4 Misunderstandings About Carbs and Stress

The relationship between stress and carbohydrates is confusing, with seemingly contradictory arguments bouncing around the online health sphere.

There are those who say high-carb diets cause stress, and that eating more fat and fewer carbs is the solution.

There are those who say high-fat diets increase stress and eating carbs ameliorates it.

Who’s right? They can’t both be right, can they?


You’d be surprised.

Let’s dig into four common carb questions and assertions.

“Stress Increases Carb Cravings.”

This is well-established. You have a terrible day at the office, your kids have appointments twenty miles apart within fifteen minutes of each other, the traffic is backed up to your driveway, you’re late for work, the dog needs a walk, you haven’t even thought about what to make for dinner, you slept four hours last night—it adds up. People deal with a lot. And in that moment, a carbohydrate-based snack really does seem to take the edge off.

Across millions of years of hominid evolution, the human stress response developed in the context of real-world, short-term, and infrequent but intense stressors: battles, hunts, freak injuries, dangerous animal encounters, interpersonal conflicts. These were situations that demanded heightened senses, available fuel, and a rapid heart rate to deliver everything to the tissues that needed to move and act. It makes perfect sense for your body to pump out adrenaline to increase fat burning and glucose in the blood—you need that fuel to deal with the situation. It also makes sense for your body to follow that up with a blast of cortisol, which makes you crave high-carb junk food to replace the fuel you utilized. The problem is that our modern stressors are too frequent, they aren’t physically demanding, we aren’t utilizing the fuel we mobilize, and we have no real need for the carb cravings that come after.

What happens when we eat too many carbs that we never actually needed?

We get fat. Cellular energy supply becomes overloaded, impairing our mitochondria’s ability to process energy efficiently. This degrades metabolic flexibility—the ability to switch between different fuel sources—preventing us from burning the fat on our bodies in between meals. We become reliant on those carbs, and when we don’t get them fast enough, our bodies perceive that as a major stressor.

So while giving in to carb cravings can reduce stress in the short-term, it sets us up for longer-term, more chronic stress.

“What About Gluconeogenesis? Isn’t That a Stress Response?”

It can be.

A primary goal of cortisol is to increase glucose availability. It does this through multiple avenues. One I just mentioned is to increase carb cravings. Another is to make you insulin resistant, thereby preventing insulin from sucking up blood glucose. Gluconeogenesis—the creation of glucose from amino acids and other substrates—is another.

If you’re a sugar-burner, stressful situations will increase carb cravings, induce gluconeogenesis, and may even make you insulin resistant. If you’re fat-adapted, the story shifts.

A fat-adapted person will have ketones and fatty acids available to provide energy in between meals. A fat-adapted person will have ketones and fatty acids available to provide energy in stressful situations. A fat-adapted person will be able to utilize those ketones and fatty acids during stressful situations—their mitochondria will literally be primed to utilize those fuels, not just glucose. A fat-adapted person is less likely to perceive carbohydrate shortages as stress shortages because they’ve got all this other fuel available to burn.

This adaptation doesn’t happen overnight. If your diet is low-carb or keto, but your body is still reliant on sugar, you will perceive reduced carb availability as a stressor. That’s one of the hallmarks of the keto flu, and it’s one reason why some people have extended keto flu—their bodies are still expecting and demanding glucose.

Some people never get over the carb cravings; they never fully adapt. This is the subset of the population that doesn’t function or perform well on a long-term ketogenic diet. The cause is unknown, at least for now (I suspect it has to do with recent ancestry and genetic proclivities), but what matters is that these people exist. For them, a long-term keto or very low carb diet approach will probably always be stressful. But even in these folks, spending some time in ketosis—through short term low-carb eating, intermittent fasting, or even extended low-level endurance activity that primarily burns fat—is a good idea that will reduce stress and improve overall resilience.

“But Carbs Make Exercise Less Stressful!”

Exercise is stressful to begin with. But then you adapt to the stress and overcome it—and end up stronger, fitter, and faster than before. Without the stress, working out doesn’t work. A legitimate method for increasing your work capacity is to train-low (carb), race-high (carb). Athletes have been doing this for decades—training in a low-carb state to get better at performing without ample muscle glycogen, then going into a race with full glycogen reserves and the ability to perform without glycogen. Exercising in that low-glycogen state is stressful, but that’s the whole point. It makes them better, stronger, faster, and it conserves glycogen for when they really need it.

If you consistently perform glucose-intensive high-intensity anaerobic activity for extended periods of time—CrossFit style WODs done 3-5 times per week, for example—you will run up a glucose debt and should replenish some of the carbohydrates you expend or risk cortisol spikes. Fat-adaptation can improve your tolerance of anaerobic activity in a low-glucose state, but there’s a breaking point, a physiological limit.

Eat the carbs you earn. This is a subtle point I don’t often see made. The reverse is widely understood—don’t eat the carbs you don’t earn—because millions of obese and overweight people do that every day. It’s a big reason why we’re so overweight. But if you fail to eat the carbs you earn through intense, protracted physical activity, you’re creating an undeniable glycogen deficiency that your body may perceive as a stressor. It may turn out that fully fat- and keto-adapted athletes can perform intense medium-to-long-term activities at high levels, and there’s some indication that this is the case, but for the time being it appears that eating the carbs you earn can stave off the stress.

“Low-Carb Diets Are Stressful For Women.”

There’s a glimmer of truth here. Allow me to explain.

Women are inherently more sensitive to caloric fluctuations than men…on average. The reason is sheer biology. Human evolution is concerned with fertility and reproduction. Can you produce, foster, and support viable offspring? Awesome. Natural selection deems you fit.

To fulfill their biological role, men have to produce sperm. They can do so almost indefinitely. They don’t run out; they just make more. If a batch is damaged due to poor lifestyle or dietary choices, there’s more on the way. After a man gets someone pregnant, his biological involvement with the growing baby is done. What or when he eats has no impact on the survival of the growing baby.

To fulfill theirs, women have a finite number of eggs, or “chances.” Once an egg is gone, there’s no replacing it.

And so the body seeks to inculcate the egg from environmental insults.

When you are preparing to get pregnant, your body needs extra nutrients to build up a reserve and “prime the pump.”

When you are pregnant, the growing baby needs a reliable and constant stream of nutrients for almost a year.

After you’ve given birth, the growing newborn needs breastmilk. To make that milk requires additional calories and extra doses of specific nutrients. Modern technology allows us to skip nursing and go straight to the bottle, but your body doesn’t “know” that.

It all points to women being more finely attuned to caloric deficits. For example, women’s levels of ghrelin, the hunger hormone, are quicker to rise after meals. Even if you’re never going to have kids, your body is still wired to protect against these caloric fluctuations.

Where do carbs come in?

One’s carbohydrate consumption is uniquely hewed to our sense of caloric sufficiency. If carbs are plentiful, your body perceives that as a signal of environmental plenty: the weather is good, the plants are producing, the trees are bearing fruit, the men are bringing back lots of honey. Life is good. It’s the perfect time to get pregnant. Above all other macronutrients, carbohydrate consumption increases the short-term expression of leptin, a satiety hormone that signals the presence of incoming calories, caloric sufficiency, and environmental plenty.

There’s also the issue of extreme satiety. Low-carb diets often become low-calorie diets without you even trying. That’s why they work so well for fat loss, by inadvertently reducing the amount of food you eat and increasing satiety. But for some women, especially those at or approaching their ideal weight, going too low in calories can increase stress.

Summing Up…

Are you unable to access your own body fat in between meals for energy? Then you’ll be a ball of stress unless you can get those Jolly Ranchers unwrapped quickly enough. It’ll be a constant battle. And yeah, if you keep pumping yourself full of carbs to keep your blood glucose topped off, you’ll keep stress at bay—but you’ll always be teetering on that precipice.

Are you exercising? Then you should strike a balance between gaining the adaptive benefits of training in a low-carbohydrate state and eating the carbs you earn.

Are you a woman? Then you’re probably more sensitive to diet-induced stress and may benefit from occasional carbohydrate refeeds. You should watch out for excessive satiety on ketogenic diets, which is great for fat loss but can lead to stress issues down the line if calories get too low.

The relationship between carbohydrates and stress isn’t exactly straightforward, but it is navigable. Hopefully after today you have a better idea of where you stand in the relationship.

What’s been your experience with stress and carbohydrates? Has your tolerance for stress gone up or down since going low-carb or keto? Thanks for stopping in today.


Mcallister MJ, Webb HE, Tidwell DK, et al. Exogenous Carbohydrate Reduces Cortisol Response from Combined Mental and Physical Stress. Int J Sports Med. 2016;37(14):1159-1165.

Dirlewanger M, Di vetta V, Guenat E, et al. Effects of short-term carbohydrate or fat overfeeding on energy expenditure and plasma leptin concentrations in healthy female subjects. Int J Obes Relat Metab Disord. 2000;24(11):1413-8.

TAGS:  hormones, Keto

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.

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25 thoughts on “4 Misunderstandings About Carbs and Stress”

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  1. Enjoyable read. As someone who lives a ketogenic lifestyle, and who is athletically active, I am not sure exactly how to go about consuming the carbs I’ve “earned.” I rarely run into problems with athletic energy, at least not below anaerobic threshold. Not sure that eating more carbs will improve my performance. And, if they would improve my performance, how does one go about calculating earned carb replacement without losing the fat burning benefits of ketosis?

  2. Thanks Mark!
    I am on Day 9 of keto after two failed attempts. Previously, I was doing a more conventional keto approach of counting all carbs, yet would end up with severe depression symptoms by Day 3 (I have a history of depression, so I wasn’t willing to “power through” such intense symptoms). However, this time I am not counting above-ground vegetables and I am feeling really good! I think the carbs from nutrient-dense plants have made all the difference!

    Here are my stats, if anyone is interested:
    Avg. Gross Carbs: 50g
    Avg. Non-Veg Carbs: 34g WHAT I COUNT
    Avg. Net Carbs: 35g
    GKI (last three days): 3.75 – 4.85, moderate ketosis
    Avg. Protein: 106g
    Avg. Fat: 126
    Avg. Calorie Intake: 1727

    Female, 26, 157 lbs., 5’7”, apx. 28% BF, moderately active.

    Maybe there’s a reason the typical woman enjoys vegetables more than the typical man? Maybe we need those carbs to communicate to our bodies that the food environment is plentiful and stable? ????? It would make sense!

    1. You might be right on the money there… as a female of 49 I’m having some hormonal changes… reading a fascinating & inspiring book by dr Anna Cabeca~ she was recently on a podcast here. Its about her “keto green” diet, and as well as alkalinity (provided by those green veg etc) it”s the result of years of research & petsonal experience with female hormones & changes. Highly recommend!

      1. Yes! I have been reading some of Dr. Anna’s work! I am curious as to whether it’s the alkalinity aspect or simply the increase in vegetable carbs that has made it a successful protocol; probably both! I have yet to read her book, but I have it on hold at the library. As a 26-year-old, some of the info won’t apply to me for a couple decades (hopefully!), but I’m sure it will be valuable. So glad to bump into someone who is familiar with her work!

    2. I’m curious what your non-above ground veggie carbs are coming from. Please share 🙂

      1. Hello there!

        Mostly they are from nuts (occasional), coconut milk, olives, berries, carrots, beets, dressings, chocolate (occasional), potato chips (very rare), yogurt (rare), kefir (occasional), and the incidentals found in eggs, jerky, etc. I will also use a 1/2 tsp. of sweetener (honey, maple syrup, or coconut sugar) in my coffee most mornings 🙂

  3. Hi Mark,
    Some things should be sorted out by people before they can positively say carbs or lack of carbs are causing a stressor. My own experience was that low carb dieting was always stressing and brought on already low energy and lots of depression. But one day I got real serious about not having anything with gluten, nuts, sugar, and chocolate and coffee. Well, in a couple weeks i was thinking better, no depression or mood swings, slept better. A total transformation without weight loss and not being ketosis either. But another really odd thing was that my handwriting (which has been terrible my whole life) was changed! Suddenly is was neat and legible! I had to wonder what happened to change my hand eye coordination? I guess by cutting out the gluten, the molds and lead from chocolate and nuts, having only the tiniest amount of weak coffee in the morning so that cuts out more mold and too high nickle exposure I must have severely cleaned out some problems that were affecting my brain, coordination, and appetite for years. I am now able to resist over eating carbs now and I never get depression or afternoon or lows and sadness. Who knew that a lifetime of bad handwriting was coming from my diet? That is just crazy. All my blues and moods could have been eliminated with eating differently. I have experimented with every health food trend and with supplements for years but never had results like this.
    Hope this helps out some struggling people out there.

    Thank you Mark,

  4. Very timely, as a 51 year old female trying to balance changing hormones. I can certainly attest to the tightrope of carbs, cravings etc and the sensitivity of lowering this macro. I seem to have a congenitall high sensitivity to stress hormones and cortisol is running the show creating insulin resistance, torso fat storage and disturbed sleep during peri-menopause.

    It seems I arrived with this wiring having been gestated by an emotionally volatile mother … some interesting research around about babies born to stressed mothers. Menopausal shifts result in higher cortisol so it’s a perfect storm for me.

    A continuation of your woman’s articles would be most welcome Mark. I’m currently looking at phosphatidylserine to supplement with to lower the cortisol effect, fingers crossed I guess.

  5. Useful post! I am still experimenting with carb amounts and timing.

  6. Hi Mark, thanks for this post, just what I’m starting to look at. I think auto/spell check have put in inculcate when you probably mean inoculate???

  7. When I first attempted a ketogenic diet years back, I found the lack of carbs incredibly stressful. I craved them constantly, had “carb flu”, had difficulty sleeping, etc. I gave up after 3 weeks, although I had lost weight (a success).
    However, at that time, I was going straight to a strict keto diet from a SAD diet. It was an extreme change. My body had been burning sugar for many, many years.
    More recently, I took a more gradual approach, cutting groups of carb sources out of my diet one by one, giving myself time to get used to incremental changes. This worked! Slowly my body learned to burn fats, and the cravings subsided. I think many people would find that a gradual move to keto can be more doable.
    Now I am largely keto (above-ground veg, meats, and dairy), with the occasional break for occasions like holidays and birthdays. And I find that if I allow myself just one indulgence at one moment on these occasions (eating one slice of cake, or having one pastry), I have little difficulty returning to my regimen. If I allow more than one moment of indulgence in the day, however, it is very easy to let it turn into a binge that lasts multiple days!
    The longer I stick with this diet, the easier it becomes. I think mental habit plays nearly as big a part as the famous gentling of the appetite that comes with keto.
    At this point in my life (I am 60 and post-menopausal), I appreciate the constant energy level and mental clarity that come with this dietary approach, as well as dozens of more subtle health benefits!
    As a weightlifter, I do want to say that I DON’T believe in “eating the carbs you earned”. I believe instead in a fasted workout, and no food for at least 1/2 hour afterward to give the biggest insulin sensitivity and human growth hormone benefits.

  8. This post was extremely helpful for me. I’ve been shifting to a ketogenic diet to help address gut/Candida issues post years of antibiotic treatment for neurological Lyme disease. I’ve always had a fairly clean diet and the last two years were even more so but fully cutting carbs has been kicking my butt this time around. I’m very hungry (which was a blessing at first because my appetite had been nonexistent), gaining weight, and having severe headaches. I’m way past any point of “keto flu”. While I’m not sure I know “what” is going on with my body, it was helpful to simply be reminded that carb restriction and ketosis isn’t as simple as a one size fits all formula. Thank you for helping me look at the bigger picture.

    1. I thought I read here that candida can feed on ketones? I’ve read that going sugar free, grain free, limited low glycemic fruits and low-carb but staying out of ketosis is very helpful.

      Also something that threw me off, start probiotics and fermented foods low and work your way up gradually… I knew the probiotics but think I overdid fermented foods.

      I am also trying to sort through candida issues. I was under the impression keto would just solve it but if there’s already an overgrowth it’s apparently more complicated.

      Good luck. I hope this helps.


  9. Haven’t reported in for a while – is this now Mark’s daily Keto ?

  10. My stress level is on very high!! Living without carbs has bn so hard. I’m ill all the time..Have my days when I fall off but get back on it. My mother tells me how sick I look n how I have aged.. 62 yrs old.

    1. Janice, what you’re doing doesn’t seem to be working for you. Are you living without ALL carbs? Do you eat fruit and vegetables? Aside from what your mother says, life is too short to be sick from the way you eat.

      You might not be getting enough calories. Try adding more healthful carbs to your diet. Eat some starchy veggies, like potatoes, roasted sweet potatoes or carrots, and maybe a little white or brown rice now and then. We are all individuals. Very low carb (or keto) doesn’t work well for everyone, women in particular.

    2. This does not sound right for you. Try a more moderate approach. It took me over a year to make the change from Primal to keto.

  11. Another excellent piece. Consistently amazed by how Mark finds time to produce these quality articles with all the projects he’s juggling.

  12. This definitely rings true for me. When I first started eating a Paleo-type diet, I hadn’t yet discovered Mark’s exercise recommendations and was still operating under a “more is better” mindset. I was doing intense, prolonged HIIT workouts multiple times per week and not really allowing enough recovery between sessions. I wasn’t intentionally eating low-carb, but it was definitely much lower carb than I had been eating. Initially I felt great, so I continued on with this pattern…but a few months down the road it caught up with me and I had all the classic “adrenal fatigue” type of symptoms. In that situation, while I was recovering, focusing on eating more carb-dense foods really helped my healing. Now that I feel like my energy/hormones are back in a good place, I’m contemplating going lower carb/Keto, mostly for the neurological benefits…but this time with a much more sustainable exercise pattern.

  13. Chris Kresser believes that people with hypothyroidism shouldn’t be on low-carb diets, because we need insulin to convert T4 to T3. My body seems to agree. Wonder if Mark has thoughts about this.

    1. I have read that as well and would be interested in more information.

  14. This is really helpful since I’m currently at loss on what should I follow with my food intake.