Tom Arnold has lost about 90 pounds since his first child was born last year, and he was looking quite thin at 2014's SXSW festival (left). He'd actually lost the same amount of weight before but regained it when he didn't maintain healthier habits. After his son was born, he knew he needed to make a lasting change. "I saw that little baby and I thought, 'I gotta stay alive for as long as possible,' " Arnold said in January. "That's a lifelong commitment."