I already feed them every 3 hours
We are going to have to agree to disagree in regards to caloric intake and daily exercise cause IME it is VERY relative .... a body that has a high muscle mass because it is 'active' burns more calories in general and even more so when they are active and therefore NEEDS more calories to sustain it verses a body mass that is low in muscle mass and higher in 'fat' .... my spouse was a body builder when he was in the army and when he was training he would eat 3 times a 'normal' person at a sitting just to sustain himself...even now that he no longer active he still eats more than a 'normal' person however is muscle:fat ratio is still very high - he burns more calories so if he does not eat hearty at meal time he 'looses weight' just doing nothing - drives me nuts!
So in comparison a child who is ALWAYS active and therefore has a very high muscle mass verses body fat in their metabolism is yes either going to have to eat a normal meal EVERY HOUR which lets face it is not possible in a group setting or is going to need LARGER SERVINGS at their normal meals/snacks every three hours .... honestly I am not exaggerating when I say my crew is very physically active - we are outside 2-4 hours out of our 9 hour day almost every day and they are not just active in daycare but they are in extra curricular activities like swimming, soccer, karate, gymnastics and so forth ... some of the poor things are in something almost EVERY NIGHT ... so their appetites are normal for their activity level - they need that many calories to just maintain ... when they hit a growth spurt they eat MORE on me!