Nutrition for Long Distance Running

I have always believed that a good training cycle & a great race is a combination of these factors

1.Consistent Training



In today’s post, we will discuss the importance of nutrition in training & racing. Before we discuss about nutrition in detail, one cannot run/race a marathon or put up a solid performance without working on their nutrition. Lack of nutrition will lead to a sub-par performance.

I still remember someone coming to us during a Sunday long run about 2-3 years ago and he threw a random challenge saying that I can run a marathon even without drinking any water. Can you?

I also see a lot of people mentioning on social media that they dont take any nutrition at all during training/racing. When I see such people , I am strongly reminded of the scene from Thillu Mullu, where Thengai Srinivasan says “Adulu Enna Perumai” ( roughly transalates to, what’s so great about it?)

When someone says, I dont eat/drink anything during a marathon , “Adula Enna Perumai” 😀

Before we get into the specifics, we need to understand that fueling and hydrating are completely different and not to be confused with one another. Hydration is replacing water/electrolytes that you lost. Nutrition is fueling your body to perform optimally. Both co-exist and missing out on any one also can hamper performance


Every time, we do a workout, our body burns energy & to workout/run for hours together, we need to constantly fuel. Unlike a vehicle that runs on a single fuel , like petrol/diesel, our body can fueled by carbohydrates and fats. For an efficient runner with a good aerobic base, the body is likely to burn more fat than carbohydrates. For a new runner/beginner, our body is more likely to rely on carbohydrates. The source of fuel is based on the exercise intensity. The lower the intensity , lesser the carbs & vice versa. However this cannot be a universal rule & it depends on the fitness level of the individual.

If you are racing a marathon/HM, you are most likely to run the race at 80% -90% of your threshold HR/pace which means your body is most likely to burn more carbs than fat. While fat adaptation and aerobic base building is essential to run a good marathon, it is practically impossible to run your best race/PR without any carbs. Carbohydrates are not bad for you. They are your best friends. Instead of worrying about your macro nutrient ratio or overdoing it by sticking to fad diets like paleo/keto, improve the quality of your macronutrients. The body needs all macro nutrients & hence dont force fit your body. It is not good on the long run


Our body can approximately store about 2000 calories of carbohydrates & interestingly, fat reservoirs are about 10-20 times that of carbs. A marathon is probably run 80-90% aerobically & the rest anearobically. Hence it is very important to set a good aerobic base & also work on nutrition while training. While our body uses both fat & carbohydrates as fuel, the body does not have any switch that can be used to switch between fuel. Have you ever wondered why most runners hit the wall at 32kms?

Assuming a runner burns about 60-80 calories per km, they are most likely to use up all their energy reserves by 30kms and hence they hit the wall. Unfortunately, the body cannot start using fat reserves after they run out of carbs. While the body uses more carbs at higher intensity, we cannot predict the ratio of fuel as it depends on the fitness level of an individual and hence it is very essential to experiment during training.


1.Easy Runs – I recommend to get used to running on fasted state immediately after getting up for shorter runs or just water for easy runs less than 45 minutes. When there is no fuel, our body gets used to burning fat. This is also one of the reasons, why most runners lose a lot of weight when they ramp up mileage ( They may also lose a lot of muscle, when they dont fuel well. But that’s a topic for a different day)

2.Long Runs/Speed Work – I recommend a combination of water & a good electrolyte to replace the salt that we use. HAVE YOU USED THE UNIVED SALT TABLETS. They are a staple in my training

A common question that I get is -how much do I drink? For everyone who needs to know the answer, I suggest everyone to do the SWEAT TEST. As soon as you get up, empty your bowels & weigh yourself without drinking anything ( Weigh yourself preferably naked). Go out for an easy 45 min- 1 hr run and measure yourself again after the run immediately. The net loss in weight, is the amount of fluids that you have lost. Do not use any fuel for this run. If you used some water during the run, use that in your net calculation to understand how much water you have left.

Net Fluid Loss = Weight before the run + water drank during the run – Weight after the run

If you sweat a lot, increase your electrolyte intake, typically 1-2 salt tablets every hour. Again this is not a universal rule. Experiment in training and understand what works for you


1. Easy Runs/Long Runs – I love to do all my easy runs on fasted states with just water & salt tablets . Most of my easy runs are not more than 2 hours long and hence water+salt tabs just works fine. On bad days, when I am not feeling like it, I prefer to carry some fuel. I personally love the UNIVED ELITE DRINK MIX that has 45gms of carbs in one sachet. I am a big fan of the ORANGE TWIST flavour as its very mild and it works perfectly.

For those who are new to fasted runs, I would recommend that you take it slow and steady with shorter runs preceded by good rest/sleep without overdoing it. Listen to your body and be smart. Do not blindly do it everyday because I suggested it. Patience and consistency are the biggest virtues of a marathoner

2. SPEED WORK – INTERVALS/TEMPOS/LONG RUNS @ GOAL PACE – I mentioned earlier that our body can store a max of ~2000 calories. Assuming an average runner weights about 60-70 kgs, the person will approximately burn about 60-70 calories per km, an average runner will roughly burn 2500- 2800 calories during a marathon

Interestingly, our body burns more than 60% of our TDEE (Total Daily Energy Expenditure) everyday, even without us blinking an eye for our regular bodily functions such as blood transport, regular functioning of organs etc. Hence the amount of fuel available on a fully carb loaded state is not 2000 calories. It is much less than that & of course depends from individual to individual. Assuming that we have about 1000-1200 calories alone for usage, one needs almost 1200-1400 calories more to satisfy the energy loss that we go through, while running a marathon.

Can you fuel that much- Not everyone can do it. A normal gel is about 100 calories. The UNIVED ELITE GEL is about 190 calories. Not all runners can eat so much on the run. Hence it is extremely important to

1.Do a lot of runs @ marathon pace & train the body to burn more fat at marathon pace

2.Fuel on the long run with carbs and experiment during training.

The best cue that I can give anyone is to start fueling before you feel hungry. During my build up to Chicago, I always felt hungry during my long runs because I was trying out the new products. I took my time to work on my nutrition but it worked out perfectly for the race. I felt so strong throughout the race & didn’t feel hungry at all. I had 5 elite gels & 3 Orange Twist Drink mixes

In a nutshell, one needs to fuel for these runs, because the body works at a faster rate ( anaerobic). Do not do these runs in a fasted state. The body will start tapping on reserves and there is a chance of losing muscles as well.

While there are lots of carbs option available for fueling, liquids/gels work the best because it mixes quickly into the blood stream & supplies the necessary energy. Also, its very convenient to carry. Technically speaking, even bananas are a good source of solid fuel. But how many bananas can one eat on the run. How do you carry bananas?

Hence from a convenience perspective, I would suggest that gels/drink mixes should be used for speedwork/long runs. While there is no thumb rule again, I would suggest using a gel for every 40-45 mins to start with/ 500ml of drink mix every hour. You can start with this option and slowly figure out what works for you!!

P.S : Please be sensible & dispose the gel/drink mix sachets properly #USETHEBIN

Please understand that there is no universal rule as the fuel depends on the exercise intensity and the fitness levels of an individual. Hence it is important to experiment in training & understand how your body works before racing.

Thank you for patiently reading . Hope you can work on your fueling based on this blog. Feel free to write to me at for queries. For those who have patiently read this, read on to know my usual fuel routine


EASY RUNS/EASY LONG RUNS – Water+ Unived Salt Tablets

INTERVALS – I like to find a fixed loop for this. I use the drink mix for intervals. I pre-mix them the previous day and keep my bottle at the designated place. Post warmup, I ensure to end the first lap of interval at the designated place so that I can use it during the recovery phase. Whenever I feel like hydrating, I ensure to end the interval phase & start the recovery phase at the designated place . Works perfectly for me

TEMPOS/LONG TEMPOS – I typically eat a banana before short tempos and carry water+salt tablets. I use a gel every 40 mins. For long tempo runs, I typically have a mild breakfast 2 hours before the run ( PBJ sandwich/oatmeal & I have a gel 15 mins before the run). I use a gel every 30-40 mins depending on the intensity of the run & based on how I feel. My personal favourite is the UNIVED Elite gels (Vanilla Sea Salt & Double Espresso) & the ORANGE TWIST drink mix. I alternate between gels & drink mix as its easy on the system and also having different flavours do not cause any fatigue on my tummy. The Unived Recovery Mix is a staple in my training & I use it after hard workouts to recover quickly.

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