Dear Mark: Oxidized Coffee Oils, CrossFit or PBF After Injury, Enduro Mountain Biking, and Pressure Cookers

Cup of coffeeFor today’s edition of Dear Mark, we’ve got a four-parter. First, is it a problem if the oils in coffee beans are oxidized? Should we avoid them altogether? Is coffee coffee? Next, what should a guy who just recovered from an injury do for exercise: CrossFit or Primal Blueprint Fitness? After that, an enduro mountain biker wonders whether her interval-less training program could benefit from a few interval workouts. If you don’t know what enduro mountain biking is, you’ll find out below, so don’t worry. And finally, I explore the benefits and any downsides to using a pressure cooker to cook your soups, stews, and broths. Are we destroying nutrients?

Let’s go:

Hi Mark,

I have been roasting coffee at home for about a year now and I will never go back to buying old, stale coffee from the store. That got me thinking though…what oils exist in coffee? Are the oxidized oils covering the store-bought coffee much worse than the oils in fresh-roasted coffee or does the roasting process oxidize the oils anyways?

Thank you for all you do,


Have you ever opened a bag of coffee to reveal a sweltering throng of greasy, sweaty black beans that clog your grinder and leave a film in your mug? Those are coffee oils rising to the surface after (excessive) roasting. They’re now exposed to the air and, being roughly half linoleic acid, almost certainly oxidized.

The lighter the roast and the fresher the coffee, the lower the oil oxidation. Keeping it in whole bean form also increases the resistance, while grinding it prematurely will oxidize the oil and mar the taste.

All that said, I find fretting over the health effects of oxidized oils in coffee unnecessary. Consider that the vast majority of evidence, both epidemiological and controlled, points to coffee in general being incredibly beneficial. It seems to reduce the risk of diabetesall cause mortalityAlzheimer’s diseaseParkinson’s disease, and liver cirrhosis. These studies mostly consist of normal coffee drinkers enjoying normal coffee, not the small minority of folks consuming only single-origin light roasts. And dark roasts even seem to be better than light roasts at increasing antioxidant status and reducing bodyweight in healthy coffee drinkers.

The best reason to avoid oxidized coffee beans is because you don’t like the taste. Don’t stress the health effects too much.

For the Dear Mark session I have the following question:

I am a 36 year old who used to have 100lbs of overweight 14 months ago. I started 14 months ago. Eating primal. And following a fitness program made for me by a personal trainer, which was basically bodyweight excercises. Lost approx 50lbs in 6 months.

My personal trainer then advised me to advance to doing CrossFit. Although I hesitated, I had a go at it. The eight months that followed were both positive and negative. I lost another 16-20lbs, but it didn’t go as smooth as the first 6 months. I got more cravings for carbs, got several injuries that prevented me from several exercises and even had me out of the gym for two months.

My question to you is: what is your suggestion now that my injury is healed. Get back into the CF gym? Or go back to, for example, PBF LHT with my bodyweight and first try to get stronger and lose the 40lbs of fat I still have to get rid of?

Question 2 if your answer to question one is PBF:

I don’t have a pull up bar in my house and I hate the iffy things people install on their doorposts etc (too many fail videos on youtube lol). Is there any other way to do pull up progression? Maybe TRX?



Hi, Bart.

Question 1: Without knowing the CrossFit box in question, it’s tough to say.

I lean toward the program that already worked without causing injuries. You can always move on to something else, but you know it’s a safe option and it’s already worked. It’d be a nice way to ease back into regular training.

If you go back to CrossFit, see if you can focus on strength training. Many CF boxes have different tracks. They’ll have an Olympic lifting track. A strength training track. A more traditional metabolic conditioning (WODs) track. In your situation, I think a focus on strength is safest. This will build strength (obviously), strengthen your joints and connective tissues (so they can take the pounding you receive during high intensity WODs), and get you familiar with many of the movements commonly performed at high speed for time. Otherwise, I worry your body will just break down again.

Later, after building up your strength and mastering the lifts, you’ll be ready to handle more high intensity metabolic conditioning – if that’s what you want to do.

Question 2: Yes, a TRX setup will work, as long as you have a suitable overhead horizontal anchor point to work with. You can use vertical anchor points, but you won’t be able to do pullups. Another option is a set of gymnastics rings. I can vouch for these rings, and I’d actually recommend rings over TRX because the room for growth is much higher with the rings. TRX is designed for beginners (which is awesome, don’t get me wrong). Rings are designed for beginners and Olympic athletes.

The advantage of TRX or ring pullups is the freedom of hand positioning. You can do all sorts of different pullup positions on rings or straps, whereas with an overhead bar you’re limited.

Also, any stable (or even slightly unstable) horizontal overhead surface can work as a pullup bar. Got any overhead beams or ledges? A ledge restricts your grip and forces you into fingertip pullups, which are excellent builders of grip strength. Or how about trees? A tree branch is great, and I’ve always found I can somehow do more pullups on a tree branch than on a pullup bar. Not sure why. If you have access to the underside of a stairwell, you can do pullups there, too. The world is full of pullup bars once you start looking.

Dear Mark,

I am a competitive ‘enduro’ mountain biker living in Ireland. I compete in the Enduro World Series and other international races. I have just been given an 8-week training programme from a personal trainer (who is a ex professional downhill racer) and after reading your latest post on interval training vs endurance I’m confused as to what to do.

My programme is 2rs on road bike/turbo trainer, 3 x per week; 2 x strength training per wk, Saturday skills on mtn bike, and a 6km mountain run on a Sunday. The aim is to condition my muscles and lose body fat. However, after reading your article, it sounds like I should be doing interval training which will reap the same benefits as long hours on the bike. Is this true in my case? Where I’m in pre-season training (race season begins in April) is it better for me to go with interval instead?

I appreciate the number of emails you must get so at your convenience.

Kind Regards,


Great question, Michelle. Although I’ve never done much mountain biking, I have quite a few friends who are heavily into it and the rise of enduro racing has really intrigued me. For those who don’t know, enduro racing involves timed downhill portions with untimed uphill climbs to get to the start of the next downhill leg. It seems to require a mix of skill (sprinting down a mountain trail with jumps and quick turns and rocks and roots takes great precision and on-the-fly decision making), endurance (though the climbs aren’t timed, you still have to do them fast to get to the next downhill race), and strength (mountain biking takes a lot of lower body strength and a surprising amount of upper body strength).

Check out this video from a race in Colorado. Looks like a heck of a lot of fun.

Many enduro downhill legs last about ten minutes, with full-out sprints on the straightaways. And “downhill” doesn’t mean a straight shot down. They also include lots of climbs, even though the overall trend is downhill, so you need to be able to push hard up the inclines. Intervals definitely have a place in your training because your events resemble intervals.

Intervals do work. When you’ve got marathoners and triathletes and other exclusively endurance athletes using interval training to improve their performance, there’s no question athletes whose events actually resemble intervals can benefit from training them, too.

That’s not to say you should give up the longer rides. They’re valuable, too. And hey, you can always embed interval training into those longer rides.

Intervals can be longer than the 20 seconds on, 10 seconds off Tabata-style intervals that are popular in science reporting and probably aren’t even the most effective way to improve performance. You can do several sets of 4 minutes on, 4 minutes active rest. You can do 15 seconds on, 15 seconds off. They both increase endurance more than moderate training. Other research indicates that shorter intervals work best with longer (relative) rest periods, and longer intervals with shorter (relative) rest periods. So instead of 30 s on/30 s off, you’d rest for 4 minutes. Or if you were using 4 minute work periods, you’d only rest for 1:30. A mix of each would probably be best. Short and intense intervals with longer rest periods, plus longer, easier intervals with shorter rests.

Of course, I can’t tell you how to structure your program. I don’t have any specific experience in training mountain bikers and I’m certainly not a former downhill professional. But I would run the interval stuff by your trainer to see what he or she thinks.

Mark – What side do you take on using pressure cookers in making broths/stocks and soups/stews?

Does this in any way affect the nutritional content in meats and or vegetables?



I love the pressure cooker.

Cook a whole chicken in 45 minutes. Fall-apart beef shanks in 50 minutes. An hour or less for rich viscous chicken broth that gels at room temperature. What’s not to love?

But it does expose food to higher temperatures than regular sea-level boiling (250 degrees °F/121 °C versus 212 degrees °F/100 °C). And since we have the notion that higher temperatures destroy nutrients, it’s natural to worry about the nutrient content of our pressure-cooked food. But should we?

No. Research indicates that pressure cooking is gentler than most other forms of cooking and actually preserves a lot of nutrition.

In spinach (and amaranth leaves, if you can get them), pressure cooking preserves the vitamin C and beta-carotene content more than open pan cooking (which sounds like sautéing). It also preserves calcium and increases iron absorption.

Broccoli is great in a pressure cooker, retaining 90% of its vitamin C and almost all of its sulforaphane (a very healthy broccoli phytochemical, perhaps the best known and most studied).

Pressure cooking uses less water than other cooking methods, minimizing the leaching of nutrients. If nutrients are lost, it’s not to the ether; it’s to the cooking liquid. And since soups, stews, and broths involve consumption of the cooking liquid, you won’t be missing out on much. Soups, stews, broths, and any other dish where the liquid is consumed with the meal are thus perfect for pressure cookers.

Most pressure cooking research centers on nutrient retention and loss in grains, legumes, and vegetables, but there’s at least one reference discussing how it affects fatty acid and cholesterol oxidation in mutton (and, I presume, most other animal products). Anytime you cook meat, you’re going to oxidize some of the fat and cholesterol. It’s an unavoidable consequence of applying heat to these substances. However, compared to broiling it, pressure cooking mutton results in fewer oxidative changes.

Oh, I almost forgot one more thing. Anti-pressure cooking zealots (sure, they exist) often bandy about the “denatured protein” canard: “Using a pressure cooker will denature the protein in your food and forever alter the structure of the amino acids. Also something about enzymes.” To that, I say: “Great!” I love denatured animal proteins. Denatured proteins are generally more digestible than undenatured proteins. We’re always denaturing the proteins we eat before we eat them. It’s kind of the whole purpose of cooking. When we cook egg whites, the proteins become denatured and more digestible. When you stick seafood in a lime juice bath to make ceviche, you’re denaturing the proteins. That doesn’t “destroy” the proteins or make them toxic or carcinogenic or unrecognizable to our easily-fooled digestive enzymes; it just rearranges them. They’re still broken down in the gut into amino acids.

If you’re convinced, I’m a big fan of the Instant Pot electric pressure cooker. You hear a lot of horror stories about the stove top pressure cookers exploding and coating the kitchen and its inhabitants in molten chili. That’s impossible with the Instant Pot. Very difficult to mess up. And making bone broth is a cinch in one. Just add bones, water, and press a few buttons. It even has a sauté mode, so you can brown your meats before braising them without getting another pan dirty.

That’s it for today, everyone. If you’ve got any additional comments or advice for today’s round of questioners, chime in down below. Thanks for reading!

About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

If you'd like to add an avatar to all of your comments click here!