The Starvation Experiment: How a group of men taught the world a truly horrifying lesson.

Content warning: This post contains images and details of starvation some readers may find triggering.

In early 1944, with WWII grinding on, a call went out for healthy young American men who were willing to starve themselves.

The men asked to volunteer were all conscientious objectors. They had refused to fight in the war, but plenty of them were willing to suffer to help others. Hundreds put themselves forward to take part in the experiment, which was aimed at finding the most effective ways to help starving people once the war was over. Marshall Sutton, a Quaker, was one of them.

“I wanted to do something that had a little more punch to it,” Sutton said in 2014. “I wanted to risk my life in some way and be of service.”

Thirty-six men were chosen for the experiment, which was led by physiologist Ancel Keys at the University of Minnesota. For the first three months, they were given a normal diet, including bacon, eggs, roast beef, mashed potatoes and chocolate sundaes, totalling 3200 calories a day. Then, for the next six months, their diet was cut to a semi-starvation level of 1560 calories a day. Their meals were bland, mostly bread and vegetables such as potatoes, turnips and cabbage.

The changes in the men were dramatic. For starters, they became obsessed with food, thinking and talking about it endlessly. They lingered over their meals – playing with their food, mixing it together in strange combinations, or holding mouthfuls for a long time before swallowing. Some collected recipes.

“Stayed up until 5 am last night studying cookbooks,” one volunteer wrote.

To feel full, they would smoke, drink massive amounts of water or endless cups of coffee, or chew gum – one man getting through 40 packs of gum a day.

The men had to keep active and walk 35km a week. But they lacked energy and withdrew into themselves, preferring to watch movies alone rather than socialise.

“They were men who postponed their living, while they endured their awful present,” wrote Keys and his fellow researchers.

They lost their sense of humour. They suffered mood swings. Sutton said his sexual desires disappeared and he became irritated easily.

"I had a very close friend there and often I’d speak sharply to him and I'd find myself going to him almost every night and apologising,” he added.

The men’s hair started falling out. They felt the cold, and they found it uncomfortable to sit on hard seats. Their pulse rates dropped. There was one plus side: their hearing improved.

A young volunteer called Franklin Watkins started having dreams where he was a cannibal, eating the flesh of an old man.

He made trips into town, gorging on sundaes and milkshakes. When Keys confronted him about cheating on the diet, Watkins threatened to kill both of them. He was sent to a psychiatric ward, but after eating normally for a few days, he recovered and was released.

Meanwhile, another volunteer, Samuel Legg, cut off three of his own fingers with an axe while chopping wood. He later admitted to being “crazy mixed-up” at the time.

"I am not ready to say I did it on purpose,” he said. “I am not ready to say I didn't.”

You can see more image from the experiment in the gallery below (content warning - graphic images)...

Over the six months, the men lost around 25 per cent of their body weight, ending up weighing an average of 52kg. But strangely, they never saw themselves as skinny – they just saw other people as fat.

When the starvation phase was over, the volunteers needed to eat around 4000 calories a day to begin putting their weight back on. Some, who were allowed to eat as much as they liked, consumed more than 11,000 calories in a day. Some reported never feeling full, even when they ate almost non-stop. At least one had to go to hospital to have his stomach pumped due to over-eating.

Fortunately, the mental and physical effects of the experiment were only temporary.

Many of the men went on to humanitarian work. Sutton became an aid worker in the Gaza Strip.

“It made me sensitive to people who didn’t have enough food,” he said of the experiment.

Another volunteer, Henry Scholberg, worked for the United Nations, while another, Max Kampelman, was a diplomat under presidents Carter and Reagan.

At a 50-year anniversary reunion of the group, none of the men were overweight, but several admitted they carried a chocolate bar with them at all times.

LISTEN: Australian Singer/Songwriter Kasey Chambers speaks candidly to Mia Freedman about her battle with an eating disorder.

Looking back today, what’s most interesting about the experiment is what it reveals about the effects of semi-starvation. It’s clear that restricting eating for an extended period changes people’s behaviour and has an impact on their mood.

As US dietitian Katy Harvey points out, this means that some of the personality changes that people link to eating disorders could simply be due to lack of food.

“Remember, these were otherwise healthy men with no eating disorders, so the physical and psychological effects were due to the caloric restriction,” Harvey writes. “What was really fascinating was how many of the men’s behaviours started to mimic eating disorders.”

Kelsey Miller, of The Anti-Diet Project, has picked up on one particular finding of Keys: that the men “postponed their living”. That’s familiar to so many women, that experience of putting something off until they’ve lost weight.

“But what this study indicates is that it might not simply be our desire to wait for a thinner body to start dating, take that trip, or pursue a career goal,” Miller writes. “It may also be the hunger itself keeping us at home, alone and waiting.”

If you or someone you know is struggling with an eating disorder, please seek professional help or contact The Butterfly Foundation on 1800 33 4673. If you are in immediate danger, call 000.

LISTEN: You can hear the full interview with Kasey Chambers below...