I am new to this and have questions about adding calories for longer events. I do long runs at comfortable pace on empty stomach in mornings. During my last couple of three hour run, I started eating after an hr or so and had ~150 calorie/hr by eating chocolates. Longest that I was ever out was for a little over 6 hr and I had a gel every 40-45 minutes which is around 150-160 calories/hr.

Do I need to have more than 150-160 calories/hr if I go longer than 6 hr. If so, how much more? At what duration should I start doing so? In your experience, is there a relationship between amount of bumping up in calories required based on duration of event? If I want to go out for 6-7+ hr, how should I handle calorie intake?

If by chance bhearn is reading this,

I read your race report for a loop course in crissy field where you mentioned that you took 100 cal/hr in that race mainly due to change in your diet. I have changed my eating habits a bit lately. I eat more fat and less carbohydrate than I used to. I do not have experience in running longer. So I can not say anything performance wise, but I have noticed that I feel different in day to day life. I used to get cranky when getting hungry. My wife could tell that I am hungry and was acting diva because of that. But lately I do not feel like that. I am guessing it is because I am eating more fat and less carbohydrate lately. What do you think based on your experience for doing this for long time, if I want to go out for 6-7+ hr, how should I handle calorie intake?

Most people who run 100s will try to get in somewhere between 250 and 350 cal / hour, I would say. Once you get past marathon, you are definitely burning through all your glycogen, and it becomes a question of fat burning rate vs. calorie intake rate. After that, it's very individual. If you run slower, you can burn more fat, and need fewer calories. If you have trained low-carb high-fat, you'll be able to burn more fat at a higher intensity, but your ability to burn carbs efficiently may be impacted. There's really no getting around just going out there, trying stuff, and learning what works for you.

 

Oh -- and it's not really quite as simple as "it becomes a question of fat burning rate vs. calorie intake rate", either, because unless you have trained LCHF, your brain needs glucose. Without it, you bonk. Once you've burned through your glycogen, you have to get that from fueling (plus some small amount from liver gluconeogenesis). Your brain can't burn fat (it can't get past the blood/brain barrier). If you have trained LCHF -- at least, so the story goes, and it's consistent with my experience -- your brain becomes very good at burning ketones, and your liver becomes good at turning fat into ketones to supply it. You become bonk-proof.

 

If you are interested in learning more about LCHF for runners, I'd recommend Volek and Phinney's book:

 

http://www.amazon.com/The-Art-Science-Carbohydrate-Performance/dp/0983490716

Thanks for your response. Trying stuff makes sens. I did a l little longer than 4 hr run this weekend where I started taking calories after an hour and took ~142.5 cal/hr. I was thinking about taking more calories next time and see how it goes.

The fundamental reason for confusion is that I am not sure what should I look for

1. Should I try to take minimum calories and train my body to adopt? OR

2. Should I try to take maximum calories and train my body to adopt?

The fundamental reason for confusion is that I am not sure what should I look for

1. Should I try to take minimum calories and train my body to adopt? OR

2. Should I try to take maximum calories and train my body to adopt?

Actually I think that's an interesting question. But it has to start with, what are you training for? What are your goals? For me, trying on LCHF for size, one of the supposed benefits was the ability to get by with less fuel, thus simplifying one aspect of the race, and giving increased blood flow to my muscles, with less digestive load. But typically, fueling rate is one limiting factor in ultra performance, and if you can increase your fueling rate through training, in principle you can run faster. For anyone on an ordinary diet training for their first 100, I would definitely encourage them to try to take in a lot of calories while training.

Fueling is not the secret to finishing 100 miles.  Yes, it is a part of the equation, but training, pacing, and attitude are equally important.  

Agreed. However, GI issues are the #1 cause of DNFs in 100s.

http://www.irunfar.com/2014/06/2014-medicine-science-in-ultra-endurance-sports-conference-report.html#GastrointestinalDistress

I think bhearn and flatfooter each have solid advice.GI issues or nausea  will both take you out. Gels and liquids will only take you so far. Unless you are the bhearns of the world. Mile 20 in my 1st 50k an oz of banana would not stay down. Liquids and gels for 11 miles. Pistol 100 nausea at mile 90. Gels were like eating glue at this point. Another runner hit the nausea button at mile 50. The joy of ultras. Test out different foods. On race day none of them may work. GI issues on a night 12 hour. When poop falls in the woods does it make a sound? Remember I am not in either of their leagues.

From my experience, fueling is also a matter of intensity of the run, and this usually depends on the terrain and the trail. You can't always chose the intensity, especially on very hilly (20,000+ ft elevation gain), steep, technical courses. You may be forced to put in fairly high intensity just to keep going on such courses, whereas on flatter, less technical courses, you may chose to "relax" on some stretches to conserve energy.

When you run (not walk) at comfortable intensity ("forever pace", or a bit faster), you need far less energy than when you walk up hills on rooty, rocky, sliding and slipping technical trails, or if you have to climb over boulders frequently along the way. Your tolerance toward different foods might also change depending on intensity.

I found for myself that I don't tolerate most solid foods on long distances (50 miles or longer), just some melon, banana, grapes, or potatoes. The rest I have to supplement with liquid foods and gels, and I found that high fat does not work for me (it does not work for me in normal life, too, I have never tolerated fats well). E.g. Hammer's Perpetuem is too fatty for me for running, while their Sustained Energy (which has less fat) works well for me, as long as I dilute it well.

My intake on a high-intensity 100-miler is around 250-350 calories per hour, averaging 280-300 calories per hour over the whole race duration.

I'm lightweight (112 lbs), so this is quite high. It might be way too high for you, or it may be just right. Like the others said, food choices and calorie intake are highly individual.

Trying to force your body to adapt to a certain food regime is pointless in my opinion. Rather work with your body, and what it naturally is most inclined to "adapt to", or work with. Going LCHF can actually compromise your health long term, and possibly even short term (does not mean it has to, as everyone has a different tolerance level for different diets, but statistically, it's not a good option - always keeping in mind that "high carb" means something different to everyone anyway, the term is not defined).

I found that as I adapted to running longer distances, I needed less food. While for my first half marathon I needed gels and a sports drink to get through the distance, I now have no problem running up to 3 hours without any food, just water. That said, in a 100-mile race, I start taking in food (Sustained Energy and gels) during the first hour already, to preserve glycogen, and to give the body a chance to adjust between burning food, glycogen, and fat. How the body uses the different energy sources is a matter of genetics, and of training, so there's a highly individual limit to "forcing the body to adapt" - it works only within your genetically given parameters anyway. If your genes allow it, the LCHF training might be highly effective for you, and you will see huge benefits, but if your genes aren't made that way, LCHF will give you only minor effects, despite all training.

Studies show that caloric intake on long distance races varies a lot, but generally people eating around 240-360 calories per hour statistically have the best chances of succeeding. That said, the studies also show that there are runners who eat far less, or far more, who also succeed. If I were you, I'd try to do a training run on higher intensity, and on a trail that is similar to what to expect in your race, and see what happens, if you can go with lower caloric intake, like you do now, or if you have to eat more. The higher intensity runs will also show you which food you tend to tolerate well, and which ones to eliminate or stay away from at an aid station. This information will be more helpful to you than trying to force your body to adjust to certain regimes.

"I used to get cranky when getting hungry. My wife could tell that I am hungry and was acting diva because of that."

 

Maybe try a Snickers, "You're not you when you're hungry".

Sorry, couldn't help myself on that one.

Ha ha

 https://www.youtube.com/watch?v=rqbomTIWCZ8

I did 9:10 hour long run a week ago in which I took ~325/hr . I took one gel every 30 minutes and hammer perpetuem here and there(~8 scoops). I did not hit the wall and felt great energy wise.

The calories consumed are going to be a factor of the distance traveled and the weight that was carried over that distance.  For sure someone weighing 200lbs is going to burn more calories over the same distance as someone who weighs 145lbs.

Calculating out how many calories you are going to burn during the race is the easy part.  There are even calculators for that.

The makeup of the calories that are burned is affected by the pace on an individual level.  In basic terms, the easier someone is running the more readily their body is going to be able to burn fat to create the calories instead of consuming the bodies store of glycogen.  If you are running up around your lactate threshold or VO2 max, you will burning almost all glycogen.  If you are walking, you are probably getting almost all your calories from converting fat to energy.  In between those 2 extremes, each person is going to be somewhere in the middle.

Of course some folks could be running a 9:00 pace with almost no effort and be burning almost all fat.  Someone else might be close to the edge of VO2 max at a 9:00 pace and be burning mostly glycogen.

Climbing a big ascent at 1,000'+ per mile may be at a 15:00 pace, but that is going to take a lot of effort and may end up closer to the side of the spectrum that is burning more glycogen than fat.

If you are properly carbo loaded at the start of the race that will give you 1,500 - 2,000 calories of glycogen held in reserve.  Lets assume you are going at a relatively easy pace and that you are going to burn 50% fat and 50% glycogen.  At 145lbs you are going to be burning about 125 calories per mile.  At a 50/50 split you are going to run out of your stored glycogen at about mile 25.  If you are running at a higher effort you will "hit the wall" earlier because you will be burning more glycogen than fat instead of 50/50.  After mile 25 (and ideally long before mile 25 so your body has some time to digest even simple carbohydrates and get them to your blood) you are going to need to be consuming about 60 calories per mile for the remaining 25 miles.  Your glycogen reserves are going to be about 1/2 what you need.

I would take that 1,500 calories you are going to be short and divide it up by the entire race, that way you don't ever get too close to running out of glycogen until the very end.  That comes down to 30 calories per mile.  At a 15 minute pace you would need to consume 120 calories every 4 miles or every hour.  Gu's are in 100 calorie packets so I would take one packet every 3 miles which would be around 17 packets and 1,700 calories.

All that is based on a 50/50 split of fat and glycogen being burned.  If your effort level is higher and it is closer to a 25/75 split, you will need 50% more calories consumed.  I doubt in a race situation you are ever going to be much under a 50/50 split, but some people are efficient fat burners and could probably get away with less.

Probably best to err on the conservative side and consume a bit more calories than you think until you figure it out.  Unless you want to "bonk".

My 2 cents, probably not even worth 1/2 that.  Nathan