I feel a lot weaker with weightlifting since going ketogentic.... does anyone else have this experience? Are there hacks to get around this?

  • How long have you been on a ketogenic diet? Also, what kind of training are you doing? Are you trying to increase maximal strength, or are you more focused on hypertrophy? Or do you mean actual weightlifting (the classic lifts)?
    – Alex L
    Apr 8, 2016 at 4:39
  • Just simple traditional lifts.... All free weight compound lifts. What about MCT before lifting? Apr 8, 2016 at 13:02
  • 2
    Hacks to get around it? Try not eating a diet designed to put your body in an unnaturally deprived state.
    – JohnP
    Apr 8, 2016 at 15:52
  • Great chat guys. Most helpful thanks! I don't even lift, still I have this regular weak body feeling, heavy legs. Some say take even more salt. But GH top class reply make lots of sense to me. Love keto, love the foods, controlling my bloodsugar now, but.....energy too low man...
    – Carel
    Feb 12, 2020 at 18:10
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    Start eating more carbs. Keto is great for people trying to lose weight without a rigorous training program but those if us that lift 3 or more times a week need the carbohydrates for energy
    – Dude
    Feb 12, 2020 at 19:31

2 Answers 2


The immediate energy source for your muscles is adenosine triphosphate (ATP). When exerting force with a muscle it gets depleted (quickly) and when exhausted you fail to exert the same force. After 5 reps with the maximum weight you can do for 5 reps of some movement, a 6th rep fails. Fortunately, ATP can also get replenished relatively quickly. When being used, ATP is broken down and yields a different substance called adenosine diphosphate (ADP). Your body can create new ATP from the ADP. Of course, this requires it to perform some chemical actions. If the use of ATP chemically breaks it down and energy is released, it will take some energy to restore the ATP and make it available to the muscle again. Storing chemical energy in one place and then using it in another is essential in the energy transport throughout our body.

The creation of ATP from ADP occurs through metabolic pathways that are a bit too complicated to start describing here in full, but the gist of it is that the full pathway requires carbohydrate, fat and protein metabolism. Look up "citric acid cycle" and "oxidative phosphorylation" for more info.

So what does all of that mean for you? Here's where we get to glucose. Glucose is used later in the citric acid cycle and oxidative phosphorylation to yield ATP. It becomes oxidized, with as "waste" products CO2 (which you exhale) and water. Quite some water in your body is retained in the form of glucos, which is why you lose a lot of water weight on a keto diet. All of this means that glucose plays a key role in ATP formation, which your muscles need for producing force.

On a keto diet, you strongly restrict carbohydrate consumption and deplete the glucose (and its stored version glycogen) in your body. Indeed, such a depletion is essential to the diet because it prompts the body to switch to ketosis for obtaining energy from fats. So how is it gonna get its glucose? For that, it turns to gluconeogenesis. This is yet another metabolic pathway that generates glucose from non-carbohydrate sources. One of the ways this can occur is through breakdown of proteins and fats. Now, where the glycolysis pathway described earlier has a positive net yield of ATP, gluconeogenesis is going to consume some ATP. Also, glycolysis can occur directly in the muscle, while gluconeogenesis occurs mostly in the liver.

As you can imagine, this is not going to be quite as fast. When your muscles have a comfortable amount of glucose at their disposal they're happily gonna churn away on turning that ADP back into ATP. But when you're in ketosis, not only are you quite low on glucose throughout your tissues, making new glucose is gonna require gluconeogenesis. It's no wonder then that weightlifters tend to "carb load" before a heavy workout, and that you get exhausted faster on a keto diet when doing strength sports.

So you've asked for hacks. When looking at it logically, the only possibilities are:

  • Try to optimize ATP creation from ADP.
  • Try to optimize glucose available in the muscle without disrupting ketosis.
  • Find out if something in the glycolysis cycle can take the place of glucose.
  • Find out if there are other aspects of ATP creation that can be improved.

Unfortunately glycolysis is impossible without glucose. I'm afraid I'm running into the limits of my knowledge on the subject now, but here's some things you can try.

  • Take a creatine supplement. It improves the formation of ATP. Creatine is safe, inexpensive and easy to use. You'll just need powdered creatine monohydrate. Don't bother with anything else or anything more expensive.
  • Make sure you get enough protein. Too much could disrupt ketosis, but you do need it for gluconeogenesis and to make sure your body isn't gonna try to get it where it can (your muscles).

If you want my personal opinion, the ketogenic diet is very hard to get right combined with weightlifting and, to be frank, not worth it. I've done keto for some months and don't care to revisit it. It certainly worked for weight loss, but I found it very counterproductive for strength and muscle gain.

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    Update- I stopped doing the Keto diet. I was following it religiously for about 6 months. Then one night I ate tacos and drank beer. Went back into the gym and I was literally twice as strong. For powerlifting, Keto is pointless. I think for endurance or just weight loss it's fine. I found it hard to digest tons of fat to be honest. I felt good, but my memory also got sketchy. I think eating a balanced diet and a lot of intense exercise is what I need. Aug 29, 2017 at 1:35
  • @BrianTurner It's a conclusion me and probably many others eventually came to. Keto could be useful in the situation where you're trying to lose 1 or 2 kg of water weight in the span of a week, but it's not a diet I'd ever do long-term again.
    – G_H
    Aug 30, 2017 at 6:55
  • Except that I've been on a keto diet for over 5 years and I'll never go back to carbs. Your mileage may vary of course, and a keto diet isn't for everyone, but this answer is misleading at best and shows an incomplete understanding of how ketone bodies are substituted in the Krebs cycle for energy production. My strength, endurance, and overall health has never been better. If fat is such a poor energy source, then why did our bodies evolve to store weeks worth of it in a handy spare tire around our waists?
    – PJNoes
    Feb 13, 2020 at 23:13
  • @PJNoes Ask yourself why our bodies give priority to the use of glucose rather than fat and tend to keep the latter around as a ration for when there's inadequate calorie intake. Fat is not a poor energy source, it's just not as quick in providing energy as glucose is.
    – G_H
    Feb 17, 2020 at 9:29

It's quite normal to feel "weak" on a ketogenic diet, at least compared to one with a normal amount of carbs in it.

You need energy from either fat or carbs. Fat is stored for longer and the energy "lasts" longer(but spikes less), whereas carbs spike quite fast and drop off more steeply.

From the sound of it, perhaps you aren't getting enough good fats in your diet? What I used to do when I did keto + running was to eat a good handful of nuts about an hour before I went out to run. It helped greatly. Same thing with certain fruits that aren't that bad in carbs(like a pear or an apple) to also get the spike from fruitsugar helped me.

  • Starting taking MCT oil before lifting, made a huge difference. Apr 12, 2016 at 4:17

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