Dear Mark: Cold Weather Carb Cravings, Muscle Loss in the Military, and Pain During Exercise

Cold WeatherFor today’s edition of Dear Mark, we’ve got a two-parter. First, I cover why our desire for carbohydrates might increase in cold weather (hint: it’s probably all the shivering our muscles do in an attempt to stave off the chill). Second, I discuss why a military man might be losing muscle mass when out in the field, despite (or, perhaps, because of) all the hard physical work he’s doing. Even if you’re not military, the answer will likely still be helpful. And after that, Carrie lends a bit of sage advice to a reader who ends up with debilitating pain in her thighs every time she does high intensity plyometrics. The answer may not be what she had hoped for, but it’s probably the right one.

Let’s go:

Hi Mark,

I am currently working a job where I spend every other week living outside leading backpacking trips. In the winter, temperatures will be in the 20s or 30s during the day and colder at night. I’ve noticed the last couple weeks that as the weather gets progressively colder, I’ve started craving carbs more and more. I was wondering if I need more carbs to help keep my body warm if I’m living for 8 days at a time in that cold of weather?



It could be a couple things.

The first thing I would guess is that you’re simply burning more fuel, particularly glycogen, acclimating to the colder temperatures. For example, shivering is used to generate heat and maintain body temperature in the face of cold exposure, and it utilizes a variety of fuel substrates, including lipids, glycogen, and to a much less extent, amino acids. But here’s the thing: even if you’re burning 50% lipids and 40% carbs, you have plenty of body fat to draw upon before turning to dietary sources – even the very lean have pounds and pounds of pure animal fat at their disposal. You’re not going to crave fat, necessarily, because you don’t need to eat any to replenish your stores.

What about glycogen? Glycogen stores are smaller, somewhere in the 400-500 gram range depending on the amount of lean mass you carry. Big muscular men will have larger glycogen stores (but they’ll also use more moving that mass through space). Women tend to have less lean mass and therefore smaller glycogen stores. Burning through glycogen increases the dietary desire for carbohydrate because dietary carbohydrate is the quickest way to replenish glycogen. You can generate it from protein (either through the diet or taken from your own lean mass) through gluconeogenesis, but the body prefers to get it directly. Fewer steps that way (plus, protein’s better used for other things). So, if you’re spending eight days outdoors where the temperature never gets much higher than freezing, you’ll be burning through a lot of glycogen – and craving carbs – simply from all the shivering you do. Throw in some activity (backpacking all day) on top of that and you’ve got a recipe for carb cravings.

You may also be experiencing a natural seasonal variation in hunger. Some researchers have even suggested that seasonal affective disorder, which as you know occurs during winter when the days are short and sun is scarce, might be an evolutionary adaptation that favors energy storage in otherwise inhospitable conditions. I can see that. SAD makes you sad and kind of gloomy, so you’re less likely to put yourself out there and take risks. It reduces your desire to exercise, which conserves energy. It lowers libido. It’s even associated with carb cravings. Nowadays, in our energy replete, already sedentary, carb inundated society, SAD has an overall negative impact on health. It’s not fun (or helpful) to be depressed, crave junk food, feel lazy, or have no libido. But thousands of years ago, it might have improved survival by keeping people alive, conserving energy, increasing energy stores, and limiting procreation in an energy-poor environment (which can have negative epigenetic effects on the fetus).

Under your circumstances, I think additional carbs may be warranted. Eat to your appetite.

My husband is in the military; when he goes to the field (any amount of time), he doesn’t eat a lot and does a lot of physical work. He comes back with way less muscle, and maybe a little fat loss but virtually the same. Why? Shouldn’t his muscles be using the fat instead? Can you clear this up? Thanks 🙂


This is a textbook example of tons of physical activity coupled with low calorie intake begetting chronic elevations in cortisol. Let’s unpack this a bit.

Your husband is highly active in a demanding environment without eating enough food. If he’s wearing kit, that can add fifty, sixty pounds to the equation. He’s essentially on a chronic low-calorie diet, which is known to increase cortisol levels. Now, cortisol isn’t all bad. That burst of cortisol we secrete first thing in the morning can actually help mobilize fat stores. The problem is when cortisol is chronically elevated, as with formal dieting or doing lots of physical work without eating much. That’s when abdominal and visceral fat can accumulate and muscle begins to atrophy. The relationship between chronic cortisol and skeletal muscle is well-established. Older folks with the highest cortisol levels tend to have weaker grips than folks with normal cortisol, and those with high cortisol-to-testosterone ratios have reduced muscle strength.

I’m fairly certain this is the culprit.

It comes down, as it always does, to the question of acute versus chronic stress. A modest calorie deficit and exercise several times a week with generous refeeds is a good way to lose body fat. Your body won’t “think” you’re starving. It won’t buckle down and start making tough choices regarding which tissues to break down for fuel. Maintaining a severe calorie deficit and excessive exercise regimen for extended periods of time signals famine. Muscle is metabolically demanding. It’s awesome and useful and physically attractive, but it requires a lot of nutrients to maintain. If nutrients aren’t coming in for the foreseeable future – if your body thinks you’re experiencing famine – muscle will wane.

Muscle can’t be built (or even maintained) without the necessary building blocks: calories, fat (for hormone production), and protein. Your husband isn’t getting enough, and he’s burning through what little he does eat. Since the physical activity is probably nonnegotiable, his best bet is to cram as much food down his gullet as possible. This may mean eating less-than-Primal fare. Given the situation, that’s okay.

Good luck!

Dear Carrie: Pain During Exercise

My thighs (quads) kill me when I perform certain exercises such as squatting down, jumping up explosively, landing, and immediately repeating. Or when I do burpees, or do an exercise where I place my palms on the floor, invert myself into an upside-down V shape, and hop my legs from side to side, lifting my lower body with the core. Tuck jumps hurt. Even if I bend down to touch the floor, jump high up, and then land and bend down again on the other side and repeat… all of these exercises very quickly build pain in my quads that is excruciating to me and forces me to stop. When I do, the pain fades away within a minute.

Is this an overload of my muscles or what? I can’t seem to fully understand whether this is natural, if I did anything to cause it, if it will ever go away (I am praying it will). The seemingly constant and lurking presence of this possibility when I engage in such plyometrics (which I really really want to do) weighs down on my self-confidence and faith in my body.

I’d love for your feedback and advice with this nagging problem. =)

Thank you so much!


You have to slow down. Way, way down. It sounds like you may be trying to do too much too fast (literally; your exercise choices are intense and high speed). The excruciating pain is a warning sign that you’re risking serious damage to your body. That the pain disappears almost immediately is a “thank you” message meant to convince you to slow down the exercise. It’s best to listen to your body when it’s giving you such clear signals, or you risk doing some long term damage.

I’ve been there as well. I understand the urge to push through the pain at almost any cost. For years I had to get in a hard workout every day (usually some form of chronic cardio) or else I’d feel like the day wasn’t complete. Mark, as you probably know, used to be like this too, and maybe that’s part of the reason we got along so well: we bonded over our mutual addiction to exercise. The only way I got over it was to just stop doing the things that took a real toll on my body. I stopped running. I stopped going to the gym every day. I started hiking a lot and making my intense workouts much shorter (and by extension more intense and less frequent) than before. And it was hard and I worried I was going to gain weight and lose my fitness level. I stuck with it, and when those things didn’t come to pass and my fitness and body improved if anything, I was over it for good (at least so far!).

When I look at the exercises you describe, I see a lot of redundancy. Jumping squats, burpees, upside down hopping Vs, tuck jumps, and that other exercise that involves bending over and jumping – they’re all very quad dominant and they all involve a ton of force applied to very specific tissues. Namely, your thighs. There’s some core and some other stuff being worked, but it’s a lot of jumping and landing. That will add up over time and it seems like it is adding up already. When you get back into intense movements, stick to one per workout. Don’t ramp up and throw all those exercises at your body in one workout. You’re probably still growing, and even if you aren’t and you are a full grown adult, that would still be a heavy load for your legs.

Honestly, it comes down to the pain. If the pain is there, you’re doing something wrong and you need to rest.

So here’s what I would suggest:

  • Stop the calisthenics for the foreseeable future.
  • Use a foam roller before you train to help massage and release tight muscles. I use Trigger Point Performance Rollers by
  • Try a weekly yoga class for increased flexibility, increased muscle strength and tone and protection from injury. (I may do 2-4 classes a week.)
  • So you don’t go crazy from inactivity, walk or hike a couple miles a day. Maybe even a couple more.
  • After a weeklong rest, start some easy, slow strength training. Bodyweight movements are fine. Dumbbells or barbells too. Stick to compound, full-body movements. Twice a week to start.
  • If you ever do go back to calisthenics, try box jumps. You still get the advantage of jumping as high as you can but you land on a box at the peak of your jump. This reduces the impact to your legs and joints. It’s easy to overdo box jumps, though, so be careful. Think quality and form over quantity. Note that it takes about 120 hours for your body to fully recover from box jumps (probably even longer for other, more stressful forms of calisthenics).
  • Sprints once a week. I find sprints have been by far the most effective in toning my butt and thighs, sometimes I’ll do them twice a week. Sprint uphill to reduce the impact.
  • Play! Find something you love doing, like a sport or any other physical activity that doesn’t involve repeating the same motion over and over again. (I love taking long beach walks and hikes with Mark!)
  • If the pain persists, see a medical professional and/or physical therapist.

Good luck and be sure to write in if you need anything else!

Well, that’s it for this week, folks. Got any questions for me and Carrie? Ask away in the comment board, and we’ll try to answer them in future blog posts. 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.

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35 thoughts on “Dear Mark: Cold Weather Carb Cravings, Muscle Loss in the Military, and Pain During Exercise”

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  1. Constant shivering is a symptom of hypothermia. An outdoors person tries not to get to that point. Outdoors people recommend eating frequently small amounts of nuts, dried fruit, candy to stay warm. I think the candy can be overdone. Many outdoors people recommend high intakes of carbs. I find I can get away with nuts and dried fruit with a little chocolate while xc skiing or snowshoeing. Also sipping water frequently keeps you warm and may even quell the carb cravings.

  2. I personally don’t think pain is ever a good thing. Soreness (the feeling of progress), now that’s a different thing. Back up and slow down. Learn the art of play!

    1. +1

      Yeah, acute, stabbing pain is never, ever something to push through.

    2. I agree. I like the idea promoted in yoga which is to be consciously aware of your whole body while exercising, and only going to your limit and not beyond. Works well and makes sense for me. Progress can me made little by little each day.

  3. I’m Canadian, having lived in cold temps for extended periods of time (-20C average) I can say the best way to stay warm is not carbs, it’s fat.

    I usually make myself a thermos of gravy, yes THAT gravy, and I usually make it with bone broth/drippings/left over meat all blended together in a nice hot drink.

    Once you get over the taste (it’s not coffee or hot chocolate after all) you’ll feel it drive warmth right to your toes.

    Also like Shalimar noted, by the time you start shivering you’re already in trouble. Dress in many loose layers that you can add/remove simply throughout the day depending on your activity level etc…

    1. That has to be the most Canadian thing I’ve heard in a year. Love it.

      After observing the diet of some folks in Montreal during cold weather, I have to concur. Duck fat, butter, lard, and fatty red meat seem to dominate. After trying the same myself over a cold South Dakota winter or two, I will always eat like a Canadian in winter… minus the copious amounts of alcohol.

      1. Butter. I had a decade there where I got in a winter backpacking trip every year. I found my body automatically upped its thermogenesis after 24 hours in the cold. Fat, fat and more fat is what I found kept me warm, energetic, and full.

        Don’t konw about carb cravings though.

        1. Staying hydrated is also a super important factor in staying warm Fatty, salty broth, lots of hot water and herbal teas, drink plenty! Proper gear is essential, too, just like these guys say, layer up, layer down, never let yourself get too cold or hot.

  4. Yeah, I don’t know why Mark jumped right into shivering as the source of the carb cravings. Anyone with any outdoor leadership experience knows better than to get to the point of shivering. As they say, there is no bad weather, only bad clothing.

    That gravy idea sounds like a winner. I imagine a tropical gravy such as a coconut curry in a thermos might also work, you know, for a little variety.

    As for the 2nd question with the husband who goes out and exerts himself without eating much, my partner is exactly like that. In fact, he looks forward to several trips a year where he can strap on his pack and lose his appetite for a few days. He thinks it helps him control his weight. But it really doesn’t because the weight doesn’t stay off and it certainly doesn’t make him stronger or more muscular. But he’s not into any of this primal stuff so I can’t really convince him otherwise.

    I wonder if regular bouts of this kind of temporary “famine” is part of why he has so many aches and pains, too. I mean, if your method of weight control and exercise is basically to break down the body, wouldn’t that follow?

    1. In Southern California, they start shivering at anything below room temperature. 😉

  5. Carb craving in the winter. Hmmm? I wonder if the Inuits, Eskimos, and Samis (prior to adopting modern foods into their diets) ever had carb cravings in cold weather? Probably not since their carb intake was extremely limited. They were probably ketogenic, all of them.

  6. I was hoping for a chance to point out that Derrick Rose is again hurt and heals extremely slowly. Couldn’t have anything to do with his well documented candy diet could it?

  7. I would also think fat would help in colder weather as the Inuits ate basically no carbs and did just fine with lots of seal (mhmm blubber). I too have lots of carb cravings in the winter and didn’t think of increasing my fat! Don’t think I’ll be going for seal though…

  8. Im a big skier and I think its true about both carbs and fat and cold weather. The attempt to stay warm brings on the desire for carbs- (hot choclate anyone?), but I find that if I have enough fat in my meal after skiing ( big steak, anyone:) I’m usually better off. I for one love winter- go snow!!

  9. It won’t kill the guy to have more carbs if he’s outside in the cold, moving all day.. If you have carb cravings, try eating more carbs.. That being said, it’s easy to overeat during the winter season. At least it feels to me that my appetite increases during the winter months and is more subdued during summer. Here in Stockholm it gets dark at 3pm during winter. This and the cold weather make people move less and stay inside and eat heavy, warming food. During the summer, it’s more natural to be outside, moving and having fun, eating lighter meals. California dreaming..

  10. I can sympathize with desire to push oneself to one’s limit. For the last several years, at the times when I kept to more frequent trips to the gym, I would tell myself I was only going to do exercises A, B, & C and do 10-20 minutes cardio. Usually, I did a good job sticking with my goal for cardio, but I’d always start throwing in more and more exercises after the cardio (D, E, F, etc) all in a desire to push myself. I found myself leaving the gym quite tired some of those times and occasionally found I would lose my desire to return to the gym in a “regularly scheduled” manner.

    The closer I get to returning to more frequent workouts (few times a week), the more I am realizing how much it benefits the body to stick to only a few exercises +/- cardio (excluding a few minutes to warm up, and a few minutes to cool down after more intense weight sessions).

    Hearing Carrie mention how much even just a couple sprints a week helped her to ‘tone the tush’ are more reinforcement of the briefer, but regular workouts that Mark has also advocated for quite some time.

    Challenge accepted!!

  11. Hi there Mark and Carrie. This is Helena – the now very grateful reader who you responded to in this post.

    I wasn’t expecting you guys to do me such an honor by including my question in a “Dear Mark”. I was just hoping for an answer… and you, Mark and Carrie, gave me a great answer in a great way. Thank you so much 🙂

    I’ll take Carrie’s advice and be sure to call back if I have any other questions. I know you guys are extremely busy; I just wanted to comment here to thank you for maintaining this site so well, really updating it with meaningful and relevant content often, and helping us readers live like Grok. =)

  12. If I increase my caloric intake, I find I can withstand the cold a little better. And it doesn’t necessarily matter which macronutrient predominates.

    This probably isn’t helpful to Briana, but for those who are subjected to cold temperatures only periodically, forced cold exposure on a routine basis may help. For example, I regularly take cold showers and polar plunge in icy waters, and find that it increases my body’s tolerance to cold temperatures.

    Great post, Mark!

  13. I’ve been thinking about something for a while. I’m trying to learn singing, and I noticed that last summer when I was eating primal, and lots of butter and coconut oil, my voice was coming out smoother. But since I started college this fall I’ve been really bad at my eating, like most days I’ll just have a coffee and something grain-based, no vegetables and hardly any fat, or I’ll just not eat anything for days, and my voice has been cracking a lot. What are your thoughts on this? I’m especially wondering if eating high fat helps the vocal cords or whatever it is that controls your voice be smoother?

  14. When reading Helena’s question about her leg pain, it sounded to me more like a possible medical condition rather than simply overtraining. I didn’t take away that intense leg work was all she doing, but that when she did it, it was very painful. There is a condition called Compartment Syndrome that presents with intense pain upon physical exertion that abates quickly when the activity is stopped. I’ve heard of this more the lower legs but assume it could also be present in the thighs. Its due to fascial compartments in the legs becoming swollen and restricting blood flow upon exertion. I would advise that if she doesn’t find that rest and gradual increase of activity works, that perhaps a visit to the doctor might be in order. Thanks!

    1. Wow, what a helpful post 🙂 Thank you for this new information. I’ll be sure to check it out.

  15. I think it is mainly about the cold weather being a serious bummer. With the colder weather means less fresh air and less sunshine, and even perhaps less time spent conversing with friends.

    We make up for this by looking for comfort in other areas. Unfortunately, for many of us, we have been trained throughout our lifetimes to find comfort in high-carby snacks.

  16. Look up the Endurance. It was an Antarctic exploration vessel, which got stuck in the ice near the South Pole. In the book I read about it, the men’s diary entries reference frequentt eating of seals, blubber and all. They had to survive for a year, If I remember correctly, treked an inordinate distance whilst hauling supplies, and (If memory serves) they all survived.
    There were NO carbohydrates for them to eat.

  17. Hey, Helena!

    Way back when, I would work out three times a week, and although the weightlifting wasn’t a problem, any form of aerobic exercise was. Especially the bike. I hated it. I was moving plenty of air and wasn’t out of breath or even tired, but it killed my legs. And there was this sense of impending doom: I couldn’t say why, but I hated every minute and felt as if something, God knows what, really bad was going to happen if I didn’t stop. Not just slow down, stop. Little did I know that I was in the early stages of Hashimoto’s thyroiditis. It wasn’t until a couple of years later that I began to put on weight that I couldn’t drop, and feel fatigued and achy, and eventually develop tremors and phantom sensations in my legs.

    Get your thyroid checked and keep an eye on it regularly. Don’t obsess about it, but know that it can make you feel distress from activities you feel perfectly accustomed to otherwise.

    1. Yeah, the psychological and deeper medical aspects of it sure are confusing. :/

      I hope that since then you’ve managed the pain and conquered it too. Thank you for sharing. 🙂

  18. As someone who suffered on and off with crippling back pain for a few years, I highly suggest taking a look at “Healing Back Pain: The Mind Body Connection” by Dr. John E. Sarno.

    I was very close to getting surgery when I saw the book on my shelf. A family member had given it to me about a year prior but I didn’t bother reading it. In a last ditch effort to avoid surgery I started reading and applying. I was amazed by how rapidly things improved. I “relapsed” a few times and continued the practice. Those few years of back pain are now a distant memory — on Monday I easily deadlifted 290#’s for a set of 5.

    If it applies to you and you do the work the results are life changing.