Exercising on an empty stomach?

I run 6 - 7 miles in the morning on an empty stomach. Did that today in fact. If you ate good the day before then it's not an issue. What your trainer was talking about is the effect of doing cardio with low insulin levels. Insulin is your body's signal to store energy as fat. If it's been 6 - 8 hours since you ate your insulin levels are probably zero.

Your body's opposite signal to insulin is growth hormone (GH). GH signals your body to metabolize fat cells as energy. The theory is that if your body is still producing GH you want to exercise then to take advantage of this state. If you eat food it could change your state to insulin positive and make it harder to lose fat.

Lots of opinions on either side of the aisle as to if this is correct or not. Some people say it doesn't matter. Just record calories burned and calories consumed. It all works out the same in the end. Some will tell you that this is an actual advantage and that if used time after time will eventually add up to a real difference even if the difference is small each day. I'm on the side that believes that this actually is good for you if you can do it. I think it helps.

If you're wanting some fuel before workouts then have something light that's not pure sugar yet can be absorbed and ready to use by your body fairly soon. If you really need the energy then take it because you're not killing all rewards from cardio. It's better to finish than to quit because of low blood sugar. If you can stomach cardio in the morning before eating then do it.

There is no effect on "fat burning". It all depends on what you need to fuel your workouts. Since what you have "on board" can be affected by many factors, there is no way to predict in all situations what you need.

As a general rule, the more intense the workout, esp if you plan on ramping it up pretty quickly, the more important a "pre workout" feeding can be.

I run on an empty stomach because if I eat first I get indigestion really bad.

I run on an empty stomach because if I eat first I get indigestion really bad.

Same here

Meal timing is 100% irrelevant now, you can eat your days worth of calories at midnight and go to bed, it will have 0 impact on body composition. Cardio on an empty stomach is absolute bro science, it's yesterdays way of thinking. That being said, do what you want to do. I generally lift on an empty stomach every morning, i might take a pre workout, but it's all preference.

I do TurboFire and I never eat anything before working out, makes me sick.
Everybody is different: just see what gives you better results ... what feels better ...

I dunno what's wrong with me, but I have tried - I cannot eat anything within 3 hours of working out, or else I will throw up. I do eat 3-4 hours prior, and I do consume protein bars and/or shakes right after and still eat a good dinner after. I think part of it might be that I work out in the middle of the afternoon....

Cardio on an empty stomach is absolute bro science, it's yesterdays way of thinking.

Bro science

Zoladz JA, Konturek SJ, Duda K, Majerczak J, Sliwowski Z, Grandys M, Bielanski W. "Effect of moderate incremental exercise, performed in fed and fasted state on cardio-respiratory variables and leptin and ghrelin concentrations in young healthy men" . J Physiol Pharmacol. 2005 Mar;56(1):63-85.


Like I said you find evidence on both sides. This is not "bro science". We're talking about actual medical trials. The example I linked to showed that your glucose wasn't any lower in a fasted state but your insulin levels are a bit lower.

I usually exercise first thing in the morning or else I might not work out at all. Running with a full belly just doesn't feel good. I don't dare do Crossfit with chow in my belly for fear of throwing it up!

Pretty much all I do unless I'm sick or my schedule doesn't allow me to.