A landmark starvation study from World War II sends an important message for today’s low-calorie dieters: Going hungry is not a winning strategy.
Let me share with you the scariest story I know, one that rivals any told at night around a campfire. It starts off sort of unbearably — with famine.
For hundreds of thousands of years, humans have endured various periods of famine. In modern times, none was as severe as during World War II. Naval warfare effectively ended commercial fishing, and in continental Europe, the German army often starved a city as a way of capturing it. During the 872-day siege of Leningrad, for example, starving Russians were forced to eat zoo animals, pets, and even wallpaper paste and leather. By the time the city was freed, nearly 1 million people had died.
Meanwhile, in the United States, Army officials began researching the nature of starvation. They knew their soldiers had been malnourished in enemy POW camps, and they wanted to learn how to rehabilitate them when they were freed. Were there psychological effects to malnutrition, they wondered, or simply physiological ones? To find the answers, they hired a University of Minnesota scientist named Ancel Keys.
Keys (who passed away in 2004, two months before his 101st birthday), designed a one-year study involving 36 healthy volunteers. Called the Minnesota Starvation Experiment, the study’s volunteers were conscientious objectors (COs) to the war. Getting COs to volunteer to go hungry wasn’t a problem: Initially, 200 signed up through Civilian Public Service, a nonpaid government program that provided alternatives to serving in battle for COs. The 36 who were ultimately selected as study subjects would be fed a diet meant to mimic that of occupied Europe: meager, barely life-sustaining meals (with the exception of all the water and black coffee they could drink, and an unlimited supply of chewing gum and cigarettes).
The study was divided into three parts: For the first three months, the men ate three hearty meals per day, totaling roughly 3,200 calories. During the second part of the study, lasting six months, food was rationed to two calorie-restrictive meals per day; study participants were then monitored for three months for effects. Only three months into the six-month starvation-phase of the meal plan, the participants just about went crazy.
How crazy? Two ended up being hospitalized in psych wards. In order to get out of the study, one cut off his fingers with an ax while on a supervised visit to a friend’s house. Two others chewed so much gum (as many as 40 packs a day each) that their mouths bled. One started compulsively digging food out of garbage cans and lying about it. Another began hoarding photos of food from magazines.
Keys gave his starving subjects psychological tests throughout the experiment and found, within only a few weeks on the starvation plan, that the healthy young men had become neurotic and psychotic. They’d lost their ambition, self-discipline and mental alertness, along with their ability to focus and comprehend. Their energy levels had been drained.
Now, here’s the scariest part of all: This “starvation” diet, the one that sparked psychosis and mutilation among these starving study participants, allowed an average of 1,570 calories.
That’s right, a little more than 1,500 calories. Anyone who has followed any sort of popular, mainstream diet in the last few decades knows that 1,500 calories is often prescribed as an average calorie limit. Several registered dietitians are still suggesting even less, a 1,200-calorie-a-day diet.
Check out any bookstore: There’s The 1,500-Calorie-a-Day-Cookbook, The 1,200-Calorie-a-Day Menu Cookbook, 400 Calorie Dinners, and Hungry Girl 200 Under 200: 200 Recipes Under 200 Calories. You bet that girl is a hungry girl.
If you’re a chronic dieter, or worse, you feel like a failure because you’ve been unable to stick to diets like these, I humbly suggest you leave all those number-calorie books on the shelf and check out Todd Tucker’s book, The Great Starvation Experiment: The Heroic Men Who Starved So That Millions Could Live (Free Press, 2006).
Tucker’s account of Keys’s World War II experiment was written without any thought about diet, weight loss or any other contemporary issue, but it will likely change the way you think about diet-chatter forever.
Tucker shares the alarming outcomes of Keys’s study: In three months of eating a 1,500-calorie diet, the men each lost an average of 24 percent of their body weight — roughly 40 pounds. But they also lost, on average, one-third of a centimeter in height and 500 cubic centimeters of blood; the size of their hearts shrank by an average of 17 percent, and their resting heart rate slowed to as few as 30 beats a minute.
In response to a diet that gave them only half of the calories they craved, the men constantly complained of being cold. They became increasingly irritable and impatient. Rather than repressing thoughts about food, they became obsessed with the idea of eating, compulsively collecting recipes and studying cookbooks.
When they were restored to a “normal” diet during the last three months of the study (“rehabilitation,” as Keys named it on his report), they gained fat back first. They reported feeling hungry no matter what they ate, even though some ate as many as 5,000 calories a day (one participant consumed 11,500 calories a day but still admitted a lack of satiety).
Some suddenly displayed body-image issues for the first time, reportedly feeling fat, while still thinking about nothing but food. Months later, the 32 men who made it to phase three weighed, on average, far more than they had before the study — about an extra 27 pounds apiece!
We’d call that “yo-yo” dieting today, and maybe blame the subject’s negative results on a “lack of willpower.” But when Ancel Keys analyzed his study subjects, he concluded that these effects were simply that of human physiology: If you feed someone 1,500 calories a day, his mental health will be jeopardized; he’ll exhibit strange, obsessive behaviors; and he’ll end up fatter than he was before he started. It’s just science.
Those findings from nearly 70 years ago fly in the face of today’s calories-in, calories-out diet culture. But anyone trying to lose weight and keep it off would do well to heed the lessons of this cautionary tale. Because while the human body is, as Tucker notes, “supremely well equipped” to survive a period of starvation, it’s not able to do so without some very undesirable consequences for metabolism, body composition and, perhaps especially, mental well-being.
“After a year [in Keys’s study], none of the men had been forced to quit because of their bodies giving out,” writes Tucker. “It was the mind, in the end, that surrendered first.”
So what’s a thoughtful person who wants to lose weight to do? Give your body an abundance of nutritious foods, and get some sort of regular exercise that makes you happy. Don’t buy into severe caloric deprivation, because your mind and your body require energy that food and movement naturally provide. The alternative can lead you down a dark and sickly path.
Dara Moskowitz Grumdahl is a James Beard Award–winning food and wine writer.