On bike nutrition. How much do you put back in?

[flanagaj]

On a recent ride, my Garmin is telling me that I am burning ~ 800 - 900 calories per hour.  Given that your body can hold ~ 2000 calories, you would quickly bonk if you were not refuelling as you ride.

So should I be looking to put back into the system 800 calories per hour whilst I ride so that I do not eat into the glycogen stored in the muscles or do you accept that you are going to eat into your reserves and these will be replenished after your ride?

The only question I have is how you go about putting 800 calories per hour back into the body as that is a lot and given an energy bar is only 250 calories I can see how you would get fed up eating 3 energy bars per hour.

Thanks

[fotooutdoors]

You really can't eat (or at least digest and absorb) that many calories while exercising.  I for one also know that I can't keep up a pace that makes burns 800 calories an hour all day, though I can do it for a couple hours.  When exercising at lower intensity over a long time, your body shifts from using only pre-stored glycogen to burning other stores in addition to glycogen, including any fat on board.  

Various studies have looked at how many calories your body can digest per hour while exercising, and while it varies significantly between individuals (and what you are eating), I have seen the number 300 bandied around before.

In short, eat often, but not too much on the bike, and eat solid meals.  Perhaps especially supper, as you are headed toward a time where you aren't exercising, so your body can do some catch-up before the next day.

If interested, here are a couple studies that looked at this question
http://www.ncbi.nlm.nih.gov/pubmed/15707379?ordinalpos=3&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum
http://www.ncbi.nlm.nih.gov/pubmed/15212750?ordinalpos=4&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum

[Done]

I can't find the source for it right now, but it has become common knowledge that our bodies can absorb about 200-350 calorie per hour. When you're working hard, this can actually be a lot lower.

So, eating 800 calories per hour while riding will not replenish what you burn. The difference comes from stored glycogen, body fat, and even muscle tissue. If you try to eat 800 calories per hour while riding hard, you'll probably end up with gut cramps, nausea, diarrhea, etc.

For all-day efforts, you'll burn a LOT of body fat. That's why most people end up pretty skinny after multi-day efforts. On something like the CTR, I tend to lose about 3/4 of a pound of fat per day. For longer trips, I only lose maybe 1/2 pound per day, because I simply can't maintain a quick enough pace--and thus, I burn fewer calories.

Maintaining blood sugar and replenishing glycogen is important. The former is done by eating 200-350 calories/hour of primarily carbohydrates and maybe little protein. To accomplish the latter, eating a good meal before sleeping helps.

All of that said, I am not an dietitian or athletic trainer. While I've tried to educate myself by reading as many peer-reviewed studies a possible, the world of sports nutrition is infamously rife with all sorts of conflicting information. The supplement companies are notorious for exaggerating the benefits of certain approaches--or even sometimes making stuff up. It never hurts to try a few different nutritional approaches, and then see what actually works for you.

[flanagaj]

That makes very interesting reading and thanks for taking the time to reply.  This has raised questions and I think that could be the reason why a 4 hour ride at around my lactate threshold of 157 really does take it out of me and makes me feel pretty lousy for the rest of the day and the day after.

What I am trying to work out is how I go about conditioning my body to work more efficiently at lower heart rate zones so I can sustain prolonged effort for 8-10 hrs per day for many days.  Do I do more steady mileage at a much lower heart rate, or do I do really hard shorts sessions to get the AT up from 157?

[Done]

This has raised questions and I think that could be the reason why a 4 hour ride at around my lactate threshold of 157 really does take it out of me and makes me feel pretty lousy for the rest of the day and the day after.

Yeah, riding that hard for that many hours will leave most mortals pretty whupped!

Eating the right stuff before and during the ride is crucial. I try to eat a few hundred calories before starting, and then 200-300 during the ride. If I'm pushing hard, I drink my calories in the form of energy drinks. If I'm taking it more casually, I'll eat anything from sandwiches to fig newtons to Powerbars. Drinking properly is also important, and electrolytes can sometimes help--especially if you sweat a lot.

I try to eat a bunch of carbohydrates and protein immediately when I finish. A turkey sandwich is good. Or quart of orange juice, a pack of jerky, a couple of apples, and some yummy chocolate. If I ride for more than a couple of hours, I find that I need to keep drinking until bedtime.

As far as training for longer efforts, there are lots of different approaches out there. I've always found that the more time I spend in the saddle, the faster and longer I can ride. Not very scientific, but it works. I don't have a methodical training schedule. Instead, I ride hard when it feels good, and I kick back when I'm tired. Sometimes I ride hill intervals until I'm ready to barf, and sometimes I spin along on the flats admiring the view. I have no doubt that structured training has some great benefits that I'm missing--but I find that I'm happiest overall when I'm doing what feels good. It's pretty easy to burn out on fad diets, strict training regiments, etc.--so find what works for you and make sure that it's sustainable.

[Area54]

During training, get your body used to running all sorts of fuels too - might have to run on some greasy fry-up from a burger joint, or purely on lollies from that service station at 1am. Don't wash your hands during training either - try to expose yourself to as much diverse bacterial flora as possible to harden that tummy up - cement is not enough...

[Done]

Don't wash your hands during training either - try to expose yourself to as much diverse bacterial flora as possible to harden that tummy up

No offense, but that may be the wackiest bit of "nutritional" advice that I've ever read.

I don't think that you'll find much scientific support for idea that exposure to most infectious bugs, including common food-borne ones like E. coli, Listeria, Salmonella, Campylobacter, Hepatitis-A, and Norovirus, will "harden" your gut. Further, washing somewhat regularly has also has been shown to reduce occurrences of non-food-borne pathogens, such as influenza and the common cold. Seems to me that intentionally not washing will just result in getting sick more often--which means fewer training days.

[Mark_BC]

I also believe that when you are under high exertion stress your immune system doesn't work as well so you would be more prone to getting sick if you do come in contact with the pathogens.

[Area54]

Use common sense with it. Obviously don't expose yourself to unnecessary risk, just raise your tolerance to imperfect conditions.

[Done]

Use common sense with it. Obviously don't expose yourself to unnecessary risk, just raise your tolerance to imperfect conditions.

Sorry, but there's no scientific sense--much less common sense--about what you've proposed. Recommending that someone stop washing their hands "to harden that tummy up" is ridiculous. Regardless how it's framed, it's the epitome of an "unnecessary risk."

The best things that someone can do to prepare their immune system for a big event is:
1. Eat lots of healthy unprocessed foods, including fruits and veggies.
2. Get lots of sleep.
3. Be careful not to over-train.
4. Stay hydrated.
5. Stay clean, and avoid contact with sick people and environmental pathogens (ie, wash your hands).
6. Maybe take extra vitamins, depending on diet.

Depending on where you're going, vaccinations are a good idea. Typhoid, Hep-A, etc. are surprisingly common in some parts of the world.

During a big event, your immune system will probably weaken. Lack of sleep, low-grade food, physical & mental stress, etc. are all known to suppress immune-system response. On top of that, it's hard to stay clean after bathroom breaks--especially in public areas without running water. Carry baby wipes for your butt, and maybe a small bottle of alcohol (Purell) for your hands to clean up before eating.

[Mark_BC]

I think it's true that if you want to get used to local bugs you need to introduce yourself to them in a controlled way -- that's why locals don't get sick from drinking the local water whereas visitors do (even here in Vancouver I heard that Europeans can get sick when they come over because it's a new set of bugs to deal with). This isn't for viruses and other nasty pathogens and such, just for tummy bugs. Of course you want to do that BEFORE you require a lot of performance out of your body, not during.

[windowace]

Hmm..I bet there is some scientific proof, although I can't reference it.  The reality is, most of the 'bugs' were talking about are in and around us all the time.  The reason we don' get sick is because our immune system can control their populations or the quantity of the pathogen is low.  It is when the exposure population is too large, or our immune system is compromised, or a combination, and our system is overwhelmed.   That being said, we probably have enough exposure to the likely suspects that we don't need to go out of our way to expose ourselves to them.  Regarding on the bike nutrition I think what has been said is pretty good advice.  Our digestive system can process 200-350 cal/hr if not under extreme stress (anaerobic or near).  You can not replace calories at the same rate you burn them while exerting yourself at the levels we are talking about. About the best you can hope for is the 200-300/hr.  If you take in more than that it will just sit in your stomach, sloshing around, waiting to be processed.  That usually is not a good thing. The difference in what you take in and what you are processing is mostly compensated for with fat. As long as oxygen is available and some other chemical components, our bodies will primarily convert fat to sugar as fuel for sustained effort. Our bodies prefer simple carbohydrates (sugars), it is easier and faster to convert to a sugar that is 'burnable".  But after available carbs have been used (our liver stores about 2000 cal worth) our body goes to fat stores for energy.  A pound of fat on your body contains about 3600 calories.  You body can convert that to energy.  Even a  lean individual (10% body fat on a 150lb person = 15lb fat) has days if not weeks worth of energy stored on their bodies.  So you replace what you can while you are moving 250ish calories, you take in the same amount before you sleep - 6 hrs sleeping = 1800 cals - and then exert yourself at a level that allows your body to convert fat to sugar and you can move for a long time.  If you exert yourself at too high of a level and you have already used up your easy energy (glucose in your liver and already processed carbs) you bonk because you body now needs time to convert fat to sugar.  So, in my opinion for ultra distance racing/riding you really shouldn't carry more than 250-300 cal for each hour you will be out, assuming you can refuel at will.  Any more than that is extra weight.  Additionally, you really shouldn't need anything for about two hours (2000 calories in a well stocked liver). If you are out for more than two hours then you go to the 250ish cals per hour starting almost immediately.

[windowace]

I guess I will add that you don't need/have to replace those calories while you are moving.  You can keep going without doing so, but probably not at an intensity that will 'tax' your cardiovascular or muscular system in such a way as to trigger an adaptation response.  Which means you are out there spending time and not getting the return on your investment that you could if you were optimally fueled. Plus you may feel crappy at the same time.  For most physical training, we need to push our bodies to, or past, the edge for it to "think" it needs to adapt. On the other hand, your body may get better at working in those conditions so there still may be a training benefit.

[Mark_BC]

I just got back from an awesome snow biking / packrafting long weekend. So amazing! And I drank nothing but pure creek water, no filtering. I only take from road cut banks where the groundwater drips down the moss. No surface water, no problems. Also melted some snow too but that didn't taste as good from the dinner residues in my pot.

I started out at the snow line at 500 m, then rode 8 km up the plowed road to the Callaghan Valley near Whistler, at 800 m where the snow trails began. Then another 12 km up to 1300 m over the snow. I didn't bonk, but ate a few power bars on the way up. Had a good warm pasta dinner. That night it got cold, probably -15 C. Burned lots of energy to stay warm. Tried summitting the pass over to Squamish with snowshoes but too hard pulling the packraft / bike on the snow. So came back down the next day and today I went for a little 10 km ride up, 10 km packraft back down the Squamish River.

My body seemed to handle the demands OK, even after hours of exertion. At the end of the first day I was pretty tired, part of that was the altitude too.

Can't wait to see how the Gopro footage turned out, I'll post a trip report but it might be a few weeks before I get it sorted out.