Carbonfiberboy 

Calories per hour is going to depend on where your effort is on the graph you referred to. The longer the ride, the lower the power and thus the more fat one burns as a percentage. I think that's the explanation. That said, experiment and see what happens. The tell is that your HR drops for the effort if you're underfed. It's a good early warning.

About the eating early, I use a 2 hour fasting window, seems fine, and the idea is to stabilize your blood sugar, same idea as eating small amounts frequently. Probably depends on what you eat. Before a serious ride, I "eat" the same malto stuff I'll use on the ride, so it's really quick.

PeteHski

On low intensity training rides up to 3 hours I eat very little (or not at all) and often just drink water. On higher intensity rides up to 3 hours I fuel with liquid carbs, gels and bars. But not many. Maybe a couple of bars, a bottle of carb mix and the odd gel.

On competitive events much longer than 3 hours I consume as many carbs as I can comfortably tolerate throughout the event, which is about 1 bar + 2 gels + 0.5L of carb mix per hour. As the hours tick by, I find it harder and harder to take in solid food and resort more to carbs in liquid or gel form. The longest events I do like this are under 10 hours and I don't ride anything longer. I can take in approx 80g of carbs per hour in this mode. I know pros can and do tolerate a lot more. I also know it takes training to increase your tolerance to carb intake on the go, but I don't push that too far as I doubt it's particularly healthy.

If I'm racing flat out on Zwift for an hour or two I will also fire down a couple of gels and a bottle of energy mix. I find it just makes it easier to keep putting out the repeated efforts required without fading badly at the end.

ZHVelo

I do. I go threshold if there is just one climb, and SS when there are multiple. I guarantee you for rides 3+ hours long you will feel a difference at the end depending on how much you fuelled throughout.

Hermes

Word. For me, nutrition on the bike is about the right consistency and content of nutrition so that my stomach can manage it.

terrymorse 

Indeed. Consuming things my stomach can handle is very important.

I used to ride with the local club over the mountains to to coast, where they would have a lunch break. If I ate any "real" food, the ride back over the mountains would be unpleasant. It felt like I had swallowed a basketball.

Carbonfiberboy 

A pastry with coffee or maybe a Hostess Fruit Pie. That's all I can tolerate and still climb. Drinking plenty of plain water with an Endurolyte can help that basketball feeling. One has to dilute it down to get to the osmolality that'll go across the stomach wall.

MoAlpha

That's not the food, it's the sympathetic nervous system diverting blood flow to the muscles and away from the gut and decreasing gut motility. It gets much worse in the heat.

MoAlpha

That's not the food, it's the sympathetic nervous system diverting blood flow to the muscles and away from the gut and decreasing gut motility, resulting in a shutdown of digestion. It gets much worse in the heat.

terrymorse 

Thanks for the clarification. Whatever it's called, it is quite unpleasant. Only a candy bar or cookie for me. Maybe a brownie, but that's all. The "real" food can wait until the end of the ride.

I often see others gorging in the middle of a ride with sandwiches or burritos. I don't know how they manage.

downtube42

I find the deeper I get into a long brevet, the less happy I am with carbs, and the more I crave and tolerate fat & protein. 100+ miles in, I feel like I can eat anything. Burritos, pizza, cheeseburgers, anything is fair game. Some of my fellow randos cannot tolerate such food. Maybe further study would turn up why, but that's my observation.

My feeling is my stomach is tired of carbs and wants something else.

GhostRider62

Me too.

After 3-5 days, the stomach is like a blast furnace. Something changes. Whatever I throw in, it goes poof. It demands something along the lines of 4 Egg Mcmuffins for breakfast and 2 Quarter Pounders with cheese, two apple pies, and a large shake for dinner. I can drink various carb solutions but that isn't practical on a long ride. 400 kcals/hr is 100 grams and let's say it is a 24 hour 400k. That would be over 5 pounds of sugars to carry. There are very good reasons we crave fats and proteins.

MoAlpha

I can get the same thing for hours after a long, hard ride, especially in the heat. In my case, I attribute it to old age, bad genes, and unfitness.

Elite athletes actually show evidence of impaired gut wall integrity, bacterial invasion, etc after hard events and the extreme case is exertional heat stroke, where people can infarct bowel or die from the cytokine storm brought about by immune response to bacterial antigens leaking in from the gut.

Carbonfiberboy 

That's all due to the fact that you're riding at a relatively low intensity to do that sort of thing. I've seen riders with the worst digestive problems on the the first major climb of the day when they are still relatively fresh and going hard. Low blood flow in the intestinal wall is what I'd guess.

It's not going to take you 24 hours to ride a 400k at that level of burn, 800kJ/hour. It only took me 15 hours saddle time to ride a mountain 400 at 250 kcal/hour. I did it on probably 80+% carbs, still riding well at the end, no problems. I can't burn much fat in Z3. Now on a multi-day brevet, that's another story. Not much Z3, nope. No way could I have ridden another 400 the next day. I was toast. Fueling choices depend on what you're doing, which dictates pace which dictates optimal fueling.

Jughed

Since I'm on a very restrictive diet for day to day life, a century ride with food stops = game on at the feed station. Lunch on our MS150 ride is full on Hoagies (sub sandwiches) and sometimes pizza.

I chow down and eat some forbidden foods. I feel fine during the ride, it's afterwards that I pay the price.

GhostRider62

I've never taken 24 hours to do a 400k, that was just to make the numbers round.

My main point was after several days, my body will crave and will demand proteins and fat.

Yes, I will not eat immediately before a threshold climb. This is so basic as to be obvious.

On something like a hardish 100 miler, I would only use liquids, probably 4 bottles with 3-400kcals of Superfuel in each would be my guess.

I don't think I have ever met someone who did not crave solid, real food and often greasy food at that after a certain period of time/miles IRRESPECTIVE of pace. At the other end of the spectrum are riders who only eat "real food" during rides. The shorter and more intense the ride, the longer before it that I will eat and the less intake or none during it. Even on a tour where I might be only doing 80-100 miles per day in hilly terrain, it becomes more than challenging to replace all calories and you lose weight and at some point or at least in my experience, you can throw anything into the blast furnace. Something changes. You crave fat and protein. And you do not get the upset tummies. I have talked to others who say the same thing. I understand you have not experienced this.

MoAlpha

Makes sense to me. You need fat and protein over a period like that and you couldn’t do it if it shut your gut down.

Carbonfiberboy 

No, I haven't. However, I['ve never ridden as long and hard as you have. I was never fast, just steady and didn't stop for long. Touring, I ate out of the bar bag, had a decent breakfast, not too much volume, a light lunch, and a normal dinner. Never used a carb drink touring. My longest tours were about 10 days. I might have lost a little weight, but never weighed myself. Not enough to matter much anyway.

typ240

…the issue I have is not drinking often, I could go for 30-35 miles without a sip. I then overload and drink towards the end to compensate, which is too late by then!

loggie24

Drinking enough was always my biggest problem lol