I think Dr. Hirsch came up in Good Calories, Bad Calories as one of those afflicted by blindness and does more non-science than science. As a matter of fact, that applies to most "researchers" in the obesity field.
to wit from the book -
"Once Hirsch's obese subjects took to restricting their calories, however, they experienced what he called "all the physiological and psychological concomitants of starvation." A semi-starvation diet induces precisely that - semi-starvation - whether the subject is obese or lean. "Of all the damn unsuccessful treatments, " Hirsch later said, "the treatment of weight reduction by diet for obese people just doesn't seem to work.""
"Francis Benedict, Ancel Keys, George Bray, Jules Hirsch and others have deomonstrated this in humans, showing that neither eating less nor exercising more will lead to long-term weight loss, as the body naturally compensates." p299
Somewhere, somehow, he stopped being a scientist and started a career as parrot.
"The dissociation of the science of fat metabolism from any discussion of the cause or treatment of obesity was particularly conspicuous throughout this era and could be considered its legacy. When Bray, Van Itallie, Cahill, and Hirsch gave review talks at these conferences, as they did through out this period, they would raise the issue of carbohydrate-restricted diets only to refute the claims that such diets offered a metabolic advantage over low-calorie diets. They would omit any mention of research that might explain the reported efficacy of the diets, even when that research was discussed at the same conferences and by investigators they knew personally." p 420 (in re obesity research in the 1970s)