I have been doing 4:30am workouts for about 4 years now. If I don't eat something before, I die during the workout. I eat a banana as soon as I get up, which is about 30 min before the workout begins.
My kids have evening practices and usually eat a mid size meal an hour before-I try to keep the food light,but one is a teenage boy and he puts food away like there is no tomorrow.I always worry that whatever they eat will end up floating in the gutter halfway through practice, but they have never complained of feeling sick or getting stomach cramps.
I on the other hand swim in the AM and in the past had to swim 'empty'-only fluids during swimming and then a decent breakfast.I have finaly conditioned myself to keep down coffee and a banana or half a bagel, but even then I have to wait 1 hour or I feel like stuff is sloshing around my stomach.
My feeling is, regardless of what science recomends here, if you need something(liquid or solid) to help your body work and your mind to focus then do it-but if it makes you feel sick it will reflect in the quality of your workout.
I have been doing 05:00 w/o's for years. I get up at 04:30 and eat nothing. I have had absolutely no energy problems. I do eat a good breakfast after the w/o. Most of us have enough energy reserves to take us through a 60-90 minute session.
Surprisingly, so far I've come up with nothing on this.
I did run across an interesting entry in Richard Nikoley's blog in which he reports no ill effects from heavy workouts while fasting, and notes that this should not be surprising, since it would be odd if mammals evolved in any other way, considering that hunting is usually done when hungry.
Which reminded me of an article I read recently via Science Daily which reports that mammals actually are more energetic when hungry, presumably for exactly this reason.
That logic doesn't work for me personally, but then again I know that my system is all messed up.
But I find the evolutionary logic compelling.
I'll keep scrounging for research.
I am surprised that it's so difficult to find studies on this.
Are you sure about that? Always seemed like an old wives tale to me. If eating immediately before swimming doesn't bother you then I see no reason not to.
If you don't wait 30 minutes after eating, you will sink to the bottom of the pool.
In an exercise phys. class i took recently we were taught that the food you eat the day/night before is what you are using for energy the next day. The food you eat right before a workout will not be used by your body until later on in the day.
If you take a blood sample in a fasted state, drink a high glucose beverage, then take a series of blood samples, what happens to the blood glucose?
I agree that the food you ate several hours ago or more provides the stored energy, but you can dump energy into your blood stream almost instantly via your stomach.
en.wikipedia.org/.../File:Suckale08_fig3_glucose_insulin_day.jpg
Waking up and working out without eating would be impossible for me.
Even doing my swim (or lift) at mid-day, I have to have some oatmeal with walnuts and maple syrup a couple hours before, on top of my breakfast (which I eat as soon as I get up in the morning). Otherwise, I run into serious blood sugar problems.
I'll check our databases when I have a chance and see if I can find any hard research on this.
It doesn't seem to me that a hard workout while fasting is a good idea for anybody, but I may very well be wrong.
I don't know, maybe it's as simple as: if you're hungry eat. I know I wouldn't want to start a workout feeling hungry. And I think there's also a difference between what you'd want to eat before a workout as opposed to (pool) competition where we're talking about events lasting seconds to minutes, not hours.
