The following is a quote from an article in the New York Review of Books "Godot Comes to Sarajevo" (Vol XL #17, pp 52-59, October 21, 1993) by Susan Sontag. (Not online, unfortunately.) She went there to put on the play "Waiting for Godot" when Sarajevo was under daily bombardment--people wanted artistic diversion as much as they wanted food. The quote is a very brief aside from the main topic.
The only actor who seemed to have normal stamina was the oldest member of the cast. Ines Fancovic, who is 68. Still a stout woman, she has lost more than 60 pounds since the beginning of the siege, and this may have accounted for her remarkable energy. The other actors were visibly underweight and tired easily. Lucky must stand motionless through most of his long scene but never sets down the heavy bag he carries. Atko, who plays him (and now weighs no more than 100 pounds) asked me to excuse him if he occasionally rested his empty suitcase on the floor throughout the rehearsal period. Whenever I halted the run-through for a few minutes to change a movement or a line reading, all the actors, with the exception of Ines, would instantly lie down on the stage.
Another symptom of fatigue: the actors were slower to memorize their lines than any I have ever worked with. Ten days before the opening they still needed to consult their scripts, and were not word-perfect until the day before the dress rehersal.
It ought to be obvious to anybody that Ines was energetic not because of weight loss, but because she had the weight to lose. Note that she is
still fat after having endured severe famine conditions for a couple of years. It seems to have been much easier for her to tolerate going from 300# to 240# (my guess) than for Atko(hypothetically) to go from 160# to 100#.
This tells you why some people are fat--more of their ancestors than usual had to withstand conditions like this. It pays to have at least a few people in every society who are still mentally alert and physically capable under conditions that make metabolically normal people weak and stupid, even if they have major disadvantages when times are good. Sure looks like at least one fat old lady could really sing it during bad times.
If you have a metabolism like Ines, the only hope for coming close to "normal" weight is a lifetime commitment to recreating the famine conditions your ancestors were genetically adapted to, and for many people that isn't going to be feasible.
The health nazis think that fat people ought to be required to live under a permanent state of siege, Sarajevo or the equivalent forever. What if you would prefer to have an actual life?