Should we be doing Gym Workouts fasted?










I am a huge fan of short intense body weight and aerobic work on an empty stomach in the morning prolonging the fast for about an hour after the session is finished. I feel these sessions burn body fat and they are a great start to the day. The sessions I am talking about are either short runs or body weight based met-con circuits like I mentioned in my previous blog post.

As well as this working out first thing in the morning is the best time to get workouts out of the way leaving the day free to live our lives.

What about longer resistance gym based weights sessions?

Maybe I am odd but I have tried to do heavy lifting first thing in the morning fasted on several occasions and have found that I feel very lethargic and weak, my lifts on compounds do not get near to the maximum weight I could lift. As well as this the workouts seem to affect my mood for days to come especially if I push too hard doing a Power Law Based training session.

From reading around I have come to the conclusion most people feel the same and to me it comes down to a few things;

  1. firstly our bodies are in a detox mode in the morning and more geared towards the ridding of toxins and therefore primed for aerobic activity which would include trail running, walking and high rep body weight work.
  2. If you have already fasted from say 6PM the previous evening and had a dinner based on wholefoods (Meat, Vegetables, Good Fat and Fruit) it is likely your muscle glycogen is very low which will stop you performing at your maximum level by the time you get to your workout at 8-9AM.
  3. Resistance work fasted hits your CNS harder potentially effecting your mood for days to come. Especially when done at High Intensity.
Martin Berkhan from has a great insight on workouts when Intermittent Fasting:
Morning workouts and IF      

I’ve been getting a lot of questions on how to structure meals in combination with morning workouts, without deviating from the plan; being that an 8 hour feeding phase is one of the fundamentals of the diet, morning workouts would have one starting the fast quite early, which for most people may feel a bit harder than fasting throughout the morning/lunch hours. Here’s what I’ve responded to a recent post, adressing my opinion on the subject matter:

Anyway, I am interested in your take on working out in the morning and how to fit that in w/ IF. I have been doing IF and feeling great but can only work out in the morning and, so take my post workout meal at that time. Is this ok, or what do you recommend?

“…for morning workouts, I usually recommend compromising a bit. The way I set this up, is to place a certain % of total calorie intake in an 8 hr feeding window pre-and post WO, and then “taper” calories towards the evening (high protein/low carb) in order to make a transition into the fasted phase (as low carb mimicks the effects from fasting to a certain degree). Thus, the feeding phase will be slightly longer than 8 hrs on workout days, but I consider this a good compromise in order to get proper PWO nutrition. Of course, one could go about this by initiating the fast in the afternoon/evening, but many consider this a bit daunting (and anecdtoally, fasting in the morning/lunch hours seems easier).”

What to do if you don’t feel your best working out with weights fasted?
If you must do your primary heavy resistance training first thing in the morning and yu are someone who does not tolerate fasted workouts well I can offer the following tips:
  • Have a piece of fruit before hand like a banana seems to do an amazing job at keeping our bodies in a negative energy balance whilst allowing you to perform well in the morning and burn fat. I have been experimenting with a banana and a shot of expresso pre workout (30 mins before) and it has been great, I suspect my insulin levels are kept low enough to encourage fat burning during the workout.
  • Try and do more light running/pushups/Pullups and squats first thing in the morning and fit in your gym based work in the evenings.
  • Experiment with Branched Chain Amino acids. I am not a huge fan of supplements like these but they will give you energy to get through workouts whilst keeping your body in a fasted state, 5-10 grams will do.
  • Eat dinner later at night. This is a tricky one as we want to go to bed with a somewhat empty stomach as to maximize growth Hormone release so be careful with this one, the main premise is to make the fast before the workout shorter but still be in a fasted state.
  • I will sometimes do fasted resistance work on mornings after cheat meals/dinners as I have normally eaten loads of high carb foods leaving me with plenty of muscle glycogen allowing me to steam roll through workouts, in spite of having fasted for several hours.
The take out point here is that everyone is different I know some people perform fine first thing in the morning whilst others suffer. If you are someone who does not fare well doing heavy resistance work while fasted then I suggest you experiment with some of the tips above and see what works for you or try and schedule your workouts to times you have some fuel in the system.

1 Response to “Should we be doing Gym Workouts fasted?”

  1. 1 wazzup105 December 24, 2008 at 1:51 pm

    I don’t think muscl glycogen will be depleted at all after a night sleep.
    Liver glycogen: yes,
    bloodsugars low: yes,
    but muscle glycogen: NO
    (go read some of Lyle McDonalds articles on depletion, or his UD2.0 book)

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