PHIL MICKELSON is looking remarkably trim lately - a far cry of his former self.

The 51-year old won the PGA Championship at Kiawah island last summer, and captured his sixth major.

"Lefty" was a very portly figure in mid-2000s, as he personally admitted. However, he has made remarkable improvements to his diet.

The American, who had gained a lot of weight over the years, has made great efforts to trim his body.

Mickelson was partly alerted by a 2010 diagnosis of psoriatic arthritis.

He is now fully committed to a six-day fast during which he eats only water and a coffee blend.

This mixture includes Ethiopian Yirgacheffe coffee and almond milk.

After partnering with Dave Phillips, a performance consultant, Mickelson has become an advocate for "Coffee For Wellness".

The golfer, despite being at the top in his game by the mid-2000s began to feel his body and see his performance decline.

He stated that he was not playing well and wasn't feeling good about himself.

"I didn't recover as quickly after the rounds, and I felt tired and not focused towards end of round.

"I felt that getting back that was the first step to getting it back was getting in shape -- getting lighter. And what I've noticed, I've been able to recover faster."

Mickelson also feels the overwhelming benefits of the diet plan, which isn't just about weight loss.

In 2019, he said, "I didn’t fast to lose weight." "I fasted to heal."

Mickelson looks as good as ever on the course, and he acknowledged that such a shift was essential if Mickelson was to ever recover his best form.

He won at Kiawah Island.

Mickelson was selected in the field for the 2022 PGA Championship at Southern Hills, which will be held later this month.

Despite controversy over his support for the rival Saudi Arabian-backed league, he is set to defend his trophy.

Mickelson stated in a Twitter video that he supported the plan last year: "I haven’t felt good about my self and the way that I’ve been playing, so I haven’t done anything or wanted be in public."

"The past 10 days have been a hard reset. It's a chance to change things to make them better.

"I don’t know if it’s going to improve my playing or not, but it’s something I’m willing to do to get my best back."

He also noted that he would continue to make the lifestyle change in 2019

"I will continue to eat better, eat more, exercise more, and stay committed to this goal.

"It won’t be as dramatic or fast, but I would expect that over the next one-to two years I will continue to drop a bit [in weight].

Phillips, a performance consultant, described fasting as a common practice among athletes.

He stated, "It's certainly not as drastic as everyone thinks."

"There are many athletes who do this type of thing in the performance space.

"Fasting is a hard reset that the body does to get rid of the bad stuff, and craves the good stuff.

"The body goes into fight or flight. Sometimes, you have to do this.