How much weight did George Clooney gain or lose for his role in Gravity?

 George Clooney did not have to gain or lose any weight for his role in the movie "Gravity." The weightlessness of space, which is a major theme in the movie, was created using special effects and filming techniques, rather than by altering the weight of the actors.

Instead, Clooney and his co-star Sandra Bullock underwent extensive training to prepare for their roles, including spending time in a zero-gravity simulator and practicing scuba diving to simulate the experience of weightlessness.

While Clooney is known to have transformed his body for other roles, such as gaining weight for his role in "Syriana" and losing weight for his role in "The American," there is no evidence that he did so for "Gravity."