Mickelson decided to take drastic action to fix his recent string of poor performances.
Five-time major champion Phil Mickelson fasted six days and lost 15 pounds during a retreat he took ahead of this year's British Open.
In a video he posted on social media on Sunday, Mickelson said he took a "hard reset" over the last ten days, implementing some drastic changes to fix his poor play of late. Mickelson missed the cut in four of his past six starts since winning the AT&T Pebble Beach National Pro-Am this year.
"Let's get real for a few minutes," Mickelson said. "I haven't posted anything because I haven't felt good about myself and the way I've been playing, and so I haven't done anything or wanted to be in public. The last ten days I've done what I call a hard reset to change and try and make things better."
Mickelson, 49, said he lost 15 pounds after going on a six-day fast that included just water and a special coffee blend for wellness.
"I don't know if it's going to help me play better or not,'' Mickelson said. "But I'm willing to do whatever it takes to try and get my best back.''
The British Open will take place from July 18-21. Mickelson last won the Open Championship at Muirfield in 2013.