[beachgal]

I apologize if this topic has already been addressed--the search function isn't working properly right now and so I don't know if I can trust the results I got when I tried to find other posts about this topic.

I recently read an article that confused me deeply about glycogen, eating, and exercise. Here's a link to the entire thing. The part that confused me is quoted below:

Lets start with some physiology that will help make sense of my time recommendations. The body stores food as glycogen in the liver. The liver is about a 3 pound organ that is capable of holding 300 calories of digested food. During typical daily activity the average human burns 100 calories per hour. So, in 3 hours our body will have burned off the glycogen stores in our liver. At this point our body begins to switch from utilizing glycogen to utilizing stored body fat. This is the point at which we want to turn up the energy output (via exercise) to maximize fat loss.

So, ...you would want to wait three hours after eating before exercising. If you eat and then immediately exercise your body will be utilizing the food you just ate for energy and thus will not be tapping into your stored body fat. This is why I can go to the gym and make significant changes in my body while others look the same month after month. They are only burning the food they ate and never getting into their body fat.
...
Now, lets say that you waited 3 hours after eating to workout. Your entire workout you were utilizing stored body fat for energy. If you were to wait an additional 30 minutes after your workout before eating, what would your body be using for energy during that time? Stored body fat! And it is using it at a high level because your metabolism is still quite high from the workout. If you wait 60 minutes after your workout to eat then your body will be using stored body fat that entire time.

My nutritionist told me about glycogen. What he said differs quite a lot from this--basically that I should eat within 30 mins after exercise to replace my glycogen stores. If I don't, my glycogen will be at a lower level when I do my next workout.

My gym recently installed a smoothie bar, so they've been posting information about nutrition and fitness. One of their posters noted that if you don't replace the glycogen stores, it will go after protein in other areas, such as your muscles (which I certainly don't want to lose...).

I'm having a really hard time finding the truth here. But I've never heard any of the really smart exercisers I know talk about waiting more than 3 hours after eating in order to work out. The bad spelling and punctuation in the article makes me pause, but what the person writing (who is puportedly a "doctor") says makes enough sense for me to wonder.

I'd love help navigating through this confusion. Here are my major questions:

1. Should I be waiting 3 hours after eating before starting a cardio workout if my goal is to burn fat?
2. Should I worry about eating something within 30 mins. after working out or does that have no impact on my glycogen levels?
3. What do I need to know about glycogen in order to maximize the effects of my workouts?

[Tarisaande]

Well, just for starters, looking at your ticker you have lost about a zillion pounds already presumably not waiting 3 hours after eating to exercise every time, and I suspect a large percentage of that was fat. I never followed any such rule, often exercising after dinner, and eating a snack (fruit, a fiber one bar, something) after work on the way to the gym, and it certainly hasn't hindered my own efforts.

Glycogen is like, a temporary energy store for your muscles. It is easy to access and use during exertion, and personally I think it is probably good to eat something (ie a snack, not a humongous meal which can make you tired) shortly before a workout to assure you have some quick energy. If you have not eaten for a long time before a workout you may get tired faster or feel more drained had you not eaten before. This is definitely the case for me.

As for waiting 3 hrs because all your glycogen is used up, I can't give you scientific details, but that is not the only energy your body taps into during the day. Using the simplistic logic of the article, you can just switch it around, eat a snack, work out, use up the "new" energy AND your glycogen, and then wait 3 hours before you next meal during which the body has to "burn the stored fat" right?

It's really a personal preference for you. If you feel better exercising after a longer fast period, that's the right way FOR YOU and will give you the best results in the long run.

[ennay]

yadda yadda yadda.

Eating within 30 minutes after has repeated testing that shows improved recovery. This is important so that you can kick butt on your next workout. Caveat...most of the testing has been done by companies like gatorade, but some independant studies have shown the same.

The rest is jibber jabber that has not been scientifically proven. Eat when it works for you. I dont eat before working out in the morning cause good god I cant possibly get up any earlier. I do eat if I am running later. Or if I am planning a hard workout. Or if I wake up ravenous.

[beachgal]

ennay, you're funny! Thanks to you both for the thoughtful replies.

I picked up the flyer from my gym and here's what it says:

Since the human body can only store between 200 to 500 grams of glycogen, it is entirely possible to burn all of those calories in a 60-90 minute session of intense exercise. Glycogen must be present to burn fat; if not available, your body converts protein into glycogen...

If you don't replace the glycogen (stored sugars) that you burned during your workout within 30-45 minutes of your last rep, your body's metabolism begins to quickly slow down cannibalizing its own muscle tissue for energy...BAD.

Of course, they are trying to sell their recovery shakes, so I realize that this information is probably leaning towards what they want me to believe. Nonetheless, it seems to totally contradict what the earlier article said (in that it implies that fat burning is impossible without glycogen...and the article said you need to get rid of the glycogen before you can start burning fat). Anyone know the answer to this?

Okay, so the bottom line I'm hearing from those who posted in reply so far is:

1. eat within 30 minutes of working out (not something big, just a snack)
2. don't worry about whether it's been a certain amount of time since you ate (usually it's been about 2 hours since I ended my meal when I go to the gym) before you workout unless you find it makes a difference in how you feel

Is that it?

[peccavi]

Sounds about right. I've heard way more info that sounds more like the flyer from your gym than from your other article. I'm almost positive that if your body is needing quick energy during a cardio workout and it runs out of glycerin, it doesn't just switch to suddenly burning only fat, because burning fat doesn't really do as much for our bodies.

This kind of reminds me of the "fat burning zone" myth. Sure, if your heart rate is under a certain number, the PERCENTAGE of calories you burn from fat may be higher. But that's it. The total amount of "fat" you burn per minute is still going to increase the harder you are working.

Exercise myths bother me even more than nutrition myths for some reason. I think everybody should just GET MOVING and stop trying to convince people that exercising in a very specific way will give them miraculous results. So just do what feels right.

[ennay]

200-500g of glycogen is 800-2000 calories. Unless you are way underfueled (i.e. a very low calorie diet) MOST people fall in the middle of that range.

Yes you can cannibalize muscle, it is possible. The 30 minute window is when the body preferentially stores glycogen so that tomorrow you will be on the high end of that range rather than the low. And trust me, if you run OUT of glycogen you will know it. There will be no question in your mind if you get there. It is called "the wall" and it isnt just getting really tired. It is getting a cement load dropped on your body.

But here's the thing. You can replenish with a "recovery shake" filled with god knows what kind of chemicals and a bunch of mumbo jumbo "supplements" or you can replenish with a turkey sandwich or a yogurt or etc. etc.

Some carbs, some protein...oh wait...like REAL FOOD.

[MariaMaria]

You can replenish with a "recovery shake" filled with god knows what kind of chemicals and a bunch of mumbo jumbo "supplements" or you can replenish with a turkey sandwich or a yogurt or etc. etc.

But... but... it's not magic! The turkey doesn't come with weird pseudoscientific stuff tattooed on its butt! Real food can't be as good as what we buy in plastic! It's all got to be far more complicated than "eat well, work out, stop mindf*ing something that's not all that complicated."

[beachgal]

You two are hilarious! I've never tried the shakes--I'd rather stick to real food or shakes I make at home. But I was interested in the information because it jived with what my nutritionist told me. Usually I work out after eating a meal and before my snack, but this summer, I've been working out after my snack, but still have to make dinner before I can eat after. So I've been trying to figure out if I should have something small within 30 mins. after workout out--like a small piece of fruit or a couple of almonds--or not.

Thanks for the great advice!