This is not a popular answer, but it's the primary reason I, and many others I know, have gotten into shape and stayed that way for well over a decade: Hate yo

This is not a popular answer, but it's the primary reason I, and many others I know, have gotten into shape and stayed that way for well over a decade: Hate yourself. Be fatphobic. Hold yourself to nearly unattainable standards and consider yourself a failure for not meeting them. Be disgusted by what you see in the mirror. IMPORTANT CAVEAT: Note that I absolutely do not recommend this course of action for anyone prone to depression, but for anyone with normal seratonin chemistry and solid self-esteem elsewhere in their life, this is a mentality that absolutely works for attaining, and maintaining, fitness.