Question

Why do people routinely stuff themselves at all-you-can-eat buffets? Explain in terms of both utility and demand theories.

At any level, the marginal cost of take another bite at an all-you-can-eat place is zero. In terms of utility, a person should therefore consume until the marginal utility from eating is zero, "e.g., stuffed" From a demand point of view, people will consume where their own demand curve crosses the x-axis (0 price)

Answer 1

In order to answer the question, the theory of consumer behavior must be examined.
Utility is the satisfaction or pleasure a consumer gets from the consumption of a good or service (all-you-can-eat buffet) and total utility is the total amount of satisfaction derived from the consumption of a single product or (all-you-can-eat buffet) a combination of products. Marginal utility is the extra utility (satisfaction or pleasure) a consumer obtains from the consumption of one additional unit of a good or service.
The law of diminishing marginal utility states that as the consumer increases the consumption of a good or service (all-you-can-eat buffet), the marginal utility (satisfaction or pleasure) gained from each additional unit of the good or service decreases