Magician Penn Jillette used to weight about 340 lbs. He was happy with his weight and the way he looked. He said he didn't even mind not having a lot of energy. But his blood pressure was dangerously high, and his doctor said he might die before his children grew up. So he changed his eating habits. It's been 17 months since he lost 100 lbs, and in this video he explains how he did it.
Here's Penn in 2013, talking about Donald Trump: