Intermittent fasting and exercise

[MrsPritchardsPantaloons]

I've been doing roughly 16/8 for about 3 months now (sometimes it's more like 18/6) and getting on well eating between 1 and 8/9ish. I run a few times a week, usually going later in the afternoon. With the days getting shorter, I'd ideally run in the morning. But how does it work if I'm fasting in the morning? Is it possible to run then? Will I just end up exhausted?

Thanks for any tips!

I run 5k in the morning 3 times a week while fasting. I don't feel tired from it. I guess it depends how far you are running.

I work out all the time fasted and it’s fine.

Ah OK ! Maybe I'll try it! I've been doing about 7.5k but perhaps I'll cut it to 5 and see how I get on

When I was really into fitness, I always worked out in the morning and hated eating beforehand as it could lead to nausea or cramp. As I never ate after 7pm anyway and wasn't back and showered and eating breakfast until 11am, that was a natural 16/8 fast, though not an intentional one. I felt absolutely fine.

7.5km will be fine.

I work out fasted and it's not an issue. In some ways I find running easier fasted.

Some people do struggle with it, but many don't. It's an individual thing. Give it a try and see.

Thanks! I tried 5.5k this morning and got on fine. Went about 11, so there was just time to have a shower before I had to get DD down for her nap, then we had lunch after.

I'd ideally like to go a bit earlier, so I'll see how I get on with a longer gap between finishing my run and having lunch

For an alternative perspective you might want to look at Stacey Sims' advice on fasting and exercise - she points out that a lot of the research done into intermittent fasting was done on sedentary men and the results can be negative for women, particularly active women, and particularly women around menopause. It's obviously possible to exercise fasted, but there's a risk that you won't get as good results from doing so (both in training sessions and subsequent muscle development) as you would if you'd eaten first. More research needs to be done but I prefer to err on the side of fuelling. I do try to give myself a 12 hour break when I can but not at the expense of my pre or post workout fuelling.

Good that you were fine with your fasted run, OP.

I work out fasted every morning. I stop eating by 6pm or sometimes a bit earlier, and rarely eat before 12. Always fine, whether I'm doing cardio or weights.

The way I see it is that I have plenty of stored fuel in my body so don't need to take instant energy on board in order to exercise. I quite like the analogy (Jason Fung, I think) about eating before exercise, which is that despite having a well-stocked log store, you're cold so you chop up your sofa to make a fire, which makes no sense.

Everyone's different but it works for me!

@Fallstar interesting analogy! I'm getting back into it after a couple of months break so I'll see how I get on using more of the log store

@UnaOfStormhold Thanks for the alternative perspective! I'm not 40 yet so not quite menopausal so I'll take it a run at a time and see how it goes