Recently, the New York Times published a sobering story on the alumni of the 2009 season of The Biggest Loser. A study had shown that almost all of those who had publicly lost hundreds of pounds on the show’s punishing diet and exercise regime had gained nearly all of it back, unless they made staying slim the focus of every waking moment. Their resting metabolism, it turned out, had been broken down to a murmur by the weight loss. We’ve long known that the body doesn’t want to lose weight, to give up its “stubborn” extra pounds—but the study showed that it puts up much more of a fight than anyone thought, refusing to recognize our cultural conviction that skinniness is inarguably superior, physically and morally. As long as there have been diets, there have been dreams of cheating them with science: a pill that would to reduce the appetite or burn away weight.

In the summer of 1933, three Stanford scientists described an astonishing experiment they had performed that seemed to promise magic. In the Journal of the American Medical Association, they reported on the effects of a chemical called “2,4 Dinitrophenol” or alpha-dinitrophenol (DNP), which sped up the body’s metabolism by an astonishing 30 to 50 percent in all nine of their test subjects, causing them to drop around two pounds a week without a pang of hunger. In the overcrowded, over-promising, and over-leveraged field of diet supplements and slimming snake oils it was something new, and it would prove to be both a miracle and menace. Enterprising drug manufacturers seized on the report and followed its template to concoct their own miracle weight-loss pills. “Redusols,” a typical brand, cost $3 for a 30-day supply (about $55 today), and the company spent thousands of dollars advertising it in newspapers and magazines.

Journalists also seized on the story and spun its implications to improbable ends. TIME magazine described the drug as “a vigorous prod for sluggards and a subtle weapon for murderers.” In an article called the “The Skin Food Skin Game,” on the regulations around diet and beauty products, New Republic editors imagined the “economic revolution” that would follow if the drug were proven safe. The summer of 1933 was a nervous time—FDR had just recently put in place the apparatus of the New Deal—and another market crash might come from anywhere. “Manufacturers of rowing machines and other gymnasium apparatus will find their sales enormously curtailed,” the magazine suggested. “Other anti-fat remedies will perhaps be driven off the market. Certain health resorts will no longer be patronized, and manufacturers of clothing, furniture and other products for the excessively stout will see their patronage dwindle.” A magic bullet could have all kinds of side effects.

DNP had been familiar as an industrial chemical for a long time—it was used in fabric dyes, wood preservatives, photographic film developers, pesticides, and most usefully of all, as an explosive. Its fat-burning capacities had first been noted among French munitions workers during World War I, who absorbed the yellowish, powdery substance through their skin and lungs. It caused them sweat like crazy, and occasionally, they died—several pounds lighter. On a molecular level, DNP is a natural explosive: It blows up the pathways by which cells convert fat and carbohydrates into useful energy and instead generates excess heat, setting tiny internal fires that can raise the body’s temperature to lethal levels. Side effects include cataracts, skin lesions, liver and heart problems, and an eerie yellow tinge to the eyes. Once it hit the market, people bought it by the truckload.

The 1930s were a heyday of self-help and self-reliance, as Americans searched for ways to fortify themselves against the uncertainties of the Depression. Fad diets offered the illusion of control over one’s circumstances: The Hay diet insisted on sorting and separating foods into acid and alkaline groups; the grapefruit or “Hollywood” diet, promoted by California citrus growers, had dieters chasing every meal with a grapefruit or its juice. Greta Garbo’s personal dietician, one Gayelord Hauser, achieved celebrity-diet-guru fame with a regiment relying heavily on brewers’ yeast, wheat germ, and powdered milk. The Depression proved that any positive associations of plumpness with prosperity had vanished for good; even in these leanest of times, a lean body was the ideal.