Running a marathon is a different experience for everyone. For some, it means conquering a mountain they once admired from distance. For some, it’s a spiritual experience liberating them from their morbid sedentary lifestyle. For some, it’s the destination of a long, arduous journey; A journey which, more importantly, changes the person for the greater good.

What’s common though largely is how to fuel a marathon. Based upon certain parameters, we can easily make a perfect fueling strategy for ourselves. It is first imperative to note that a clever nutrition strategy will never be limited to planning during the race or a meal prior to that only. An efficient nutrition strategy should be followed for months to make your joints more mobile, your muscles stronger and your fascia smooth as silk. Protein, good fats, calcium, magnesium, vitamin D and other vitamins are as important as the nutrients listed discussed below during your long term preparation for the marathon.

Moving on, the following is a do-it-yourself guide to fuel the key nutrients during the D-Day:


Water is perhaps the most obvious one but a critical component, nonetheless, for any efficient run: let it be a half or a full marathon. Depending upon hydration levels and body’s tendency to sweat, the point where you can get dehydrated can vary. The best way to find out if and when your body needs hydration is to measure your weight before and after your smaller practice runs.

According to this Review in Journal of Sports Sciences, if the body mass has decreased more than 2-3%, you need to rehydrate immediately for better performance. So for a 50 kg female runner, this translates into 1-1.5 Kg weight loss during that stretch of the run. How to use this info for a 21 or 42k?

If you have read anything on marathon pacing strategy, you would know that it is best to fragment your race into smaller parts to finish for a specific timing. It is best that you strategize your hydration points according to those pace points to ensure you are hydrating yourself regularly. Do not wait for that thirsty feeling. It’s already too late by then.

Coming on to the rate of water intake, The American College of Sports Medicine in its position stand on fluid replacement suggests water intake of 600-1200 ml/ hour along with carbs and electrolytes. This brings us to our other 2 important parameters.


Sweating is our body’s natural cooling mechanism and marathon running invokes quite a lot of sweat. Our sweat contains not only water but electrolytes as well. A key nutrient we lose while sweating is sodium. While running a marathon (or any endurance activity >2 hours), either due to just sweating or even due to excessive water intake, our body can go into Hyponatremia. So, it is better to have a salted drink vis-à-vis pure water. The optimum sodium concentration should be 10–30 mmol · L−1 (Link to Research Guidelines for Sports Drinks), depending upon sweating intensity, which roughly translates into 0.6 to 1.7 grams per liter.

Another key nutrient is potassium. If you’re drinking any sports drink or salted water for your runs and still suffering cramps, acute potassium shortage may be the culprit. There has to be a balance between sodium and potassium at cellular levels. Most professional sports drinks like Gatorade maintain that balance. If you are eating bananas (as offered in most Marathon fueling points), that should provide you enough potassium.

Another way to increase potassium intake is adding fresh lemon juice (potassium: sodium ratio for lemon is over 100:1) if you’re making a homemade salted drink. Although avocados are also a great source of potassium, they have high fat content making them harder to digest during the runs.


For half marathons and marathons, carbohydrates become even more important since you cannot fuel an entire run on your body’s glycogen stores. Failing to take appropriate doses during the event can result in muscle loss, fatigue and decrease in performance. According to this study, there is a dose dependent positive response to ingesting carbs while performing long duration endurance activities. But this is the nutrient people screw up most, either not taking at all or taking too much.

How much to take? Well, the research guidelines for endurance runs recommend it at 60 gm/hour which is the highest rate your body can oxidize a single carb source. But there’s a way to oxidize more carbs (and provide your body more energy). This research review proposes that through digesting multiple carb sources (most common being glucose + fructose), you can oxidize as high as 105 gm/hour. And the good news is that you don’t need to be in a lab to make such a multiple carb fuel source. Bananas have both glucose and fructose. For those relying on electral, gel, candies etc to get their carb intake, they may want to mix it up in with some diff carb sources.


With all the research based info listed above, you can fuel your marathon even without using commercial drinks with just bananas, water, salt and lemon. That being said, it is wise to not try things on the D-day itself. Experiment in the remaining smaller recovery runs. Also, there may be lots of fueling points offering different products but we recommend that you stick to what you’ve tried and tested on yourself earlier in your practice runs.

We wish you an injury free, memorable Mumbai marathon. We hope you blaze your way into the finish line.

Checkout these Marathon Trainers in Mumbai to get yourself ready for your next marathon: