Watch Your Arithmetic!

According to a news item in Common Knowledge edited by Robert E. Ornstein (a collection of weird news from the late 1960s and early 1970s), South San Francisco High School once ran an experiment to teach their victims/students about starvation. As a result:

Groans of sympathy rose up from all corners of the room, echoes of hunger from the 30 students taking part in a three-day experiment to dramatize the world's food shortage problem.

For 72 hours, they are existing on a daily intake of 266 calories, the amount they claim each person would get if all the world's food were equally distributed.

Say what??? Out of what bodily orifice did they get they get that figure? Did they subtract 2000 calories from the actual figure? Did they skip a decimal place? (2660 calories sounds high but it might be the amount if you add the food consumed by domestic animals.)

Why didn't anybody notice that amount was absurd? Did they calculate the right figure but assumed that starving Third World people couldn't eat that much? Did it occur to them that an amount of food that would be barely adequate for somebody doing heavy manual labor would fatten up a couch potato?

What were the long-term effects of this and similar programs? Does much of the opposition to open borders (or free trade for that matter) come from people who actually think they'll be living on 266 calories per day in a borderless world?