The keto diet: Happy muscles running on fat

Over the last few weeks of my pretty active life — biking to and from work, hiking hills with friends, kayaking, paddle boarding, competing in dragonboat races, and even just working out at my local gym — I’ve noticed something exciting: my muscles feel just great.
In fact, at age 59, my muscles feel and perform better now, in every sphere of my life, than they ever did when I was 20, 30 or 40.
They are stronger. They don’t hurt as much when I am working out; they don’t fatigue as easily or complain under strain as much. And after a hard workout, they don’t feel as sore as they used to the next day.
I can come to only one conclusion: My muscles run so much better on fat than they ever did on glucose.
The difference really struck me this last month, after slipping off my ketogenic diet while at the family cottage. I’ve been solidly in ketosis for almost two years now, ever since a pre-diabetes scare in the fall of 2015 converted me to the low-carb keto diet. In the post I wrote about that cottage slip, I joked that one impact of falling off the keto wagon was that my reaction time and performance in our cottage spike ball tournaments significantly declined.
But it wasn’t really a joke. My performance did decline. I’m proud to say when I first arrived at the cottage I was a keto-adapted fat burner and I won the first highly competitive spike ball tournament with my niece’s partner. “Aunt Anne you rock!” the young nieces and nephews (all of whom I beat) had high-fived me. By the end of the week, same partner but now eating a high-carb diet, I performed dismally – slow and sluggish. Where we were unbeatable a mere five days earlier, we were unwinnable now. And it was all me.
That poorer physical performance while still out of ketosis really hit me the first day I got home. I ride the same route to work every day, but on my return, the hills were suddenly harder. My leg muscles hurt and felt fatigued on the inclines — rapidly, within seconds. My lungs were fine but my legs felt wimpy. I’d only been gone 10 days. I’d remained highly active. The only thing that had changed was my diet, adding back in enough carbs to take me out of ketosis.
An insight about muscles on keto
That night, I had a revelation as I was carrying a big load of clean laundry up the three flights of stairs in our old house. My legs ached and felt extraordinarily heavy by the top floor. Suddenly I recalled that for many years, pre-keto- diet, that weird leaden ache had been routine doing that regular chore. Back then I had concluded that, along with the ardent desire to do a renovation to move the laundry from the basement to the upper floor, I needed to work out more and get more fit.
But here is the thing: during those years I worked out all the time and that leaden leg feeling never went away, no matter how many leg presses and squats I did. I saw personal trainers, tried different workout routines. I would push through the muscle fatigue and ache and wonder, ‘will this feeling ever go away when I get fit enough?’ I was no couch potato either. I’d been a competitive athlete in my teens and 20s, and highly active all my life.
That odd achy leaden muscle feeling got so bad during two very stressful periods of my life — and included fatigue, weakness, numbness, fasciculations (muscle twitching) and cramping — that I was referred to neurologists to be investigated for multiple sclerosis or other neurodegenerative conditions, which fortunately I did not have. I realize now, however, that during both those times of high stress, carbs in the form of pasta and potatoes had been my daily comfort foods. Was it all related?
Carrying that laundry load I suddenly knew: it must be. I hadn’t felt that leaden heavy ache for two years in ketosis in any of my activities. My muscles had felt fantastic.
It sent me to the medical literature to inquire: Do women with polycystic ovary syndrome (which I was diagnosed with at age 19) have any evidence of reduced muscle function, muscle weakness or fatigue?
The search rewarded me with multiple articles and studies — more than a dozen — how skeletal muscle insulin resistance of PCOS causes impaired insulin action on glucose uptake, impaired mitochondrial function and increased oxidative stress.
One 2010 article, entitled Skeletal Muscle Insulin Resistance in Endocrine Disease, had this revealing summary: “In PCOS, muscle insulin resistance has been associated with abnormal phosphorylation of insulin-signaling proteins, altered muscle fiber composition, reduced transcapillary insulin delivery, decreased glycogen synthesis, and impaired mitochondrial oxidative metabolism.”
It all made sense. For years no matter how much I trained or worked out, my muscles always complained. But when I switched my fuel to fat, they hummed along happy and strong.
Earlier this year I wrote a summary for Diet Doctor “Eight reasons to adopt a low carb keto diet for PCOS“. Now I would add a ninth, at least for me: Because my muscles feel so much better in ketosis.
But I wonder: have other people experienced the same phenomenon? I’d love to hear about it. Feel free to leave a comment below.
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fruit, especially organic raisins aids performance and expedites recovery. My experience is that slower endurance based excercise responds just fine to fat burning alone. I would be interested in any other suggestions re more intense physical exercise.
Somewhere on this site I saw an interview with Prof Noakes where he talked about a possible need for small amounts of carbs to top up glycogen reserves for some athletes to achieve bursts of speed. But do you think I can find it now?? Maybe searching on his name here and more broadly will bring you better luck than me in finding it!
Catherine
I think there is a difference between athletic and active. Most Canadians carb load like they are competing in the Olympics and they aren’t exercising at all.
I find my muscles are stronger on keto and also more defined. Whether that’s because of loss of body fat I’m not sure. I do not get severe muscle pain or fatigue but I have also changed my exercise regimen as I age for less long distance endurance work and shorter daily exercise that includes stress reducing activity as well as weight lifting.
I have seen patients reduce pain in their joints and muscles and reduce muscle fatigue and general fatigue with LCHF whole foods eating. I have seen people get off chronic narcotic analgesic after dietary change. And I have helped patients to get pregnant with keto eating (when they weren’t able to before).
Ultimately it has to be what feels right for each person. But it definitely works for me (in the post meno modifications).
NP Samantha
You are such an inspiration! Am forwarding your article to a bunch of people. Keep up the good work!
Mel
You may have to experiment to find where you feel your best. Consuming 15 grams is very low -- you may not need to be that low to still achieve the results you want. You can lose weight and have reduced inflammation on moderate low carb or with occasional "carb ups" - having small amounts of healthy carbs - like orange sections or apple before exercise.
I hope that helps.
supplements I'm full of strength and no sore muscles the following day. Unfortunately no one I talk to about it believes it's good for me they have a ''yeah but'' to everything I say good about the diet.
I do find I will get bad muscle cramps (early hours of the morning) if I do not have enough sodium. In my 40 years of avoiding fat, I also tended to not add much salt to my food, so now I find I definitely have to up my salt content.
Magnesium could also be an issue. Drs. Stephen Phinney and Jeff Volek, in their book "The Art and Science of Low Carbohydrate Performance" have a great section on muscles and magnesium , saying when magnesium is low "muscles get twitchy" - cramp, fatigue, twitch, ache. The section is page 83 to 85 in their book and they have an intensive magnesium supplementation protocol that takes 20 days, using slow release magnesium (trade names: Slow-Mag, Mag-64, or Mag-Delay.).
I don't know where you are, but those formulations are available in the US, but not in Canada. I don't know about other locations. I am in Canada so have asked a friend to send me some so I can do their protocol. They say take 3 slow release magnesium a day for 20 days; if cramps/ muscle symptoms return after you stop, take two a day in perpetuity. Only contraindication to doing it is if you have chronic kidney disease or kidney failure.
I have not done it yet, but in the meantime while i wait for Slow-Mag to arrive, I am currently adding electrolyte drops to my water and that seems to reduce my night time cramping, along with being well hydrated and getting enough salt. It might help for fasiculations and fatigue, too. Since you are under medical care to investigate this, perhaps ask your doctor whether supplementing with magnesium might help? (Phinney and Volek do note: "Magnesium resides in our cells. There is very little of it in our serum, so blood tests for this mineral cannot tell us if we are okay or not. As a result, doctors who rely on blood tests are generally clueless about magnesium.")
A question though -- did you try adding back in some healthy higher carbs, like sweet potatoes, beets, beans, baked potatoes? Did you notice an improvement in symptoms coming out of ketosis with higher carbs?
Good luck sorting this through as I am sure it has been a concerning and challenging time. - Anne Mullens
They have determined that I am hypoglycemic...not sure how that ties to all this.
If you're referring to carb cycling, it's not something we recommend. The idea is to keep blood sugars and insulin levels stable, and carb cycling is counterproductive to that goal.
A single molecule of ATP contains 10 carbon, 16 hydrogen, 5 nitrogen, 13 oxygen and 3 phosphorus atoms. The formula of ATP is C10H16N5O13P3. Three phosphate groups are attached to the assembly of adenosine. Here is where need ---------------Phosphate.
ATP (adenosine triphosphate), the main source of energy in cells, must bind to a magnesium ion in order to be biologically active. ---------------need MAGNESIUM here as binder. Magnesium ions regulate over 300 biochemical reactions in the body
Salt is composed of sodium ( NA) and chloride( Cl), which are two electrolytes that help maintain fluid balance and the transmission of nerve impulses. When depleted in the body, sodium must be replaced in order to maintain intracellular osmolarity, nerve conduction, muscle contraction and normal renal function.
The body needs to have a 7 pH which is neutral or water (7 pH) if too much base or to much acid will make body not work well.
Brain needs amino acids. All of these are found in Beef. Brain clarity when start eating beef and eggs. Other lesser forms also which are not as good as beef for uptake. Real beef, not processed.
The Vitamin B which is B1-B12 is very important for energy. Vitamin C for health.
.uc.edu/content/dam/uc/ce/docs/OLLI/Page Content/CHEMISTRY OF ATOMS AND MOLECULES OF OUR BODY.pdf.......................This is a very good power point on more information.
Krebs cycle in the mitochondria is our basic life force. Need all of above to make it work and some others not mentioned.
Try these and see if it helps. Do not go overboard. See doctor to help as needed. Will get rid of most headaches and some muscle pain after workout.
Tells you why need Potassium, Salt which contains NA and Cl, Calcium Ca, Phosphorus P, Magnesium Mg and Water. If do not keep a neutral 7pH in body will suffer from side effects. Too acidic or basic will cause symptoms. See the slide show from UC.