Weightlifting while fasting

#1

Hi folks! I’m been reading the forums for a couple of weeks and finally decided to create an account to join the community. Ask a few questions and hopefully be able to contribute in a meaningful way.

I’ll start off with a question…

I’m fat adapted based on all of the definitions that I’ve read online. I workout with weights 2-3 times and week and have just started doing cardio on non-weight days.

From what I’ve read, weights are best done in a fasted state (when IFing) just before having a meal.

What about during a longer fast, say 48 hours? Is it still safe to do strength training but not consume anything other than non-carb liquids for the following 24 hours? I want to be sure that I’m not doing myself more harm then good.

(Little Miss Scare-All) #2

Well, I fasted for over 48 hours last week and still made it to and through my powerlifting lite class which is 1hr long, 3x a week. Id say itd be fine as long as its not habitual, because refueling and such after lifting is a splendid idea.

(KetoQ) #3

Given my experience, its fine to lift fasted. If you are going to weight train fasted, I suggest a 24 hour fast, then eat your protein soon after your workout. Again, in my experience, protein post weight training is a major muscle builder. It is a huge factor for me.

Given my experience with IF and working out, 48 hours is a long time not to eat then train. Furthermore, I wouldn’t say weights are best done in a fasted state, because you may need extra energy (muscle glycogen) to do your lifts, even if you are fat adapted.

I did a number of 60-70 hour fasts during the summer of 2018 and finished it off with a 6 mile walk before my first meal. I often felt very weak and once or twice felt a bit light headed where I thought I may pass out. That could have been dehydration. It could have been heat exhaustion. It could have been low levels of something else. But when I did the walk fed, I never had that weakness or light headedness.

Good luck.

#4

Yes you can - just be prepared for the earlier fatiguing and wimpy feeling - it’s very effective though despite that.

If you do super slow/slow burn/Body By Science HIT strength training it’s both anaerobic and aerobic, so you don’t have to do any extra cardio and it saves a lot of time for other fun things/family life away from the gym room etc.

(charlie3) #5

My opinion, overall training status is more important than the last time you ate something. If you are just getting into aerobic work check out the Meffatone Method, aka low heart rate training. Short course, use a heart rate monitor and keep heart rate strictly below 180 - Age which is supposed to be below your aerobic threshold. You are aiming to teach the body to burn fat instead of glucose for aerobic actiity. I’ve been training this way for a while. It takes more time but I believe it preserves anaerobic energy for lifting. I do it on a vintage airdyne, not running.

(Windmill Tilter) #6

I did 84 hour fasts prior to every weightlifting workout for four months last winter/spring. I increased the weight on all of my lifts significantly during that time period. I always broke the fast an hour after the workout though.

It’s perfectly safe to lift mid-fast. It’s probably not optimal for hypertrophy to do so however…

(Full Metal KETO AF) #7

@Brenda Zorn has done some 5 day fasts with heavy weight training and a DEXA scan going in and out with surprising results. I don’t have any link but hopefully she will chime in. She’s a very busy woman. Sometimes she is around a lot and then gets busy and we don’t see her for a bit. :cowboy_hat_face:

(Bob M) #8

84 hours is a lot. I still do some 33 hour or so fasts then hit the gym. I used to work out during my longer fasts, but have ceased doing so.

#9

It’s probably individual. 48 hours isn’t very long and weightlifting isn’t some extreme activity (though it depends on the weights but still, it doesn’t need as much energy as some strenuous and way longer activity) so I am sure it’s fine for many. I prefer 24 hours but even if I would have no significant problems at 48 hours, I am a weak almost-beginner with baby weights who doesn’t even care about small performance boosts, it’s obviously different if someone uses heavy weights and wants to do their absolute best. While some people prefers eating and even a signficiant amount of carbs before a workout, food and carbs just enervate me, I need a well-fasted state for weightlifting (but it was below 24 hours in my case, just perfect), it’s another individual factor. I probably would try and see as it may work just fine and may not, it depends on the person and circumstances. I would put my workout a few hours before my meal as I always ate afterwards this far, it sounds logical and more importantly, I always felt the need. I don’t have this with walking, that’s not strenous enough, I walked for hours without problems at 100 hours but weighlifting or cycling uphill is different, I just feel the need to eat afterwards if my last meal was long ago.

#10

Thank you all so much for your thoughtful responses. I really appreciate it!

To summarize, I won’t be doing any damage if weightlifting in a fasted state and continue to fast for another 24+ hours but it is not optimal from a muscle building perspective.

After lifting I didn’t feel weaker, in fact I was able to do more weight on one of my final sets. No lightheadedness , so I figure if my body isn’t tell me to eat something that I should be fine continuing a fast.

It might help to state that my main objective is improve my BMI by losing body fat (primary) and from gaining muscle mass (secondary).

Thanks all!

(Little Miss Scare-All) #11

Word. Me, too. These are splendid goals. :grin:

(8 year Ketogenic Veteran) #12

TL;DR
busy I am.
Fasting creates a release of HGH, human growth hormone that has allowed me to gain incredible lean mass by only lifting twice a week, 1.5 hours each time. I lift very heavy with low reps. I lift any day of a fast including during a 9 and 10 day. I ALWAYS lift fasted at least 15 hours. Fasting is muscle preserving and eating extra protein does not build muscle. These are my nuggets of wisdom, that and get a DEXA scan if you possibly can. Do another in 4 months to track what happens. I have done this often. I am 5’7" and have a lean mass of 140 pounds. Most women my height and age have a lean mass of 85 to 95 pounds. I am 56 years old.

Dave Asprey interview, 1/2/20: Ageing Boils Down To The Mitochondria, Keto, Sleep
#13

Thank you very much for the information. It gives me confidence that I’m not doing something wrong, quite the opposite. I’ve only done a max fast of 68 hours so it gives me something to strive for.
Thanks!

(Henrietta Tubbola) #14

Love this :point_up_2:it confirms my studies too.

I’m currently on day 8 of an extended water fast, just restarted lifting and running and I feel GREAT! :slightly_smiling_face:

#16

I completed a 7 day extended water fast and was also feeling great!

Interesting to note, when I worked out on day 3 and was able to lift more then I did prior to beginning the fast (arms/back).

But on day 5 when I was working on shoulders and chest, I struggled. Either did the same as the previous week or I did less weight or reps. It was a little disheartening. Thoughts of “did I lose muscle since I didn’t work out this muscle group since I started fasting?” went through my head.

I did some reading I think it was because I wasn’t properly hydrated. I was reading that a little salt (1/4 tsp) with a full glass of water before a workout would have helped ensure that I was properly hydrated.

After the fast I did legs and abs and I had no issues. I didn’t do more but I certainly didn’t do less.

I think I can conclude that it is indeed safe to workout while fasted (far from a scientific study but what the heck).