Marks Daily Apple
Serving up health and fitness insights (daily, of course) with a side of irreverence.
13 Aug

Dear Mark: Coffee and Insulin, Fat and Post-Workout Meals

In today’s edition of Dear Mark, I cover two topics near and dear to many of your hearts. First, I discuss the interaction between coffee intake and insulin. Does coffee stimulate its secretion? Does it impair insulin’s function, or our body’s reaction to it? Find out how you should approach coffee on a Primal Blueprint eating plan. Then, I explore the suitability of dietary fat in the post-workout meal. Does it belong? Should you be stocking skim milk, de-fatted chicken breast, non-fat yogurt, and cartons of egg whites for your post-workout meals? If you’ve just lifted something heavy, should you therefore shun the yolks and fear the fat for the rest of the day? Find out below.

Let’s go.

Does coffee raise insulin levels? A lot of contradictory stuff out there. Hoping you could get to the bottom of it. Also, how does it affect GABA?



What makes coffee research so confusing is that a lot of it is actually caffeine research. You see, researchers love isolating whole food constituents to avoid confounding variables. It’s easier to get a definitive result about caffeine than it is to get one about coffee, because coffee contains huge and diverse levels of antioxidant compounds. If you don’t, and coffee has a health effect, how do you know if it’s the caffeine or something else in coffee causing the effect? That’s helpful, but most of us are drinking coffee – not popping caffeine pills. So, while caffeine is definitely one of the main active compounds in coffee, it’s not the only one. Adjust your interpretation of “coffee” research accordingly.

That said, both caffeine and coffee have been shown to exert negative effects on insulin sensitivity. Not on insulin itself, though. As standalone substances (without a meal to accompany them), neither caffeine nor coffee have an independent effect on insulin secretion.

But insulin sensitivity, the efficiency with which your body handles incoming glucose? Yeah. Caffeine tends to reduce it. It’s not necessarily a terrible thing, though, when you consider why this occurs. Caffeine increases adrenaline, which increases lipolysis – the liberation of fatty acids from body fat. The increased sense of energy you get from coffee is partly caused by the increased availability of energy in the form of free fatty acids. Of course, an increase in free fatty acids shooting around your body causes a subsequent – and necessary – drop in insulin sensitivity to allow you to actually burn the fat. It all makes perfect sense when you consider the entire picture, but it sounds pretty scary out of context.

Despite all the clinical trials showing that acute intakes of caffeine and coffee tend to reduce insulin sensitivity, the overwhelming majority of the observational literature finds that coffee is linked to lower body weight and protection from type 2 diabetes. Heck, heavy coffee drinking is even linked to protection against non-alcoholic fatty liver disease, an affliction characterized by insulin resistance. And although what I’ve said about correlation and causation in the past holds true in this case (even though it’s supporting something that we might like), the connection is undeniably interesting, especially when you consider that heavy coffee drinking is universally lauded as unhealthy and that habitual coffee drinkers are probably more likely to smoke, stay up late, and eat bad food. Perhaps there is a mechanism there (one suggestion in the NAFLD paper is the antioxidant content of coffee).

Part of it stems from the fact that habituation to a behavior affects the effects of that behavior. You know how once you’ve been drinking coffee for awhile, you don’t really get the “buzz” anymore? You still love (need) the stuff, but it’s not so much a stimulant as it is a normalizer. Well, the coffee buzz comes partially from adrenaline, the secretion of which drinking coffee promotes. Adrenaline is also a potent stimulator of lipolysis, the release of free fatty acids from adipose tissue. Since the liberated fatty acids are causing the temporary insulin resistance, and the fatty acids are liberated by adrenaline, and the adrenaline buzz is lessened with habitual coffee drinking, maybe the insulin resistance is similarly lessened when you’re a coffee fiend. Sounds sensible, right, but what does the research say?

Sure enough, when you give overweight, generally healthy habitual coffee drinkers five more cups a day and measure their “biological risk factors for type 2 diabetes,” things look a little different. Their insulin sensitivity not only stays the same, but their risk factors actually improve. Markers of both liver function and adipose tissue function were improved after upping their coffee intake.

What does all this stuff mean for real world coffee fans?

  • Moderate your carb intake when drinking coffee. Some fruit and maybe even a bit of sweet potato hash can be okay, especially if you’re glucose tolerant, but for the most part, stick to eggs and bacon with your coffee in the morning. And whatever you do, don’t be one of those pudgy carb-loading cyclists clad in spandex I see at the cafe quaffing coffee and pounding kruellers. That’s not a good combo.
  • Get up and move around a bit when you drink. Since that coffee has just liberated a bunch of fatty acids from your adipose tissue, use them! Go for a walk, take a stroll around the office, do some gardening, hit the trails, ride your bike, play with your kids. Just move. If you don’t, the bulk of those fatty acids will simply be recycled back into your body fat.
  • Remember that coffee isn’t just caffeine. It is a whole plant food/drink with hundreds of bioactive compounds beyond just caffeine, like chlorogenic acid, which may have protective effects against type 2 diabetes. Those compounds come from and are affected by the environment, soil, elevation, climate, and region in and at which the coffee was grown. Even the roasting temperature changes the antioxidant content and composition of the beans. The taste and health effects of coffee thusly depend on dozens of factors, and that’s why coffee has different effects on different people as reflected across dozens of studies. Coffee isn’t coffee isn’t coffee. The coffee that tanked those people’s insulin sensitivity in that study may have been a mass market blend from Starbucks, while the single origin coffee from a little Guatemalan plantation could have totally different effects (or it could be the other way around).

Of course, as the ruler of Asgard, father of Thor, and a mighty Norse god, you can probably get away with eating tons of carbs with your coffee (served in a drinking horn, no doubt).

Hi Mark,

I have read somewhere that fat intake is not recommended post workout because it slows the ingestion of protein and carbs. Is it true? If yes, can I take your protein supplement post workout?



Most training blogs recommend that post-workout fat intake be kept relatively low. There are a couple reasons usually given:

  1. If you’re trying to gain muscle mass, you’re going to be eating big after your workouts. Assuming you’re eating a ton of protein and carbs to jack up your insulin levels for the anabolic effect (insulin, after all, shuttles all sorts of nutrients into your cells – protein and glycogen into muscles, for example, after a workout), and your calories are high (to facilitate weight gain) enough, any “extra” fat in the meal has a good chance of being shuttled into fat cells. Thus, from that perspective, fat is “wasted” calories.
  2. If you’re trying to shuttle nutrients into muscle cells, you want insulin as high as it can get, and “everyone knows” that even a modicum of fat will blunt the post-workout insulin spike. Right? Not exactly. One study found that a mixed meal of 47% carbs, 26% protein, and 27% fat – certainly lower fat than most Primal people eat normally, but definitely not a “fat free” post-workout meal – increased insulin levels to 3x fasting at 30 minutes and 5x fasting at 60 minutes (PDF). That’s certainly enough insulin for training adaptations, I’d say. Another study found that post-workout whole milk actually led to greater levels of muscle protein synthesis than post-workout fat-free milk, even though the fat-free stuff had more protein than the whole stuff. Huh, it’s almost like milk is supposed to be whole.

Clearly, some fat after the workout isn’t going to kill you or render your workout useless (and it might even increase protein utilization, at least when it’s consumed as a whole food). And although I’m definitely biased – the fat in my protein supplement (Primal Fuel) comes from coconut milk – coconut milk is rich in medium chain triglycerides, which seems more acutely beneficial to exercise performance than longer-chain saturated fats, at least in rodents.

Stick to the fat inherent in your food – don’t fear meat, fatty fish, and whole eggs – while avoiding dumping copious amounts of butter on your post-workout meal and you’ll be okay.

That’s it for today, guys. Send along any more questions you have and feel free to leave some in the comment section. Thanks for reading!

You want comments? We got comments:

Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

  1. I’m so glad to hear that coffee won’t kill me! If you told me that coffee would make me grow a third arm out of my skull, I’d probably still drink it. A possible, small decrease in insulin sensitivity? I’ll take it!

    Christa Crawford wrote on August 13th, 2012
  2. Oh coffee..

    1) how long after drinking coffee does the (inch or so of) fat covering my steel-hard abs melt off and enter my bloodstream?

    2) I quit coffee about nine months ago (three days of hell, but people tell me it’s nothing compared to giving up sugar) because I didn’t like the thought of it numbing my adrenal receptors. These days I drink about one cup a week, but I’m looking forward to these caffeine-free varieties that I believe are due for harvest this year.

    RC wrote on August 13th, 2012
    • Extra cortisol resulting from too much caffeine could possibly promote fat storage.

      Animanarchy wrote on August 15th, 2012
  3. My grandma and uncle have coffee farms in kona hawaii. Love the smell of it…wish I loved the taste more. Some of you coffee lovers should have been born into their lineage-not me!! :)

    amy wrote on August 13th, 2012
  4. Coffee / Fasting Question! — I’ve been fasting every morning and sometimes drink black coffee (along with water and tea.) Is it okay to sprinkle things into my coffee (cinnamon, etc?) I see some people put coconut oil in there, is coconut cream okay as well?

    Please advise, I don’t want to screw up my fasting state because I’m getting bored with the plain black coffee,..

    jen wrote on August 13th, 2012
  5. I gave up caffeine 8 days ago. I hate coffee my delivery system was sugar free Rockstar (bad I know) at four cans a day it was time to quit. I don’t know of anyother way to cleanly get caffeine in so it’s out. The withdrawal was brutal I still have some symptoms but it’s getting better.

    Muttley wrote on August 13th, 2012
    • Congratulations. I think only people who have gone through it can appreciate it.

      RC wrote on August 14th, 2012
  6. I’ve run into some studies where they found out that the casein protein in milk binds with the beneficial flavonoids in coffee, tea and berries, and renders them useless.

    So adding milk or cream to your coffee or tea might be a bad idea?

    Not sure though whether it rendered the flavonoids completely useless, or only slowed down their digestion and absorption…. can anyone confirm?

    Skaven252 wrote on August 13th, 2012
    • I’ve very interested in this, too.
      Do u remember where u read that?

      Judy wrote on August 14th, 2012
  7. Great post Mark!

    Personal Trainer wrote on August 13th, 2012
  8. Spicegirl, the cinnamon and cardamom coffee sounds yum, I’m going to try it. Your comment about Maca concerns me though… I take Maca daily in an attempt to regulate my (female) hormones; do you have information to the contrary? Sorry to go off topic a bit, but Mark or anyone else here, do you know much about Maca? Thanks.

    Sally wrote on August 14th, 2012
    • I’ve been taking maca daily for the past month and for the first time in 30 years my PMS symptoms have vanished. I’ve never read or heard about any negative side effects; just not to take massive doses of it in the beginning. Side note: mix it with cocoa and white clay powder for a great face mask; moisten with a teaspoon of cream. Your skin will glow!

      jen wrote on August 14th, 2012
  9. Great post man. I love coffee.

    John wrote on August 14th, 2012
  10. I have bulletproof coffee every morning and sometimes one later in the day, organic coffee/MCT oil/30g organic grass fed butter, kerrygold is good but Yeo Valley is better! I also cycle, i cycle to work and cycle for the sake of it, i also lift heavy (5×5 stronglifts) and HIIT (Shin Ohtake Max workouts)my diet is probably 90-95% primal which accounts for my cheat day i suppose. My post workout drink is organic goat whey protein with coconut milk and a tablespoon of pure cod liver oil and /or a raw egg, its the only way i can take cod liver oil, i’ve been having this for about 2 years and i’m doing OK :)
    I also read some time ago Vince Gironda mentioning you need fat to help digest the protein, seems to work for me.

    Dave UK wrote on August 14th, 2012
  11. As an aside and additional potential benefit of coffee, I find it curbs by appetite and especially my sugar cravings. Great comments all around!

    Edible Harmony wrote on August 14th, 2012
  12. I drink a lot of coffee myself and I think the various health benefits are incredibly interesting.

    I try to buy organic coffee from a nearby health food store. I do find that the quality is much better than the generic store brands, both the flavour and the “buzz” are completely different IMO.

    Kris wrote on August 14th, 2012
  13. Nice info on caffeine and coffee. For those that want to know about lowering the insulin spike after meals you can just go for a light walk. 5 minutes of any kind of light exercise lowers insulin.

    Mario wrote on August 14th, 2012
  14. Any of you coffee lovers roasting your own? I use a standard chicken rotisserie and a small drum to roast green coffee beans on my grill. Takes about 15-20 mins to roast a lb. and I guarantee that you have not had coffee til you have had fresh roasted. It is a bit more work than store bought, but it’s not even the same drink. Caution: you will become jaded and have a hard time drinking commercial coffee after you learn to roast your own.

    Nick wrote on August 14th, 2012
  15. Since turning 20, I’ve been having problems with coffee. After a few sips I usually crash and feel out of it for hours to come.

    it’s a similar feeling to a sugar crash I’ve been getting since going primal after eating desert.

    I’ve tried drinking coffee multiple times, mostly without milk or sugar and always have the same results. Even with decaf.

    I haven’t tried again since going primal.

    However, I’m able to drink lots of tea (pure, unsweetened) with no problems. I usually drink 3-6 cups a day!

    Any ideas?

    Eric wrote on August 14th, 2012
    • Please, allow me to diagnose you over the internet:
      First guess would be the quality/source of said coffee – organic, fair trade, folgers… Decaf is often made with nasty chems, and, let’s face it, folgers just ain’t real, crystals or no.
      Second would be the Brewing method – drip, percolator, espresso… I’ve found espresso to be very low acidity & gentle compared to standard drip.
      Third, maybe your adrenal system is easily knocked out of whack? I know my 20s were a time of weird sleep patterns, inconsistent dietary practices, and lots of stress.
      Fourth, I just read what primal pat suggested above about glutenaceous molecular structure. If that’s true, it’s something to really think about.

      Erok wrote on August 14th, 2012
  16. thank you Mark! You just answered 2 of my most burning questions! I’m 1.5 hour post workout. Just had a coffee blended with coconut oil with my low carb lunch. Sounds like I did o.k…

    steffturner wrote on August 14th, 2012

    Dave PAPA GROK Parsons wrote on August 14th, 2012
  18. All good info, Mark.

    Over the years, I’ve gone from coffee (sweetened) to tea (sweetened) to tea (unsweetened). My fave, by far, is tea (unsweetened) – especially when it’s my fave brand, Yorkshire.

    The day’s gotta start with it. Recently there was a whole day I couldn’t have any because of a test I was doing. It made me very cranky.

    A little addicted, maybe? I don’t think so. I see my tea as a big huge life pleasure. Sipping away at it makes me feel like everything’s all right in the world.

    In the course of Grocking on, we’re supposed to include well-chosen pleasures, right? This is mine. No matter what its effect is on my insulin (or whatever), I’m sticking with it. :-)

    Susan Alexander wrote on August 14th, 2012
  19. I am so confused about coffee. I just love having a cup in the morning. Since it raises insulin levels, and therefore can keep that belly fat stuck like a donut around my waist, at least that is what I have read and heard from nutritionists, it really has taken the joy out of drinking coffee. I now feel guilty whenever I indulge. And to top it off, I now see warning signs at Starbucks that the way the beans are roasted can cause cancer. Arrgghhh!!!!

    Marla Martenson wrote on August 14th, 2012
  20. When I drink coffee I usually do 2 shots of espresso with 1Tbsp of grass fed butter and 1Tbsp Coconut oil. It is to die for. No sugar or cream needed.

    Tyler wrote on August 14th, 2012
  21. I used to love coffee with enthusiasm to match many of those posting here. Had to detox for a medical procedure and decided i never want to endure that withdrawal again. It’s great to wake up and have zip naturally. After caring for my mom in the last months of esophageal cancer and reading about the impacts (sometimes asymptomatic) that coffee has on the lower esophageal sphincter, I’ve decided to avoid it.

    Danielle Thalman wrote on August 14th, 2012
  22. Hi Mark, great info about coffee. I agree, there’s definitely more to the story. With regard to the acute effects on insulin sensitivity, decaffeinated coffee is better than placebo, but regular coffee is better than caffeine alone (and decaf is better than regular) ( Does this mean something else in coffee is inhibiting a negative effect of caffeine?

    Bill wrote on August 14th, 2012
    • Yes, the chlorogenic acid in coffee improves insulin sensitivity. From the balance of studies I’ve read it appears that the beneficial effects of chlorogenic acid (and likely other compounds in coffee to some extent) outweigh the negative effects of caffeine in most people, hence the conflicting results when considering caffeine vs. coffee studies with respect to insulin sensitivity.

      Anne wrote on March 17th, 2013
  23. Hi, Can anyone tell me why I get severe muscular aches in the tops of my legs whenever I give up coffee for a few days? It’s baffling.

    wendy howard wrote on August 15th, 2012
  24. I guess its a personal thing but I love my morning coffee/s.

    I fast very day until 12 noon so my black coffee and cinnamon really help fill the gaps and ‘fuel’ my workout more mentally.

    If I can drink lots of water and 1/2 cups of coffee per workout (am) then I find everything works Great. My rule is no caffeine after training, seems to work ok

    Nathan wrote on August 15th, 2012
  25. Coffee: try making coffee as the people who “invented” it make it, i.e. a la Turkish coffee Fell in love with Turkish coffee in Greece (where it is called … you guessed it, Greek coffee), only proper Italian espresso beats it.

    Jan Rendek wrote on August 15th, 2012
  26. As someone who writes regularly on coffee and recommends that one eat before and not after exercise, this article confuses me, especially after your fasting after exercise article.

    Perhaps it is because my target audience is trying to lose fat rather than an audience of elite athletes trying to bulk up.

    If you are trying to lose weight or build muscle, you should only eat before and not after a workout. Ditto with sports drinks, or better yet have salt and minerals in your paleo food, then drink water. The workout if done at high exertion will bring down your blood insulin curve that had elevated from the meal. Biologically you can only burn fat stores when insulin levels are low. This effect persists until you eat again, so if you eat after exercising, you stop the metabolic fat burning.

    Karen Vaughan, MS Oiental Medicine wrote on August 15th, 2012
  27. I’ve recently run into a health issue where if I wasn’t ‘strict’ Primal before, I have to be committed now…with some caveats. The absolute worst for me being I cannot have coffee (or tea)! Not even for the caffeine, but because apparently coffee/tea tend to have molds. I need a stimulant in the am, so I am doing a fat-burner that has about 100mg of caffeine plus some other stuff.

    I’ve noticed that a) even if I drink a cup of hot water with the supplement, I don’t get the same ‘diuretic effect’ if you catch my drift, and b) I don’t seem to have the same type of energy throughout the day as the regular coffee (I average 1.5-2 cups a day).

    Hopefully I will be able to go back to the one luxury I have left soon (dying over here!), but would be incredibly grateful for any suggestions on brands or ways to avoid possible mold/contamination…!

    Jessica wrote on August 15th, 2012
  28. I’ve read that coffee can trigger autoimmune issues in people with gluten intolerance. Is this true?

    Jen wrote on August 15th, 2012
  29. Everyone I know always refers to the “golden window” of time after the workout when getting the right food in is super important.

    PrimalQueen wrote on August 19th, 2012
  30. What about decaf coffee?? I have been drinking that for years due to being pregnant (3 kids later) and I still continue to drink it.

    redsnapperuk wrote on August 24th, 2012
  31. Great post. I am a type 1 diabetic, well into my 4+ years paleo journey, and no one has been able to describe the biochemistry of coffee/insulin resistance. Much appreciated. The paleo journey can have some questionable areas and through diabetes in the mix, and you have one science experiment.

    Kelly O'Connell Schmidt wrote on August 27th, 2012

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