What should be done if one wants to gain or lose
weight The process of gaining or losing weight can be
explained by comparing your body to your car. Both run
1 fuel, food for your body and gasoline for your car. Both
2 that fuel, first into heat, then
energy, some of 3 is used to do work,
and some emitted as waste. And 4 your
car uses more energy when the engine is racing than when it is idling, 5 does your body use more energy when you are
working hard than 6 you are
resting. For the purpose of this comparison, 7 , there is one significant difference between
them. Your car cannot store fuel by turning it into 8
else; all gasoline not 9 remains as gasoline. But your body stores 10
energy as fat. When the gas tank is 11
empty, the car won’t run; but your body can burn fat to provide
more energy. Therefore, if you want to gain weight, you must do
12 of two things: eat more calories
(units of heat, therefore energy), or use less through
13 . If you want to lose weight, you do the 14 , decrease your intake of calories or increase
the amount of energy you spend. There is 15 way. Gaining or losing weight is always a relation between intake and output
of potential energy.