Training & Nutrition - How long does it take for food to kick in?

How soon does a banana, energy bar, etc take to kick in after eating? What about energy drinks like Red Bull it seems to kick in pretty fast.

Depends on the food as well as your metabolism but generally simple carbs(particularly refined) digest very quickly while a heavy meal with more complex carbs and fats can take several hours to fully digest if your metabolism is slow.

Minutes. Simple carbs can have an effect on blood sugar in minutes.

It doesn't take long. Generally, if I stop and eat, by the time I am back on the road, I feel this difference. I have noticed that sugary foods tend to kick in faster than non sugary foods. I think that fatty foods or proteins would take quite some time to kick in so avoid chugging olive oil or eating beef jerky, but I don't think any cyclist does either of those.

I recall a friend of mine and I were feeling a bit pretty hungry on a ride and we had been going for about 2 hours on a cool morning with light rain. We became hungry but it was a Sunday morning and nothing was open. We found a little restraurant that had a bunch of trucks pulled up in front. We went in and the truck drivers thought it was hilarious that we had gnats all over our faces (we were constantly wet from the weather and we had been riding through the odd swarm of gnats). So we washed those off and sat at the counter. We each ordered one pecan pancake. The pancake was pretty large and was gone in nothing flat. When we hit the road, we both felt a whole bunch stronger. It felt as if we had directly injected the pancakes into our blood streams.

well it depends on the food... something like a ham sandwich or pasta can take quite a while, but something sugary like a coke or an energy bar works pretty fast.

my rule for racing: don't bother eating anything the last 15 minutes of the race b/c you'll use energy digesting it but won't gain any benefits until after the race.

i'm not sure if it's right, but my rule of thumb for solid foods like energy bars and bananas is 15 minutes. energy drinks should be even faster on the order of 3-5 minutes?

As others suggested it depends on your body and what you ate.

I was always told that in order to get the full benefit of exercise after eating to wait about 45 min. to an hour after you eat to exercise.

Now thats not to say that you can not exercise after you eat. You can as long as it does not make you sick to your stomach. But you may not get the full benefit of the exercise because your body is also busy digesting food.

It depends.

Something with simple sugars that is digested (ie- a snickers bar) is more easily digested because simple sugars are already in it's most basic form. Therefore, it takes less time for it to hit your bloodstream.

Something with more complex sugars (complex carbs), like an energy bar takes a little longer for the body to digest, simply because longer branches of sugar are present in the foodstuff. The body needs to break the more complex carbs down to the simple sugars first, then it can use the sugar for energy. The good news about using complex carbs, or rather, those energy bars, is that since the energy bars are broken down more slowly, the body can use the glucose obtained from the breakdown over more time. So it's better for you to use the energy bar than the snickers. The snickers will give you the quick energy, but it will be easily digested and used up quickly as an energy source. As a result, you'll start feeling hungry again within another hour or so, depending on how strenuous your exercise is. The energy bar will be metabolized more slowly, so the body will be able to use the glucose produced from the energy bar over a longer period of time- so you'll last longer.

We all know that in order for ATP to be produced by the body to provide energy to the muscles, oxygen needs to be present to break down that sugar (glucose) molecule in the Krebs Cycle (see http://www.bikeforums.net/showthread.php?s=&threadid=25789 for a detailed explanation of the Krebs Cycle and how glucose is used for energy in the aerobic and anaerobic systems). So if you're bonking, it's the lack of glucose in the body, which means less ATP produced, which means you gotta stop and get some more energy. If you want to maximize your energy output for a longer ride, go for the complex carbs. If you're in a severe bonk and you need the quick energy, take the snickers or the pancakes.

If you're properly eating before your long ride, go with the energy bar, or a food with a longer sugar chain (like a banana) over a pancake or a snickers. Then during your ride, you'll want to take that energy bar or banana before you lose the energy of the pre-ride meal so that you'll always have a continuous source of energy.

That's the short version... I gotta get ready for work! I'll do the long version tonight if people are still interested OR if someone else hasn't already done it.

Koffee

Koffee your right, kinda. A snickers bar is a bad example, becuase it contains quite a bit of fat and protien its not all simple, non complex carbs. The fat and protien affects the glycemic index quite a bit wich affects how quikly the carbs enter the bloodstream as glucose to then enter muscles and go into the krebs cycle.

A better example of simple carbs would be energy gels, sports drinks, a banana, ie foods that are pretty much only carb and have high GI's. Glycemic index is a measure of how quickly food hits the bloodstream. These types of food are best eaten during very high intensity rides, things like races or a hardcore climbing or interval session.

I need to go now but there is lots more to say about this, I could probably right a book on this.

As far as the examples I provided, I was talking in pure terms of complex verses simple carbohydrates. Anything that is a simple sugar (C6H12O6)- single branch is a simple sugar. If you look at the snickers bar, it has A LOT of pure sugar (c6H12O6)- it's the quick energy that I was referring to vs. the complex carbs of an energy bar, which has maltodextrin, which is a complex carbohydrate that must be broken down to glucose (C6H12O6) before the body can use it for energy to drive the anaerobic and aerobic systems.

I don't totally take in all the hype of the high vs. low glycemic foods. From all the conventions I've been to, there still is controversy as to how the glycemic food index affects performance. It is not emphasized as much as the importance of complex vs. simple carbohydrates, which are clearly used by the body differently, depending on how long the carbohydrate chains are that need to be broken before used by the body. There are just simply not enough studies out there involving athletic performance and glycemic foods, although there are studies done for diabetics (where the term "glycemic index" came from). I hesitate to tell someone to eat foods based on a scale that needs a bit more study applied to athletics, especially when they are training for important events. I'd rather stick with the tried and true until something more substantial is released from the research professionals.

Keep in mind, bananas are complex carbohydrates, not simple carbohydrates. They are long chains of disaccharides that need to be converted to monosaccharides before the body can use them to produce energy.

Also, you've kind of mixed up the glycemic info- it's low glycemic foods that are promoted to be eaten before exercise, and high glycemic foods that are promoted to be eaten after exercise (according to my latest nutrition lecture I attended two weeks ago at my convention). Examples of high glycemic foods (glycemic levels in parenthesis) are: watermelon (72), waffles (76), jelly beans (80), honey (73), donut (76), gatorade (111), and Cheerios (74). Examples of low glycemic foods are: skim milk (32), peanuts (14), apple (36), cherries (31), plain yogurt (20), boiled soy beans (21), and boiled barley (36).

Bananas had a glycemic index of 79, whereas snickers had a glycemic index of 59. And that power bar? It had a glycemic index of 83.

I think the glycemic index has merit- it just needs to be studied more and applied to the fitness setting before people can start making claims. It works more for the diabetic, but as we all know, it's common for something that's used by one population to be taken and modified by the fitness world as the newest hype on how to work out. :(

Koffee

As a P.S., our lecturer compared the glycemic index for table surgar and a baked potato- both had a glycemic index of 142, but at the same time, eating both would serve for different interests! It was just one of the problems of the glycemic index.


Koffee

Originally posted by johndoug
How soon does a banana, energy bar, etc take to kick in after eating?

It depends on what I eat. Microwave burritos take about 8 hours to percolate in my system before I start gassing the room. But bananas are quicker (about 5 hours) and also the most powerful - I can actually make people leave the room crying :0)