This is a story about a study that was done at the end of WWII for the psychological and physical effects of semi-starvation.
It was done on what we might call a low fat and low calorie diet today and it is interesting to read the results of these tests that were done around the middle of the last century. The kind of diet they were on led to ill effects not just on their bodies but on their minds too.
This article compares what they did with the advice that is given today about losing weight and whether long term weight loss is really sustainable.
TOWARD the end of the Second World War, researchers at the University of Minnesota began a legendary experiment on the psychology and physiology of human starvation — and, thus, on hunger. The subjects were 36 conscientious objectors, some lean, some not. For 24 weeks, these men were semi-starved, fed not quite 1,600 calories a day of foods chosen to represent the fare of European famine areas: “whole-wheat bread, potatoes, cereals and considerable amounts of turnips and cabbage” with “token amounts” of meat and dairy.
As diets go, it was what nutritionists today would consider a low-calorie, and very low-fat diet, with only 17 percent of calories coming from fat.
What happened to these men is a lesson in our ability to deal with caloric deprivation, which means, as well, a lesson in any expectations we might have about most current weight-loss advice, and perhaps particularly the kind that begins with “eat less” and “restrict fat.”
The men lost an average of a pound of body fat a week over the first 12 weeks, but averaged only a quarter-pound per week over the next 12, despite the continued deprivation. And this was not their only physiological reaction. Their extremities swelled; their hair fell out; wounds healed slowly. They felt continually cold; their metabolism slowed.
More troubling were the psychological effects. The men became depressed, lethargic and irritable. They threw tantrums. They lost their libido. They thought obsessively about food, day and night.
When the period of imposed starvation ended, the subjects were allowed to “refeed.” At first they were allowed to eat more calories, but restricted as to how much. A subset under continued observation was then allowed to eat to satiety, which was surprisingly hard to achieve. The men consumed prodigious amounts of food, up to 10,000 calories a day. They regained weight and fat with remarkable rapidity. After 20 weeks of recovery, they averaged 50 percent more body fat than they had when it began — “post-starvation obesity,” the researchers called it.
Implicit in many discussions of how best to lose weight is the assumption that hunger, which is a consequence of caloric deprivation, is not an issue. Health and government organizations tell the obese and overweight, who now make up just over two-thirds of our adult population, to do what the study’s subjects did: Eat less, cut back on calories.
That advice implies that the ensuing hunger will be an easily bearable burden (no depression, lethargy, irritability — no tantrums, please!). And bearable not just for 24 weeks, but a lifetime. The Minnesota experiment tells us that when semi-starvation ends, the refeeding period will not end well.
That humans or any other organism will lose weight if starved sufficiently has never been news. The trick, if such a thing exists, is finding a way to do it without hunger so weight loss can be sustained indefinitely. A selling point for carbohydrate-restricted diets has always been that you can eat to satiety; counting calories is unnecessary, so long as carbohydrates are mostly avoided.
But this advice raises a pair of obvious questions, or at least it should: If people on low-carb diets eat less (the conventional explanation for any loss of fat that ensues), why aren’t they hungry? Where’s the semi-starvation neurosis? And if they don’t eat less, why do they lose weight? It implies a mechanism of weight loss other than caloric deprivation and suggests that the carbohydrates and fats consumed make a difference.
Questions like these about the relationship between calories, macronutrients and hunger have haunted nutrition and obesity research since the late 1940s. But rarely are they asked. We believe so implicitly in the rationale of eat less, move more, that we (at least those of us who are lean) will implicitly fault the obese for their failures to sustain a calorie-restricted regimen, without ever apparently asking ourselves whether we could sustain it either. I have a colleague who spent his research career studying hunger. Asking people to eat less, he says, is like asking them to breathe less. It sounds reasonable, so long as you don’t expect them to keep it up for long.