Here's how it was described in a 1950's study,
What makes a fat man fat?
People can be divided into two groups according to the way they deal with the excess food when they eat more than they require for their daily expenditure of energy.
In 1950 at the Royal Society of Medicine in London, Professor Sir Charles Dodds, who is in charge of the Courtauld Institute of Biochemistry at the Middlesex Hospital, described an experiment he had carried out.
He took people whose weights had been constant for many years and persuaded them to eat double or treble their normal amount of food. They did not put on weight.
He showed that this was not due to a failure to digest or assimilate the extra food and suggested that they responded to over-eating by increasing their metabolic rate (rate of food using) and thus burned up the extra calories.
He then over-fed people whose weights had not remained constant in the past and found that they showed no increase in metabolism but became fat.
So two people of the same size, doing the same work and eating the same food will react quite differently when they overeat. One will stay the same weight and the other will gain.
We all know that this is true even without scientific proof and yet the fact has not been taken into account or explained by any of the experts who write popular books and articles about slimming.
They write as though fat people and thin people deal with food in the same way. Here is the medical correspondent of The Times (11th March, 1957) On the subject:
" It is no use saying as so many women do 'But I eat practically nothing.' The only answer to this is: No matter how little you imagine you eat, if you wish to lose weight you must eat less.' Your reserves of fat are then called on to provide the necessary energy—and you lose weight."
The doctor who wrote these rather heartless words may fairly he taken as representative of medical opinion to-day. He is applying the teachings of William Wadd, Surgeon Extraordinary to the Prince Regent, who in 1829 attributed obesity to "an over-indulgence at the table" and gave, as the first principle of treatment, "taking food that has little nutrition in it."