What should I consume during long distance runs?

Of late, there are some typical ways my conversations go with people training for their first marathon (or half marathon in some cases). 

Person 1: Jagan, I am going to attempt a 20k run today as I have registered for a HM in 3 months.

Me: Wow, congrats! So what is your nutrition and hydration plan for today?

P1: Oh, I have a 1L bottle of water in my bike, will access it every half hour.

Me: That's good. What is the nutrition plan?

P1: Electrolytes? I have a few Glucose bolts chewable tablets. Hope that should help me sustain.

Me: .... 

Another day, another long run

Person 2: Jagan, today is a 30 k run for me as per the CR training plan.

Me: Wow. so what was the previous long run? How did it go?

P2: We had a 28 k a couple of weeks back, did in nearly 4 hours. I had to take more walk breaks after 2 hours. Weather was not supportive.

Me: Oh. How many km did you complete in 2 hours?

P2: I started strong, did nearly 17 km in 2 hours!

Me: Nice. What did you eat?

P2: I had a heavy dinner the previous night.

Me: ....

Yet another day, another person

Person 3: I always seem to hit the wall at 2 hours. Irrespective of whether I run at 7 pace or 8 pace, I get really tired at 2 hours

Me: Happens. What do you carry when you run for 2 hours?

P3: I carry my small handy bottle. I have another bottle in my bike and I refill water every 45 minutes to an hour. Also, I have tried energy gel also once, did not help.

Me: Is it? When did you consume the gel?

P3: I think around 1:45 minutes or so.

Me. .....

Guess you got a hang of it now. People who are attempting to run long, graduating from their 1-hour and 2-hour long runs to slightly higher times tend to assume that their body will automatically get used to running long and they just need to keep themselves hydrated (plain water, that too). Unfortunately, it does not work that way. This blog is for those who want to get better at long distance running - ideally marathon distance or more (but will help those attempting their maiden HM and TM too). Let me break what you take during your run into two categories - Hydration and Nutrition.

Hydration

The general guideline is to drink around 300 ml water every 25-30 minutes. I say 300 ml coz all of the handy water bottles with straps that we carry during runs (or chotta bisleri bottles) are 300 ml. So, you should be reloading these bottles (or changing them) every half hour if not earlier. This is regardless of whether you feel thirsty or not. Do not wait for thirst to drink water. Keep sipping at regular intervals (do not gulp water at the 30th minute because I told you to finish 300 mL in 30 minutes). If your run is going to extend more than an hour, you have to add electrolytes to your hydration. You can choose to use any of the market products (like Fast and Up Reload) or you can use lemon/salt mixture. Note: Lemon/salt mixture does not replace all the salts that we lose. It replaces only sodium. Salt tablets are something that we can add if our sweat loss is high. The overall hydration includes your water and electrolyte liquids.

Nutrition

Your body can only store enough glycogen (the stored form of carbohydrates) to fuel about 60-90 minutes of running. After that, you need to consume external carbohydrates to keep your muscles working. Here again, we cannot wait for the 90 minutes to end and then replenish when the energy stores are dangerously low. You got to be ahead of the ball and start adding those carbs into your system after your first hour, and keep doing it regularly. You can aim to replace around 50-60 g of carbs so that you have the energy to go on. A typical energy gel packet has 25 g of carbs, you may take one every half hour. If you are a natural food person, the easiest option is banana. Here is the banana v gel comparison (Thanks Gemini).

The other easy to carry option is Dates. You can take 2-3 dates every half hour and wash it down with water. The advantage with dates is that in addition to being easy to carry, they also have a good amount of potassium, thereby reducing the need for salt tablets. Dates sprinkled with salt may give you the sodium boost too! Today, I got to learn (thanks to Gopinath Nagarajan) that honey is a good fuel source and has fast-acting carbohydrates and compares equally to gel packets. The problem though is that it is difficult to carry honey to keep replenishing. So, if you are a "natural foods" person, maybe having a ziploc cover with dates soaked in honey may be a good choice with an occasional half banana sometime mid-run.

If your hydration and nutrition plan is proper, it certainly will not make you a faster runner (which is the domain of training) but it will ensure that you realize your potential when you do the long runs. If this foundation is not laid properly, and you try to follow your long run pace as given by your coach, you are bound to fail. Another important aspect is that if you are training for a race, start this hydration/nutrition strategy trials at least 6-8 weeks before the race. Experiment with different methodologies as described above and arrive at the best one for you. Ensure that you are not surprised with anything new during the race!

Hope this will help you ace your race. Good luck! Drop in your comments if you have any other tested methodology that has worked for you!