Ever wonder how celebrities do it -- keep up their busy work schedules, appear at all the latest, greatest parties and red carpet events, promote their personal causes and charity endeavors, and not lose all their marbles? Seems diet and exercise have something to do with it. Here, four stars weigh in on their high-energy tricks.

• Whoopi Goldberg stays energized by making healthy food and taking it wherever she goes to minimize temptation. While eating at someone else's house, she asks for very small portions. Good idea -- eating too much always weighs me down and makes me feel sluggish.
  
• Daniel Craig keeps up his strength by going to the gym every night when shooting Bond movies. He does as many of his own stunts too. His reward once shooting is over: Lying on a chaise lounge. Hey, relaxation is part of the whole feel-good package, right?
  
• Eva Mendes stays on top of things by running and keeping white flour and sugar out of her diet. It helps her feel better about herself.
• Gerard Butler just likes a good challenge. Give him one and he's invigorated.

  Stars who stay energized(click thumbnails to view gallery)