#1 Landmark study on the effects of dieting

This #1 landmark study on the effects of dieting dates back to 1944/45, a post-war period when much of the world had a limited food supply and many countries still had food rationing

In reading this, I think you might recognize yourself or the behaviors of others.  I must stress this was just ONE diet, imagine the effects of the chronic dieter or the figure/bikini/fitness/physique competitor.


A brutal experiment was conducted, from 19 November 1944 to 20 December 1945, in which 36 men were “starved” for months and observed carefully throughout. The results of this experiment – which can never be repeated – speak volumes about our human behavior, our bodies and our relationship with food.

The men were all conscientious objectors who volunteered for the experiment which was carried out in Minnesota. (Even at the time, what became known as the Minnesota semi-starvation study was thought by many to be unethical.) The full results were only made public in 1950, it a two-volume tome consisting of 1,385 pages.

However, hard facts were well-known by 1946 when the US was already helping millions around the world recover from starvation. In essence, the results contradict all the baloney about diets that has been forced on an unsuspecting public during the decades since that global upheaval.

Although the Minnesota semi-starvation study was intended for a grand and meaningful purpose, it is instructive in today’s world, at least to anyone who has struggled not just with involuntary starvation but with the pressure to attain a certain physical look.

The Minnesota study was not about showing that starvation is bad for you – everyone, from the cavemen on, knew that – but about precisely how we relate to food, both mentally and physically. For anyone who has ever been on a diet or been around somebody on a diet I believe much of the following will hit home.

We all know that we cannot fully rely on studies, especially studies over 70 years old, yet this is that rarity; research which stands the test of time.

In the Minnesota study, run by Prof. Ancel Keyes, the 36 men of healthy mind and body spent the first three months eating normally, while their behavior, personality and eating patterns were noted in great detail. This was followed by six months during which the men were restricted to approximately half of their daily intake, which was about 1500 calories (a pretty conservative intake by today’s standards). During the six months, the men lost about 25% of their body weight.

This was followed by three months of revocation, during which various rehabilitative diets were tried to re-nourish the volunteers. A number of the volunteers continued to be studied for almost nine months following the six months of restrictions.

The men experienced dramatic changes which, in many cases, lasted well into the rehabilitation phase. (When contemplating this, it might be instructive to consider your own behavior and the behavior of others while on a diet, bearing in mind that these were healthy men without a history of restriction. We can shudder while thinking of the cumulative effects on those who do one diet after another)

There was a dramatic increase in the men’s interest in food. They thought about food continually and dreamt about food. They talked non-stop about food. They read about food. They collected cookbooks and stared at photographs of food. This increased interest correlated with a decline in the interest in all other activities and aspects of life.

The men toyed with the food they smuggled out of the dining room to eat alone when, in long, drawn-out rituals, they would make meals last two hours; these were meals that should have taken minutes. They studied food production processes, and they researched menus. They grew interested in nutrition and even in agriculture. They gained pleasure from watching other people eat, and some of the men began collecting food paraphernalia like kitchen utensils and plates. They started by hoarding these items, and then they just began hoarding in general; this included purchases that were completely meaningless.  Following the study, this behavior totally puzzled the men involved/

When asked about what they would do after the experiment 40% of the men said that cooking was one of their future plans. Interestingly, after the study, a few of the men did indeed become chefs or went on to work in agriculture.

They started to drink a lot of coffee and tea, which got out of hand and had to be limited to nine cups a day. Chewing gum also got out of hand, with one man chewing through 40 packs of gum a day.

Not surprisingly, all of the men experienced hunger. Some did okay with this, and yet some experienced a total loss of control. Many of the men binged.  One man working in a grocery store completely lost it and binged on cookies and popcorn, and developed severe self-loathing. Another man had to leave the study as he would eat an enormous amount of food, become sick, go back to eating an enormous amount of food, become sick and just go through the cycle endlessly.

Most of the men could not control their appetite. During the three months of rehabilitation, many basically ate continuously. Even after the three months of refeeding some men still felt hungry after a meal. The refeeding phase was not paltry; it was not uncommon for the men to be eating 8 to 10,000 calories a day.

What is clear from all this is the regulatory systems – which have since been more fully discovered and defined – that govern hunger and fullness, were obviously thrown into disarray by the six months of restriction. Steady eating habits keep the body and mind happy. Punishing diets are just maddening, albeit less maddening if they are less punishing; but the regulatory systems are still going doolally to some extent.

Men would eat until they were bursting. Some had to separate themselves from food altogether as they felt they had no control whatsoever. Those who had happily eaten three meals a day now ate six. And some ate until they could no longer swallow.

It took more than eight months after the refeeding phase of the study for most of the men to return to normal eating patterns. Remember: the 36 men were selected because they were both physically and psychologically healthy.

Most experienced great emotional distress during the study. At least 20% of the men suffered such emotional distress that they were not able to function properly. Many suffered extreme depression, some experienced extreme mood swings with extreme highs and extreme lows. Symptoms include irritability, anger, negativity, argumentativeness, nail-biting, smoking and neglect when it came to personal hygiene.

After two weeks of refeeding, this is one man’s report: “I have been more depressed than ever in my life…. I thought that there was only one thing that would pull me out of the doldrums, that is re¬lease from C.P.S. [the experiment] I decided to get rid of some fingers. Ten days ago, I jacked up my car and let the car fall on these fingers…. It was premeditated.”

This man did indeed cut off three of his fingers. Another man suffered such extreme personality disturbances that he had to leave the study in week ten. And he had only lost ten pounds of his original body weight.

The men became withdrawn and isolated. They lost their sense of humor. They lost the sense of friendship with each other and felt increasingly inadequate. They became less interested in women and those with relationships found them very strained. One man reported it was just too much trouble to see his girlfriend. And if they went to see a show the most interesting part for him was always when there were scenes of people eating.

The men’s interest in sex plummeted, with one man stating he had ”no more sexual feeling than a sick oyster”. You might think that this interest would be the first to return after the experiment, yet even after three months, the men judged themselves to be far from normal in this area.

The men reported difficulty in concentrating, in alertness and comprehension. They experienced intestinal discomfort, less need for sleep, headaches, and sensitivity to noise and light. They reported the loss of physical strength as well as bloating and water retention, hair loss, vision problems and intolerance to cold temperatures.

BMR stands for basal metabolic rate, and this is the amount of energy calories the body needs at rest. We want our BMR to be high as this means we are using a lot of energy. In the Minnesota semi-starvation study, the men’s BMR’s dropped by about 40%, showing their bodies had adapted to the restricted calories. Interestingly during the refeeding phase, those men who gradually increased their calorific intake had no BMR increase for three weeks, whereas those men who ate large amounts of food asap increased their metabolic rate.

I am sure that some readers can relate very personally to (hopefully much less extreme!) versions of what these men experienced. Having spent 13 years of my life competing, and dieting for maybe half of that time, I can certainly relate to it. As I scroll through social media how many times do I see a photograph of somebody’s meal? As a trainer, how many clients have brought me food that they would never eat themselves? As we restrict our food, our fascination with it increases and becomes obsessional.

I watch fitness competitors isolate themselves before an upcoming show, unable to deal with anything other than meal prep and the next workout. I see many of them desperately unhappy; I see how they became intolerant to certain foods and used the word “bloat” many times in every conversation.

Post diet, many suffer a huge rebound in weight which does not help with their depressed state. The real sadness is that this is expected and accepted, and before the body has even had the chance to recover they embark on the next diet.

The Minnesota semi-starvation study was 36 healthy men without a history of food restriction. It is a study that is very unlikely ever to be repeated. We can only surmise about what occurs with years or decades of repeated diets.

The body and the mind have an incredible capacity to adapt to energy deprivation, and when we lose weight the body doesn’t automatically stay at this low weight. Regulatory systems have a bias for weight gain and, as the study shows, the mind and body work against rapid weight loss.

To conclude the men’s journey: following the experiment, the men regained the weight they had lost plus, on average, another 10%. Over the following six months they slowly returned to their original body weight.

Watch this video where I discuss this #1 landmark study on the effect of dieting.

If you like this blog PLEASE share x