Fasting and Exercise

LtHammerhead

Looking for bit of advice. I’ve started doing a 16/8 fasting regime. Most of the time it’s a non-issue as I generally get in my fitness in the afternoon, in the middle of my eating window.

On Saturday mornings though, I typically go for a big bike ride, minimum 2 hours and this is before my eating time. Should I just not fast Saturday mornings, change my window..what do others do?

Today I didn’t eat until after the ride and was overall fine. Is that the best, just go by how I feel? I carry snacks for “just in case” and drink plenty of water.

L1zardQueen

I would go by how you feel. Make sure, however, you are eating the appropriate amounts of calories for your goal.

KarenSmith2018

If you want to do 16/8 everyday just make sure your bike ride is low intensity and the fuel from the previous day should see you through. Personally I just fasted a couple of days a week on my rest days which were lower calorie days to help with calorie adherence

MarttaHP

I eat within a 2-3-hour window in the evening. I exercise in the middle of the day, so always fasted. I only ever eat before some of my long runs (2+ hours) I've been doing during marathon training, because I wanted to see how my body would react to a breakfast, since I didn't dare to try to run a full marathon without eating anything first.

For me, it doesn't seem to make a difference. Sometimes my long runs are fine when I haven't eaten, sometimes they're exhausting. Sometimes they're fine when I have eaten, sometimes they're exhausting. I guess it comes down to how I manage to eat in general, whether I'm fueling enough the rest of the time.

So yeah, I'd say go by how you feel.

sweetdaisy13

I follow 16:8 and have a small lunch at 1pm, followed by my main meal around 8pm.

When I run during the week, it's in the evening after work and my lunch would have been something small like an apple, Yogurt and a few olives. But during the weekend, my longer runs are almost always run in a fasted state. I will only tend to eat something small before a run i.e bowl of porridge or banana if my runs are going to be 2 hours plus (trail/mountain marathon training).

I've been fasting for a couple of years and I'm used to running in a fasted state. Sometimes I feel lethargic towards the end of a run, other times I don't, but I can't say that that is solely down to running in a fasted state. It depends on how busy my week is.

I always carry squash/cordial to drink on runs which are 12+ miles and for longer runs I carry a small "emergency" chocolate biscuit/bar but have never needed it. It's only there if I'm in the middle of the mountain and I feel unwell or faint and need some sugar.

SuzanneC1l9zz

I've been working out fasted for a couple of years now. I don't do IF, it just works better for my schedule. I get up, have a cup of coffee, and work out. I'm getting dressed within half an hour of my alarm going off. I have a small home gym so there isn't even travel time. I adjust my intensity based on how I feel, but it's rare not to feel completely normal and strong. Immediately after my shower I have breakfast, and then on with my day.

ninerbuff

I train every morning fasted. The night before, I'm carbed up at 10:30pm. Not an issue.

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SnifterPug

Go by how you feel. I train fasted every day.

AnnPT77

Try it, see how it goes. Put a snack in your pocket or bike bag (fast carbs, probably best), just in case it doesn't go well. Maybe start with a shorter ride, or a trial course where you can loop back to start via a short route, just in case.

Lots of people do great working out fasted. I don't handle it well, personally (feel miserable, hit a wall early if there's any intensity). Not everyone follows the same pattern. Think about how to do an experiment or two, with some insurance built in.

sijomial

Really depends on how intense your two hour ride is and how you personally react to fasted exercise and what your overall diet is like. You haven't said if you are in a deficit, maintaining or trying to gain weight - that will have a bearing on your fasted exercise capability as will how long you have been exercising fasted (you do adjust over time). You haven't said if this is an easy pace ride or pushing hard to set PBs or fast times.

Gentle two hour ride for someone who isn't in an aggressive calorie deficit probably isn't an issue.

Two hours pushing hard and in a big deficit I'd guess almost certainly you will hit problems.

Personally a two hour moderate intensity ride (about 16mph average, not too much climbing) I wouldn't find any issue at all with no breakfast and just drinking water. Zero performance impact.
Longer duration or higher intensity (lots of climbing or higher speed) and I'll be eating a carby breakfast. Very high intensity or three hours and up I'm eating before and also fuelling as I go.

Experimentation required and yes carrying some "emergency carbs" a very good idea, if you start to feel like your performance is suddenly dropping carb up quickly as you don't get much warning when you "bonk" (or hit the wall as runners call it). It's not just hugely unpleasant, it's actually dangerous (mental confusion, loss of motor control).

callsitlikeiseeit

I dont eat breakfast, or at least rarely do. Not because of any IF program (all that is is a way to reduce calories) but because if i eat breakfast... I'm going to be starving all day and over eat. and ... i just dont want food first thing in the morning. I go to the gym in the morning, then run any errands i have to do, then go home and eat lunch (usually an early lunch but I'm up at 4 am)

As long as your energy levels are fine for your workout, there's no need to change your eating schedule. If you do not have energy for your workout, then reconsider your meal timing.

FitAgainBy55

callsitlikeiseeit wrote: »

I dont eat breakfast, or at least rarely do. Not because of any IF program ...

Isn't it funny that there is an entire program built on something people have been doing for years and years -- skipping breakfast

When I used to race and train I ran all my runs in a fasted state except for my long runs over 1.5 hours. You can train your body to adapt to any type of feeding schedule. It sounds like you are prepared with your emergency carbs if needed, so experiment and adjust as needed.

LtHammerhead

Thanks for the thoughts all. I always carry water and snacks just in case.

In general I felt fine and didn’t experience any performance issues, just was wondering how others handled it.

riffraff2112

Super intense cardio fasted can sometimes make me dizzy. Steady state stuff causes no issues. I bring a power bar and some decent electrolyte drink if I am not certain how hard I am going to push myself.

MikePfirrman

riffraff2112 wrote: »

Super intense cardio fasted can sometimes make me dizzy. Steady state stuff causes no issues. I bring a power bar and some decent electrolyte drink if I am not certain how hard I am going to push myself.

This is kind of where I am with it. I do really intense HIIT stuff two days a week. I fast pretty much everyday, just longer on my other five days (four of which are easier Steady State stuff).

On the HIIT days, I also do lighter lifting. So I might have a small snack at around 10:30 or so (16 hour fast). On the other days, I'll regularly go 18 or so without issues.

westrich20940

I think it depends on how you feel -- I run fasted for example....you just have to make sure that overall - you're getting enough nutrition/calories to support your workouts.

cwolfman13

What kind of a ride...a 2 hour cruise is a lot different than 2 hours at tempo and maintaining wattage. I haven't done any kind of "IF" since last summer, but I've done "IF" periodically at times for years for various reasons. I have no issue skipping my breakfast and doing a lifting session early on Saturday mornings fasted...in that I just get up around 6 and get to the gym by 7...or other similar types of workouts, but these are typically 40-45 minutes to 60 minutes max.

I do have issues on my bike going for that long fasted. A 2 hour ride is usually going to put me somewhere between 30 and 40 miles depending on my route and terrain, and fasted, I am ultimately unable to maintain my wattage for the duration so it does impact my performance...even fueled, I'm usually mentally reaching to maintain my power at the end anyway. I also don't necessarily feel bad during the ride, but I am far more lethargic and fatigued for the rest of the day which I hate because if I do a ride like that it's early on a weekend, and I have a lot of other stuff to do the rest of the day.

Personally, it's not my bag...there's nothing magical about skipping meals other than calorie control so it's pretty much a non starter for me in regards to long duration cardio.

sijomial

LtHammerhead wrote: »

Thanks for the thoughts all. I always carry water and snacks just in case.

In general I felt fine and didn’t experience any performance issues, just was wondering how others handled it.

Five rides so far this week:
For a 64 mile ride I had a milkshake with a scoop of whey protein and granola before I started, sports drink mix in my bottles and a couple of malt loaf bars to snack on while riding.
The other 15, 36, 30, and 24 mile rides just fitted in those day's eating schedules and I only drank water.

Maybe I'm an intermittent, intermittent faster?

ninerbuff

I run intervals 3 days a week. And then lift right after. So the night before I carb up. I don't eat again till after 12pm

A.C.E. Certified Personal and Group Fitness Trainer
IDEA Fitness member
Kickboxing Certified Instructor
Been in fitness for 30 years and have studied kinesiology and nutrition