According to one study, people eat more when the food is presented in larger plates. Statistics show that the average American plate size is bigger than that of many other countries.
Many restaurants realized that customers feel more satisfied when they believe they got more than what they paid for. As a result, many of these restaurants started offering very large size meals.
Food is cheaper
Food is generally considered cheaper in the US than in many other countries. Because people can easily afford to buy large sized meals, they simply buy them.
Compensate for hard times
Initially, when colonies moved to the US food supply was scarce and many people used to die from bad crop seasons. This could have created a psychological unconscious motivation for the nation to eat more.
As a result of the advanced technology, plenty amounts of food were able to be produced at low prices and as a result people started eating more.
The great depression theory
According to one theory, the great depression, which made buying food harder, might have contributed to the desire to eat more after the depression ended. This desire might have been passed to children. (See How does it feel like to be depressed?)
It’s a part of the culture
Eating is part of the American culture. Americans celebrate many of the important feats and events by eating.
Expectations of large portions
Americans have learned to expect getting large portions for their money. As a result, many restaurants starting providing those customers with what they are looking for.
Tough competition between food sellers
As the competition is tough between food sellers, many of them started increasing the portions they provide in order to become more competitive.
High consumption culture
According to one theory, Americans have a culture of consumption that extends to include many things in addition to food. This could have been one reason why many people learned to consume more food.
Cultural status symbol
Because of the shortage of food supply, early immigrants who suffered from eating more might have been considered a status symbol. Those motives might have been unconsciously passed to new generations.
Salt, fats and sugar addiction
Salt, fats and sugar are known for their addictive nature. Because many American foods include fats, sugar or salt, people might get motivated to eat more. (See Why salt is bad for your health?)
Why many Americans eat big portions?
Why Americans Eat An Insane Amount Of Food? Why many Americans eat big portions?