 Minnesota <unk> Experiment : To study the effects of diet and <unk> , Dr. <unk> Keys of the University of Minnesota Laboratory of <unk> Hygiene placed 32 conscientious objectors on a controlled diet . For three months they were given a normal 3 @,@ 200 calories ( 13 @,@ 000 <unk> ) diet . This was followed by six months of an 1 @,@ 800 calories ( 7 @,@ 500 <unk> ) diet , fewer calories than provided by the famine diet experienced by the civilian population in wartime Europe . The research documented the men 's ability to maintain physical output and the psychological effects such as <unk> , <unk> , <unk> and severe depression . The study then followed the men 's long recovery as they returned to a normal diet and regained the weight lost during the experimentation . 
