And the 36-year-old American did it by cutting out fast food and sugar.
"I would say a three-year old probably eats better than I used to," Woodland said.
Woodland showcased his slimmer self at this week's PGA Championship as he teed off on Thursday in a marquee group that includes two other reigning major champions, Brooks Koepka and Shane Lowry.
Koepka is a two-time defending PGA champion and Lowry is the reigning British Open champion.
"It's probably something I should have done a long time ago, take care of my body a little bit," Woodland said on Wednesday.
"I'm getting a little older, being out here, hanging around Justin Thomas and all these young guys, I need to take care of myself if I want to be here for a lot longer. I needed to lose some weight.
"I was down just over 27 pounds. I'm down about 20 pounds which I feel is where I want to be right now. I feel better when I get done walking after the round."
He not only feels better about himself, but says a healthier diet will prolong his career
"I want to be out here for a long time, and I needed to change my body to do that," he said.
Woodland has consecutive top-10 finishes at the PGA Championship, tying for eighth at Bethpage Black last year and tying for sixth at Bellerive in 2018.
He said capturing his first major at the US Open just down the road from here in Pebble Beach has helped foster a winning mental attitude.
"I'm definitely a more confident player," Woodland said. "You work so hard and you know you're getting better, but sometimes you need the results to feel that.
"You don't always get them as quickly as you'd like. I know I can contend and I know I can win. That's a huge relief.
"It definitely helps you sleep better at night, and you definitely show up at the golf course in a better mood, knowing you don't have to be perfect today. My stuff is still good enough to win." — AFP