The claimWhat Phil actually said
Ahead of the 2019 Open Championship, Mickelson posted a video saying he had spent about ten days on what he called a hard reset, including a six-day fast on water and coffee plus a short retreat, and had lost 15 pounds. He has since talked repeatedly about fasting as part of how he manages weight and recovery.
- foxnews.com: Phil Mickelson in their own words
- Patikorn et al., JAMA Network Open, 2021: umbrella review of meta-analyses of randomized trials found intermittent fasting improved weight and some cardiometabolic markers but was not clearly superior to continuous calorie restriction.
- Lowe et al., JAMA Internal Medicine, 2020: randomized trial of time-restricted eating found minimal weight loss versus a control schedule, with a significant proportion from lean mass.
- Wilhelmi de Toledo et al., PLoS One, 2019: observational series of 1,422 supervised four to 21 day fasts reported weight and blood pressure reductions with few serious adverse events.
Why it mattersWhy this matters for longevity
Prolonged fasting is being copied from athletes by people who have no medical supervision and no reason to lose 15 pounds in a week.
Fast weight loss during a water fast is largely fluid and glycogen, so the number on the scale overstates what actually changed.
Fasting is genuinely unsafe for some people, including those on insulin or blood pressure medication and anyone with a history of disordered eating.
The evidenceWhat the science says
An umbrella review of meta-analyses of randomized trials found intermittent fasting improved body weight and some cardiometabolic markers in adults with overweight or obesity, and a large observational series of supervised four to 21 day fasts reported that most participants completed them without serious adverse events and with improvements in weight and blood pressure.
The same umbrella review found no consistent superiority of fasting over continuous calorie restriction, meaning the benefit tracks with eating less rather than with the fasting schedule itself. A randomized trial of time-restricted eating found only modest weight loss and a substantial share of it coming from lean mass. There is no evidence at all that fasting improves sport-specific performance, and a multi-day water fast is not a self-directed activity.
TakeawayThe honest takeaway
The practical lesson
If your goal is weight loss, a sustainable calorie deficit does the same job as an extreme fast without the supervision requirement.
RelatedRelated habits
Each of these is a habit you can build on its own. Explore them through the Topics index.
SupplementsThe supplement angle: Electrolytes and protein
Support a habit, do not replace one
Extended fasting shifts fluid and electrolyte balance and can cost lean mass. Anyone considering it should discuss monitoring and refeeding with a clinician rather than improvising.
Supplements can support good habits. They do not replace sleep, movement, nutrition, or medical care. Talk with your healthcare provider before starting anything new.
This is educational commentary, not medical advice, and does not imply that Phil Mickelson endorses, is affiliated with, or uses Winning Longevity or any product. We critique the claim and the evidence, not the person. Any direct quote is a placeholder until sourced. Talk with a qualified healthcare provider before changing your routine. See our health disclaimer.
