Thomas Doubleday’s Diet Theory The rate of population increase will be less when the quantity of food supply is greater The increase in population and food supply are inversely related

2. Thomas Doubleday
 English Politician
 Author
 Economist
 Social philosopher
February 1790 – 18 December 1870

3. Thomas Doubleday’s Diet Theory
The increase in population and food supply are inversely related
The rate of population increase will be less when the quantity of
food supply is greater

4. The two states of food supply:
1. The Plethoric state having good food supply
where the fertility is low.
2. The De-plethoric state in which due to food
shortage we find diminution of proper
nourishment where the fertility is high.

5. Doubleday divides society into three groups:
1. People who are in a state of prosperity and are well supplied
with luxuries. – The number decreases.
(engaged in mental or physical activities and are living busy life)
2. People who have less supply of food. - The number rapidly
increases.
3. People who fall under the average income group and well
supplied with good food. - Their number is stationary.
(do not overwork and yet are not idle)

6. Non-vegetarian have less capacity to produce. – In Pastoral countries
density of population is low.
Vegetarian and Non-vegetarian have higher capacity to produce.
Pure vegetarian have the highest capacity to produce.

7. The Diet Principle
Poverty stimulates population growth, as the diet of the poor is insufficient.
For instance, Chinese; the Irish and the Scotch were highly fertile because
their diet was inadequate
On the other hand the birth rates in France were low because the French
were well-fed.
Human World

8.  “Whenever a species or genus is endangered in the wake of lack of food, a
corresponding effort is invariably made by nature for its preservation and
continuance by an increase of fecundity or fertility”.
 Ex: rabbits and swine's "will not conceive if fed to a certain height of fatness."
Animal World
The Diet Principle

9. Plant World
The sterility in plant life is possible when the application of
fertilizers is excessive.
The Diet Principle

10. Criticisms
 No scientific basis
 Even in Plethoric state the population goes on increasing and vice versa.
 “The rich people have less children whereas the poor have more,” but in reality???
 “Average income group remains stationary”, but in reality in can increase.
 “Fertility depends on fatness” , but in reality every rich person may not be always fat.

11. “The rich produce fewer children as the fertility would be less amongst
them and therefore, the transfer of their wealth will be distributed
among a few People. Over a period of time, it may happen that there is
no one as an heir to that property and therefore this wealth will pass to
the children of the poor. Again, when the children become rich, they will
restrict their families and their wealth will be gained once again by the
poor. Thus, socialism comes on its own through the automatic
distribution of wealth by nature.”
Conclusion