The 37-year-old golfer – who struggled with chronic back issues after becoming World Number 1 in 2015 – wishes he had taken better care of himself and not “fiddled around” with his weight and fitness so much in the past.
He reflected to Today’s Golfer magazine: “I wish I would have taken care of myself a little more.
“Looking back, if I was giving advice to someone else, I would tell them; don’t go overboard with the fitness stuff.
“There was a good time there, in ’15 and ’16, where I was in the perfect spot with my body.
“And then I went too far with it, lost too much weight, and then lost 30 yards from my driver.
“And then I went the other way, because I went from 175 pounds to 210 pounds, so there was a dramatic difference in the way my training schedule was and what I ate.
“I wish I hadn’t fiddled around with that so much, because with that came injuries.”
Jason’s back issues have meant he has had to “rework” his playing.
He said: “I would say, in 2015, I was probably at my peak fitness…
“I would look at it now and say I probably don’t hit it as far. My iron play needs to improve.
“My short game is probably still there, but my putting is a lot streakier now.
“Sometimes it gets off and that’s because I physically can’t stand there and putt for two hours any more.
“A lot of limitations that I have are due to my body, so I’ve got to rework it and challenge myself to come at it from a different direction, because the stuff that I used to do that got me to number one in the world, I physically can’t do anymore.
“That’s the reality. I’ve got to somehow come up with different ideas and evolve my game in different ways, so that I can be as successful as I possibly can.”