience: cutting out grains and sugar (and for some time potatoes as well) helped me lose 70 pounds that I was never able to lose with much effort in the past..