By Peter Park



In my previous post, I talked about my 10-month experiment with the ketogenic diet. If you missed that post or need a quick refresher about what “going keto” means, the ketogenic diet is rich in fat, moderate in protein, and super stingy in carbs (50 grams per day or less.) Going keto puts the body into a metabolic state known as ketosis. When you’re in a state of ketosis, the liver produces ketones that become the main energy source for the body. Or in simpler terms, your body becomes a fat burning (as opposed to glycogen or sugar burning) machine. Eat fat, burn fat. There you go.

As I write in that first post, I experimented with going keto because it’s becoming a popular (fad) diet, and a lot of my clients have asked if I recommend it. But I never recommend any new health or fitness fad or concept without trying it out on myself first. So as I’ve often done over the course of my 30-year training career, I became my clients’ guinea pig.

I loved going keto, because the foods I got to eat, tons of eggs, avocados, vegetables cooked in olive oil, cream in my coffee, butter in my anything, moderate amounts of chicken, steak, bacon are just so good and satisfying. I’d eat a big keto breakfast and feel satiated until dinner time. The down side: No fruit (too much sugar), no sweet potatoes, rice, bread, no sugar of any kind.

During long, low-intensity training going keto is perfect. That’s why so many ultra-athletes these days are going keto. But during high-intensity interval or circuit training I’d run out of gas, because my body tried to tap into my glycogen stores. But because I wasn’t eating any carbs, I didn’t have any glycogen stores – or not enough anyway. All my fuel was in my fat tank. So I’d bonk. Most of my regular clients, however, don’t train as intensely as me, so when it comes to performance, going keto just might work for them.

At the start of my 10-month period I had my blood tested and my total cholesterol was 170. I can live with that. But after going keto for 10 months my total cholesterol shot up to 280. That I cannot live with. Why, you might ask, when we now know cholesterol doesn’t cause heart disease? “Not only is cholesterol most likely not going to destroy your health,” says a recent Washington Post article, “but it is also not the cause of heart disease.”

Maybe high cholesterol isn’t bad for everyone’s heart. (Even though cardiologists for the last 40 years have been hammering into our consciousness that it is.) I’ll buy that. But as a long-time trainer who’s worked with a thousand people over the years, the one absolute I know is no two bodies are absolutely the same. (The second absolute: You have to go slow to go fast.) Maybe high cholesterol won’t hurt everyone’s heart. But do I know for sure it won’t hurt mine? And consider this: Even if cholesterol isn’t the bad guy here, dramatically rising cholesterol levels indicate a change – and I have to presume not for the healthier – and the only change I made was going keto. And since one plus one still equals two, these days…

Think I’m a little paranoid? Or a lot? Well, me and my heart? We got us a history. I write about it in more detail in my book “Rebound”, but here’s the skinny (haha): One morning back in 2008, I woke up completely numb on my right side. My wife Kelly (a registered nurse) wanted to take me to the ER, but I had clients to train that AM, so I got in my car and drove to my gym, stopping along the way for a coffee. As usual I ordered it “black with room for cream.” Or tried. The gibberish that came out of my mouth was more like, “scrim lop whop whoop flim-flea shtoof.” The poor cashier probably thought I was speaking in Tongues.

But I made it to my gym. The first clients I trained that morning were all doctors, and they told me same as Kelly, get the hell to the ER. Instead, I went to one of the steepest streets in town, Sea Ranch, and I ran repeats up and down to burn whatever was ailing me right out of me. Till I realized this ain’t working, dude. I finally made my way to the ER.

Turns out I’d suffered a TIA (transient ischemic attack) which occurs when the blood flowing to the brain stops for a short period of time and causes stroke-like symptoms (paralysis and slurred speech.) Doctors determined that the TIA’s cause was a hole in my aorta, and I had open heart surgery to repair it, leaving a six-inch long scar on my chest – and a lasting psychic wound. I have protected my heart like a mother lion protects her cubs ever since.

Which is why when I learned my cholesterol had skyrocketed I went into survival mode. That cholesterol was coming out of me one way or another. The way I chose: I switched to a strictly vegan diet.



Over the years I’ve been asked many times about eating vegan. But first-hand I’d only played with veganism and had learned it can be a pain in the ass hunting and gathering vegan food. Besides which, I am a meat lover. But I saw my unfortunate situation as an opportunity to experiment for myself and my clients. So once again I became their guinea pig.

(Note: Just as with going keto, the outcome of my eating vegan experiment is the result of one guy’s journey. You might have different results. In fact, I’m sure you will. To repeat: everyone’s different. But I’ve talked to a lot of vegans and I can tell you the effects the diet had on me over the course of five months were not atypical.)

First, here’s what eating vegan looked like: I cut out a lot of fat. I’m talking as much fat as I possibly could. And I said a so-long to all animal protein, a sad goodbye to my beloved eggs, and later days to all dairy, and I even cut back on eating nuts and healthy oils, like avocado and olive. Again, I was determined to flush that cholesterol out of my blood. So how’d did it all go?

For the first three months, going vegan went great! Sure, it takes more effort to hunt down and gather vegan food, but these days most restaurants offer vegan choices. Also, I think not eating animal flesh soothed my conscience; I really felt good about myself. And I loved the food I was eating, all the protein-rich quinoa, the myriad of vegetables – both raw and steamed – and I got to eat carb-infested sweet potatoes and brown rice again, as well as fruit – fruit! How I’d missed raspberries and blueberries. I also added plant protein supplements to my daily diet. So going vegan looked something like this: 20% fat, 20-30% protein, 50-60% carbs.

As for performance, during those first months I had very few changes to my body composition (muscle tone, fat percentage), energy level, or strength. But in the fourth month, it was as if someone flipped a switch. I started losing strength quickly. During weight training, a 20-kilo kettlebell felt like it weighed 40 kilos. And my body began changing too. I started looking thinner yet softer, my muscles lost tone, and during runs and rides, whether short intervals or long, slow endurance work, I didn’t have the same power or stamina.

At the end of five months, I had gained 3 percent body fat, but lost 2.5 pounds, all of it muscle mass. How about my cholesterol, the chief reason why I turned to eating vegan in the first place? A precipitous drop from 280 to 135. The lowest it’s ever been. Talk about mixed messages. Now what do I do? And what do I tell my clients?

I wished I could stay vegan. I loved eating that way. And I told my clients if they can live with the restrictions they should try it too. But me? I couldn’t continue eating vegan. Part of my job training professional athletes like top motocross rider Ken Roczen is to train with them. Running up mountains, cycling 70-100 miles, doing hours-long weight and cardio circuits, pushing them hard so they get fitter. So I have to be as fit as possible, especially since those guys are half my age! So from a professional standpoint, eating vegan just wouldn’t work for me.

So what’s the answer? What is the perfect diet we’re all seeking? I knew I was going to have to experiment further to learn what’s most perfect for me. Which I did and found a happy place that I’ll tell you about in my next post. Or if you can’t wait, pick up a copy of my book, “Rebound.” You can find the answer in the chapter called, “Nutrition.”

About Peter Park

Peter Park is a three-time winner of the World’s Toughest Ironman and current record holder of several endurance competitions including the Catalina 50-mile ultra-marathon. As a strength and conditioning coach, Peter has twenty-eight years of experience training elite athletes like 2017 National League MVP, Giancarlo Stanton, 2017 World Series champion, Justin Verlander, and pro surfer Lakey Peterson. Peter also works with musician Harry Styles, actors Rob Lowe and Don Johnson, executives Irving Azoff and Chris Silbermann. Peter is the author of two books, “Rebound: Regain Strength, Move Effortlessly, Live Life Without Limits,” and “Foundation: Redefine Your Core, Conquer Back Pain, and Move with Confidence.” Peter owns Platinum Fitness, his Summerland gym, and lives in Montecito with his wife, Kelly and two sons, Hayden and Carter.



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