I have skinny DC's too still - DS's are real sugar addicts, no stop button as far as I can tell, DD (middle child, just 6, no mention of body image etc wrt food so far and long may it continue) just doesn't seem to have the same compulsion with sweet stuff, she asks for it I think because the boys make such a fuss about it but then she invariably leaves half the sweets/ice cream whatever it is. It reinforces my feeling that different people respond differently to powerful substances such as sugar, caffeine etc and that food addiction (to specific substances such as these, rather than 'food' full stop - that would be a bit like oxygen addiction
) can affect people.
On the subject of body image, I have to share a conversation I had with DD and DS2 when we were cuddling in bed the other day, DS2 was blowing raspberries on my belly, his favourite pastime 
DS2 - Mama I love your belly, its so soft...
me - I love my belly too, because it looked after you three kids when you were babies before you were born - DD, what part of your body do you like?
-dd - I like my eyes because I can see with them and my nose so I can smell, and my arms and legs that let me run and do gymnastics and exercise
-me - what about you DS2?
-DS2 - no hesitation....I like my penis.
- well I guess it's what most men would say if there were no adult/social filters operating
. It was utter unequivocal way he said it that had me ROFL!