For today’s edition of Dear Mark , I’m answering questions from last week’s post on coffee and fasting . First, is cortisol a bad guy all the time? Next, what about non-dairy powdered creamers? Good, bad, breaking the fast? How does thyroid hormone replacement therapy affect the fast? Is a “tiny amount” of protein disastrous to a fast? Can you take BCAAs during a fast and maintain the benefits? Can I still drink Frappucinos? And what do I think of Dr. Panda’s take on coffee triggering the digestive system and thus negating the effects of a fast?
So coffee increases cortisol. Is increasing cortisol a beneficial or detrimental thing to do during a fast? I speculate that it would add to stresses in the body but I suppose it matters how well a person manages cortisol.
Cortisol relays messages about the outside world to the cells, tissues, and organs inside you. If cortisol is high, your body receives an “alert” message. Things are happening. It’s dangerous out there. It’s dire. You need to move. You need to act. You need to be alert. You need all systems trained on getting you safely through the storm. Cortisol helps with that.
When cortisol spikes, you actually release more fat from body fat stores and, in concert with adrenaline, burn it. This is helpful during exercise or any other situation that demands extra fuel.
These effects are flipped in the presence of chronic levels of cortisol activation. Chronic cortisol leads to fat gain  (especially belly fat ), lower energy levels, depressed cognitive function. You can’t run at top speed forever. The wheels fall off.
It’s the classic acute vs chronic dichotomy we see in everything.
Laid atop an established pattern of chronic stress and cortisol activation, coffee during a fast could makes things worse. But if you’re chronically stressed, you probably should take care of that before you get deep into intermittent fasting.
If you’re fasting on purpose, if you’ve decided to incorporate fasting into your healthy lifestyle and you’re sleeping well, you’re eating well (when you’re not fasting), you’re training regularly, the effects change. A little cortisol isn’t anything to worry about.
Can someone explain how non-dairy powdered creamers play into this?
I assume because it’s processed it must be bad, but what impact does it have in our diets and especially with fasting?
Many non-dairy powdered creamers are awful, made from hydrogenated vegetable oil. Avoid those.
I’m a big fan of powdered MCT oil . You can whisk that into some milk or directly in your coffee for a great “cream” effect. The brand I use just has some soluble corn fiber, sunflower lecithin (choline source), sodium caseinate, and sodium dioxide to enhance the creaminess.
In case you’re unaware, MCTs are medium chain triglycerides, a class of fatty acids that convert more readily into ketone bodies than other fats. They can really help beginners extend and tolerate the fast.
They do “break” the fast, however.
What about prescription medications and autophagy? I take daily thyroid meds in the morning on an empty stomach. Since I fast til lunch, I can push this forward until 9 or 10 am, keeping it within an overall 10 hour window (eating in just 6 hours). Sometimes I think it would be good to fast 36-72 hours to really amp up autophagy, but is that a waste of time if I still take the meds?
I can’t speak to meds in general, but thyroid hormone  is actually a major player in the regulation of autophagy, particularly in the liver, where it upregulates autophagy and preserves mitochondrial function , enhances mitochondrial turnover and protects against carcinogenesis .
Meanwhile, low levels of thyroid hormone increase thyroid stimulating hormone, which leads to depressed autophagy and increased cell death .
This is endogenous thyroid hormone, not prescription. The effects may differ when you’re taking it in a pill, but since those pills are meant to emulate our natural production of thyroid hormone, I don’t think it’ll differ very much.
In the tea post, would you please clarify effects of mixing even tiny amounts of protein with green tea? I read that it reduces the beneficial effects of fat burning.
Adding tiny amounts of protein will likely inhibit autophagy (cellular cleanup and maintenance) but won’t affect fat burning much at all.
Hi Mark, what about taking some BCAA’s during the fast to spare muscles? I’m trying to gain muscle and do my fasted workouts with some BCAA’s in my water bottle. Does this limit the fast? Thanks!
Depends how you’re scheduling your fasts.
If you’re doing a full-on 24 hour+ fast once a week or so, skip the BCAAs. You’re eating plenty of protein the rest of the week and a day without any coming in will be fine. Might even be optimal.
If you’re doing more of a Leangains-style compressed eating window  every day, BCAAs aren’t as much of a big deal. They’ll still “break the fast,” but since you’re going to be working out right after and eating shortly, it’s mostly a wash. Martin Berkhan was a big fan of BCAAs  before fasted workouts.
Frappuccino? would that break a fast?
Those things have enough sugar and calories to break several fasts.
I’m glad you mentioned Dr. Panda. I was wondering the same thing. From what I understand, anything beyond water triggers the enzymes that would prevent a autophagy. Is that incorrect?
My understanding is that anything beyond water triggers the digestive enzymes and starts the “digestive day.” Digestion, like everything else, has a circadian rhythm. Whenever you eat your first meal of the day, your body gears up for a solid 8-10 hours of eating. By the time you’re breaking your fast, the digestive day is winding down and your body isn’t as efficient at handling food.
I don’t think it has anything to do with autophagy.
If you don’t seem to tolerate food very well after a fast, try skipping the coffee.
That’s it for today, folks. Thanks for reading and be sure to help out down below with any further questions, answers, or clarifications.