The Minnesota Starvation Experiment

It is one of the oldest scientific experiments on starvation (1/2 calories). Some amazing results that echo so many failed diets!

In 1944, Two hundred conscientious objectors volunteered, as an alternative to war, and Keys and his team of researchers whittled these down to 36 men. The men (all aged 20-33) were chosen for their physical and mental resilience. The results, 1,385 pages in total, were published in “The Biology of Human Starvation” (1950).

The year long experiment was split into four phases:
1) The Control Period (12 weeks): The key goal of this period was to determine the calorie requirement for the men. It was established that the men maintained their weight at approximately 3,210 calories a day whilst walking 22 miles each week – an average of just three miles a day (45-60 minutes walking).

2) The Starvation Period (24 weeks): The fact that the study was referred to as a “starvation experiment” is so interesting, because the six-month ‘starvation’ was actually a calorie controlled diet of approximately 1,600 calories per day (more calories than many modern diets allow). The meals were made up of foods typically available in Europe during the latter stages of the war: potatoes, turnips, bread and macaroni – i.e. starchy carbohydrates. Ancel Keys set out to try to induce a 25% weight loss in each man in 24 weeks.

3) Restricted Rehabilitation Period (12 weeks): The men were divided into four groups of eight (four had been dismissed for stealing food and binging) and given different calorie, protein and vitamin levels to see what would best re-nourish them back to health.

4) Unrestricted Rehabilitation Period (8 weeks): For the final period, the men could eat as much as they wanted and the research team carefully recorded what they did in fact eat.

This invaluable study tells us the following about dieting and weight loss:

1) Physically, the men reported incessant hunger, weakness, exhaustion and they lost 21% of their strength in the first 12 weeks alone. They experienced dizziness, muscle wasting, hair loss and reduced coordination. Several withdrew from their university classes, because they simply didn’t have the energy or motivation to attend.

2) You may have heard of the saying “To lose 1lb of fat you need to create a deficit of 3,500 calories.” The Minnesota experiment alone renders this statement invalid.

The deficit, in Keys’ study, started off at 1,640 calories a day. Assuming that the deficit remained at 1,640 for the 24 week ‘starvation’ period, if the 3,500 formula were correct, during the 24 weeks, every man should have lost at least 78 pounds in fat alone and more on top of this in water and lean tissue. The average weight loss of the men was less than half of this – 37 pounds – 1.5 pounds per week. If the 3,500 formula were correct, the lightest man in the study, Bob Villwock from Ohio, should have finished the study below three stone (he would, of course, have died long before this).

3) The less you eat, the less you must continue to eat to have any chance of losing more weight and weight loss will stop, at some point, whether you like it or not.

As Keys showed, the men needed 3,200 calories, on average, to maintain their weight. As the men were given 1,570 calories a day in the ‘starvation period’, they lost weight and their energy need fell and therefore the calorie level needed to fall, to maintain the deficit.

Interestingly, Keys rejected the 3,500 formula from the outset and relied instead on adjusting the calorie intake every week to try to induce his desired weight loss of 25%. Keys found he needed to limit some men to 1,000 calories a day to try to induce further weight loss (the men should have been losing over 5lbs per week, at this calorie intake, having created a deficit of almost 2,500 calories a day from their original calorie need. In reality the body had adjusted energy need to resist any further weight loss).

All reached a plateau around week 20 and further weight loss could not be induced. At least one diary recorded weight gain in the final month of the ‘starvation’ period.

4) The body will do whatever it takes to reverse the effects of starvation/dieting.

During the restricted rehabilitation period, the four different groups of men were given 400, 800, 1,200 or 1,600 additional calories per day. Within each group of eight men, some were also given additional vitamin and protein supplements. Ancel Keys concluded that the only thing that determined the speed at which the men recovered was the calorie intake. The body didn’t respond to vitamins or protein – it just wanted the energy (calorie) deficit to be reversed.

It can be no surprise; therefore, that when given free access to food, in the final two months, the men overate and binged to correct the calorie deficit they had suffered. One man managed to eat 11,500 calories in one day and men still felt hungry consuming twice the number of calories that maintained their weight in the control period. They all gained all their weight back and approximately 10% more than they weighed before the experiment. Men who had previously shown no awareness of body size and image reported ‘feeling fat’.

http://www.zoeharcombe.com/2009/12/the-minnesota-starvation-experiment/