R.J.
Minus the anger... yeah... in my family. You teach manners surrounding asking for anything (just a part of parenting)... but just as an example, my son:
Avg of 20oz of breast milk every 2 hours (apx, fed on demand) as an infant... so around 150-200oz a day until 9-10mo
Avg of 64oz of formula per day from 10mo-18mo, solids started at 1 year... but he was growing too fast for table food, so we supplemented with formula for some time.
Right BEFORE a growth spurt (from infancy to age 9) he eats CONSTANTLY. Double what my husband eats (about 4,000-6,000 cal). He chubs up like the Stay-Puff-Marshmallow man. And then after about a month of gorging, his appetite stops on a dime and he eats about half of what I eat (about 1,000 cal). He shoots up 3 or 4 inches over the next 2 months, and then he's pure ribs and vertebre and little 8 pack and braided back. Which is just an odd look, but whatever. That's the pattern, though: Pudges out, shoots up.
That's just the normal growth pattern in my family. We get to reuse a LOT of clothes, because we buy "big" and roll cuffs. Pants start getting all tight around the middle... and then in a month, we're strapping them on with belts to keep them from falling off and the cuffs have been unrolled and they're "highwaters".
My family's scandavian, and we're usually at our full height by age 12/13. For girls that's 6', for boys that's 6'3-6'6.
Nearly everyone in my family is reeeeeeally active. For the athletes (practicing) we're talking 8,000-12,000 calorie diets as kids to keep up with both the extreme growth AND the physical demands placed on them. The boys (well, girls, too... but it's something more wanted on the boys side), strap on muscle like they're on anabolic steroids. At age 12/13 most of us look like we're in our early 20's.
Thank GOODNESS we've had the same pediatrician for years. Whenever we get a substitute the weight thing comes up. Either overweight or underweight, depending on where he's at in his growth cycle!!! I just smile and ask them to look at his charted height/weight in the past.
((My ped ditched American height/weight chart for my son shortly after his birth. At 10lbs & 23.5 inches at birth he was in the upper bit, but by 3mo he was off the chart and has stayed off ever since. So my Ped changed charts and downloaded a Swedish or Norweigan one (I kinda forget which). Which places my son at about 60th percentile for height/weight.))
Now... like I said... this is TOTALLY NORMAL for MY family. There can be medical conditions (worms, parasites of other kinds, disorders, diseases) which cause extreme hunger as well. Most commonly here, though, it just tends to be 'fast growers'.