doesn't the size of the family almost completely account for the difference in price? say you do a simple, stupid analysis - 12k / 3 = $4k/person/year, which i

doesn't the size of the family almost completely account for the difference in price? say you do a simple, stupid analysis - 12k / 3 = $4k/person/year, which is greater than 17k/5 =$3.4k/person/year of course, that's not entirely fair, since children eat less than adults, right? if you ballpark daily caloric intake, the family of 3 eats (2500+2000+1000)365 calories a year, for 4.4 cents/Cal. The family of 5 maybe eats (2200 + 1800 + 1800+1600+1000) 365, for 5.5 cents a Cal (I'm assuming the aging adults moderate their diet for their decreased metabolism) yes, that's a 20% increase, but given other factors (possibly more dining out, errors in the ballparking, etc.), it's really not a huge jump in food prices.