The process of gaining or losing weight can be explained by comparing your body to your car. Both run (51) fuel, food for your body and gasoline for your car. Both (52) that fuel, first into heat, then energy, some of (53) is used to do work, and some emitted as waste. And (54) your car uses more energy when the engine is racing than when it is idling, (55) does your body use more energy when you are working hard than (56) you are resting.
For the purpose of this comparison, (57) , there is one significant difference between them. Your car cannot store fuel by turning it into (58) else; all gasoline not (59) remains as gasoline. But your body stores (60) energy as fat. When the gas tank is completely empty, the car won’t run; but your body can burn fat to provide more energy.
Losing weight can seem like an unwinnable war. You know you need to eat less and exercise more, but that’s (1) impossible when everything in your life—from job stress to the temptation of fast and (2) foods—encourages you to do the (3) . A healthy diet and regular exercise are certainly the best weapons against weight gain, (4) the fact is that sometimes they aren’t enough. And that’s (5) science may someday be able to help.
In various research labs, researchers are closely looking (6) the biological mechanisms of obesity, (7) why some bodies store fat so (8) , and why others are better at burning the calories they (9) . They are discovering a surprising (10) of metabolic and physiologic factors that contribute to weight: did you know, for instance, that your intestines are full of bacteria that can (11) or restrain weight gain to some extent Or th
A. weapon
B. clue
C. problem
D. key
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