What happens when a person loses body fat?

When a person loses body fat, the person is losing a little of his/her source of insulation, stored energy, and bone support.

Although if one has an excess amount of body fat, it can be deleterious to the health of the person so people tend to try to lose their fat (unless they are trying to become sumo wrestlers, who require a lot of weight).

Losing body also allows the body to be more nimble.

Also losing body fat can have many psychological effects such as heightened self esteem.