Between the years of 1932 and 1942, Dr. Francis Pottenger, Jr., M.D., conducted a feeding experiment to determine the effects of heat-processed food on cats under the supervision of Dr. Alvin G. Foord, M.D., Professor of Pathology at the University of Southern California and Pathologist at the Huntington Memorial Hospital in Pasadena. The study lasted for 10 years and was divided into two groups, raw meat group and cooked meat group.

Raw Meat Group

The cats in the raw meat group were fed a diet of 2/3 raw meat, 1/3 raw milk, and cod liver oil. From generation to generation they maintained a regular, healthy, normal body in every way. Tissue tone and fur quality was good and little shedding was noted. The calcium and phosphorus content of their femurs remained consistent and their internal organs showed full development and normal function. Over their life spans, they proved resistant to infections, to fleas, and to various other parasites, and showed no signs of allergies. In general, they were gregarious, friendly, and predictable in their behavior patterns, and when thrown or dropped as much as 6 feet to test their coordination, they always landed on their feet and came back for more play. These cats reproduced one homogeneous generation after another with the average weight of the kittens at birth being 119 grams. Miscarriages were rare and the litter averaged five kittens, with the mother cat nursing her young without difficulty.

Cooked Meat Group

These cats were fed a diet of 2/3 cooked meat, 1/3 raw milk and cod liver oil. Each kitten in a litter was a different size and had a different skeletal pattern. X-rays revealed very obvious evidence of deficiencies. The long bones of these cats tended to increase in length and decrease in diameter. The internal structural mesh of the bones became coarser and showed evidence of less calcium. In the third generation, some of the bones became as soft as rubber and a true condition of osteogenesis imperfecta was present. (Note the similarities of disease as compared with people who eat mostly cooked food.) Cats on the cooked-food diet had heart problems, nearsightedness and farsightedness, under-activity of the thyroid or inflammation of the thyroid gland infections of the kidney, of the liver, of the testes, of the ovaries, and of the bladder arthritis and inflammation of the joints inflammation of the nervous system with paralysis, meningitis, and obesity (except with mother cats who were underweight). They would sneeze, wheeze, and scratch. They were irritable, nervous, and did not purr. All these conditions occurred commonly in these cats fed cooked meat. Infections of the bone appeared regularly and often appeared to be the cause of death. By the time the third deficient generation was born the cats were so physiologically bankrupt that none survived beyond the sixth month of life, thereby terminating the strain.

A study of the microscopic section of the lungs of second and third generation deficient cats showed abnormal respiratory tissues. The lungs showed hyperemia, some edema, and partial atelectasis, while the most deficient showed bronchitis and pneumonitis.

Cats fed cooked meat also abounded with vermin and intestinal parasites. Skin lesions and allergies appeared frequently and were progressively worse from one generation to the next. Pneumonia and emphysema were among the principal causes of death in adult cats, while diarrhea followed by pneumonia took a heavy toll on the kittens. Autopsies presented ovarian atrophy and uterine congestion. Abortion in pregnant females was common, running about 25% in the first deficient generation, to about 70% in the second generation. Deliveries were generally difficult, with many females dying in labor. The average weight of the kittens born was 19 grams less than the raw-meat-nurtured kittens.

Once when a female cat was subjected to a deficient diet for a period of 12 to 18 months, her reproductive efficiency was so reduced that she was never again able to give birth to normal kittens. Even after three or four years of eating an optimum diet, her kittens still showed signs of deficiency in skeletal and dental development. When her kittens were maintained on an optimum diet, a gradual reversal and regeneration took place.

Pasteurized Milk

Cats fed pasteurized milk as the principal item of their diet showed skeletal changes, lessened reproductive efficiency and their kittens presented progressive constitutional and respiratory[10][ problems as was evident in the first, second, and third generation deficient cats eating cooked meat.

Cats fed evaporated milk showed even more damage than their pasteurized counterparts, while the most marked deficiencies occurred among those fed sweetened condensed milk, as they developed much heavier fat deposits and exhibited severe skeletal deformities. They showed extreme irritability and paced back and forth in their pens nervously. The life span of young cats fed metabolized vitamin D milk diet was less than half as compared to the cats above. The metabolized vitamin D milk from cattle fed irradiated yeast was even more damaging to the males

Dr. Pottenger's Guinea Pigs

A group of guinea pigs was initially fed a diet of rolled and cracked grain with supplements of cod liver oil and field-dried alfalfa. Soon, they showed loss of hair, paralysis and high rate of litter mortality. Diarrhea, pneumonia and other deficiency symptoms increased. When fresh cut, green feed (grass cut after sun-down, sacked and delivered before sunrise) was introduced into their diet, the guinea pigs showed remarkable improvement. Infant mortality decreased and the animals became huskier. No new cases of paralysis developed and the alopecia (baldness) lessened, though it did not disappear entirely.

A few guinea pigs with severe diarrhea and loss of hair were allowed to run outside the pens to feed on growing grass and weeds. In less than 30 days, these foraging animals showed even greater improvement than those receiving cut greens inside the pens. Their diarrhea stopped, their hair returned with a soft, shiny, velvety texture they were healed and became well. When they were placed back inside the pens, they showed no further signs of gastrointestinal upset or other ailments.

From these experiments we can conclude that cooked food disrupts the digestive process which: