I don't have to guess at it at all.

They even give the quantities of calories of energy required for different sized men.

I'm going to measure you both to-morrow; and you must be weighed, too," she continued, ignoring the sniffs of remonstrance from her two listeners.
"Then I'll know just how many calories to give each of you.

They say a man of average size and weight, and sedentary occupation, should have at least 2,000 calories--and some authorities say 3,000--in this proportion: proteins, 300 calories, fats, 350 calories, carbohydrates, 1,350 calories.

But you both are taller than five feet five inches, and I should think you weighed more than 145 pounds; so I can't tell just yet how many calories you will need." "How many we will need, indeed!" ejaculated Bertram.
"But, my dear, you know I have to have my eggs," began Uncle William again, in a worried voice.
"Of course you do, dear; and you shall have them," soothed Billy, brightly.