Intermittent Fasting Workout Timing

Hi, I’ve got into intermittent fasting a few times when was time to do a bit of cutting and it feels good so I would go back into it. The issue this time is that I always used to fast for the most of the day then have a little meal as a pre-workout and then the rest of my food after the workout. The point this time is that I always train at different times,for expample a might workout tonight and then tomorrow morning,so this gonna mess up the fasting.
How do you guys deal with it? As anybody got any experience on this?

Thank you

interresting about the answer too ! working day and night shift but never know in advance

You can move your fasting window so it always covers your training window or you can just train fasted. The difference in results is probably going to be unnoticeable

Either way is going to suck, I’d go with the one you think is going to suck the least and if you are wrong you can swap for the other. I’d give your body 4-6 weeks to acclimate to the suck before making a call.

All this assumes you are just dropping weight to look a bit better rather than aiming for a bodybuilding comp or some performance goal.

you think that there is no problem if we train fast and then we wait maybe another 6-8 hours before eating after the workout ?

Some people deal with that okay, others have a terrible time with it. It depends. If your goals are performance based, I wouldn’t do this.

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can we still take example my vit D and zinc in the morning, omega and mag at night while fasting or it will interfer ?

I’m in a similar situation.

If I train in the am I don’t intermittent fast. You get most of the benefits by intermittent fasting 2-3 times a week.


so you only fast when you work on the day shift ? do you still use your supplementation while fasting ?

@bigmax: I don’t do day/night shifts. If I train in the morning on lets say on a Monday and Wednesday, then on those days I don’t intermittent fast as I eat breakfast after training, while on the other 5 days I intermittent fast to 1pm as “usual”.

The only preworkout I do is black coffee and a piece of fruit.


It depends on the reason you’re fasting and the length of the fast. For example, one of the greatest benefits of fasting is autophagy (cellular cleansing) but most researchers say that process doesn’t really ramp up until about the 16-20 hour mark. They say that any calories at all, insulin response or not, will officially break a fast in that sense (black coffee and tea are ok).

If you’re fasting in say a 16:8 window (typically skipping breakfast) for fat loss (ketogenic response, lipolysis) then many people say you can have anything that doesn’t produce an insulin response. However the lower the calories from fat the better.

So I fast eating only at night let’s say doing one big meal around 11pm and some more food to put some proteins in after 2-3 hours.
Now it works cause I’m not training because of an injury so I’m fine but if I have to train let’s say today in the morning and having my meals after my workout would mean stop eating around 2 pm,then if the next day I’ll not workout or workout at evening will mean eating at 11pm so between that I’ll have done more that 30 hours fasting at that point which I guess it’s bit too much at that point.

What I’ll do it’s eating normally on training days 4 times at week and fasting on the days off. I think I’ll still get some befenits using this way.

That’s what I do, except I fast on my training days until my evening workout. Then I try to eat in a surplus for the next 24 hours in an attempt to get as much protein synthesis as possible. It seems to be working really good so far, but I’m still in the early stages. I’m gaining some muscle and losing fat but I’m also 42 y/o even though I don’t feel like it. I know my expectations are probably higher than my body will allow.

What I have been doing (mainly for fat loss purposes) is circa 44 hour fasts three times a week, i.e. Mon/Wed/Fri. I will train the remaining 4 days.

Typically, I will ‘break’ the fast late afternoon/early evening using peri-WO shakes and then eat low carb a few hours later (at night).

I have found this style of alternate day fasting pretty easy to maintain. Social/family constraints can be the biggest challenge but I am fortunate here, so it fits my lifestyle.

As has been pointed out by the likes of CT, the downside of such diets is a propensity to overproduce cortisol. This is even more of a factor if you are working out late. Similarly, late eating can mess up your circadian rythmns. So far, it’s working for me but, all going well, I expect diminishing returns over time.

The other angle worth highlighting is the difference between, what I would term a strict, or true, fact and a dirty fast. The former should be water and maybe some electrolytes. The latter includes teas, coffee, maybe some sweetners, flavoured waters, gum, etc. The former is, no doubt, optimum for health and maximum autophagy; while the latter can get you through patches where you’re felling a bit sorry for yourself. While I have done both, I now tend towards the dirty fast.