thE proCEss oF gAining or losing wEight CAn BE ExplAinED By CompAring your BoDy to your CAr.Both run {{u}}(56) {{/u}} FuEl, FooD For your BoDy AnD gAsolinE For your CAr.Both {{u}} (57) {{/u}} thAt FuEl, First into hEAt, thEn EnErgy, somE oF {{u}} (58) {{/u}} is usED to Do work, AnD somE EmittED As wAstE.AnD {{u}} (59) {{/u}} your CAr usEs morE EnErgy whEn thE EnginE is rACing thAn whEn it is iDling, {{u}} (60) {{/u}} DoEs your BoDy usE morE EnErgy whEn you ArE working hArD thAn {{u}} (61) {{/u}} you ArE rEsting. For thE purposE oF this CompArison, {{u}} (62) {{/u}}, thErE is onE signiFiCAnt DiFFErEnCE BEtwEEn thEm. your CAr CAnnot storE FuEl By turning it into {{u}} (63) {{/u}} ElsE; All gAsolinE not {{u}} (64) {{/u}} rEmAins As gAsolinE.But your BoDy storEs {{u}} (65) {{/u}} EnErgy As FAt. whEn thE gAs tAnk is {{u}} (66) {{/u}} 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 {{u}} (67) {{/u}} oF two things: EAt morE CAloriEs (units oF hEAt, thErEForE EnErgy), or usE lEss through {{u}} (68) {{/u}}. iF you wAnt to losE wEight, you Do thE {{u}} (69) {{/u}}, DECrEAsE your intAkE oF CAloriEs or inCrEAsE thE Amount oF EnErgy you spEnD、thErE is {{u}} (70) {{/u}} wAy. gAining or losing wEight is AlwAys A rElAtion BEtwEEn intAkE AnD output oF potEntiAl EnErgy.

A．in
B．on
C．For
D．AgAinst