There is one rule that decides whether your marathon stays a race or becomes a survival exercise. Take the first gel before you think you need it. Most Indian marathoners take their first gel at kilometre fifteen, which is roughly thirty to forty minutes too late. The carbohydrate that arrives in your bloodstream at kilometre seventeen was supposed to be there for kilometre twelve. Glycogen is not a savings account you can dip into at the last minute. It is a deposit you make at the start.
I have run enough Indian marathons to know how this story ends. You feel strong through fifteen. You feel strong through twenty. Then twenty-eight arrives and you remember every gel you skipped. The legs go before the mind goes, and the mind goes a kilometre later. The fix is boring and unromantic and it works.
When the first gel should actually land
The published guidance is consistent across major sports nutrition position stands. Carbohydrate intake should begin within the first thirty to forty-five minutes of a marathon, not later. The 2014 International Society of Sports Nutrition position stand on nutrient timing recommends thirty to sixty grams of carbohydrate per hour for events lasting over ninety minutes, with the first intake before the second hour begins.
Translate that to running. If you are a four-hour marathoner, your first gel should be in your stomach by kilometre seven or eight — between thirty-five and forty-five minutes into the race. If you are a five-hour marathoner, your first gel is in your stomach by kilometre seven, which is around forty minutes in. The clock matters more than the kilometre marker. The clock is when your liver runs out of stored carbohydrate. The kilometre is incidental.
What happens if you wait until you feel hungry
By the time you feel the dip, glycogen depletion has already crossed the line where downstream performance falls off. A 2010 review in the Journal of Sports Sciences described the lag between ingestion and bloodstream availability — gel carbohydrate takes roughly fifteen to twenty minutes to reach the working muscle. The gel you eat at the moment of need helps the next twenty minutes, not this one. Eat ahead of the dip. Always.
The Indian context: Tata Mumbai Marathon and warm-weather fuelling
The Tata Mumbai Marathon is the largest Indian marathon and the most common debut marathon for Indian runners. The race starts in the early morning humidity of Mumbai in mid-January — typical conditions at flag-off are twenty-two to twenty-five degrees with high humidity, climbing to twenty-eight by the finish for the back of the pack. Warm conditions accelerate carbohydrate use. Research from the Korey Stringer Institute on exercise in heat shows muscle glycogen depletion is faster in warm conditions than in cool. The Indian marathoner needs gels earlier, not later, than their European or American counterpart.
How to time the rest of the gels after the first
The first gel is the anchor. The rest follow at roughly thirty to forty-five minute intervals. For most Indian marathoners running four to five hours, that means five to seven gels across the race. Distribution matters as much as timing.
The forty-minute spacing rule
Take a gel roughly every forty minutes from the first one onward. This puts your second gel around kilometre fourteen to fifteen, your third around twenty-two to twenty-four, your fourth around thirty to thirty-two, your fifth around thirty-eight. The exact kilometres depend on your pace. The principle is steady drip-feed. The 2014 ISSN position stand recommends thirty to sixty grams of carbohydrate per hour. One gel is typically twenty to thirty grams. Two gels per hour is achievable for trained marathoners. One gel per hour, supplemented with sports drink at aid stations, also works.
The water rule that nobody talks about
Take every gel with two to three sips of water. Not sports drink. Plain water. Gels are hyperosmolar, meaning they pull water into the gut to dilute. If you take a gel with sports drink, you double the osmolality and the stomach lining responds by extracting water from the bloodstream. This is one of the major causes of mid-marathon gut distress. The 2013 work from the Australian Institute of Sport on race-day gastrointestinal symptoms identified gel-plus-sports-drink as a leading trigger. Plain water. Always plain water. See our fuelling library and the nutrition guides for adjacent reading.
What to practise before race day
The gel that goes into your stomach for the first time on race morning is a gamble. Every gel brand has a different sugar profile, a different consistency, a different flavour. Some sit well. Some do not. The marathon is not the place to find out.
Long-run rehearsal
For the last six to eight weeks before race day, use your long runs as gel rehearsals. Take the exact gel you will use in the race, at the exact spacing you will use in the race. If you plan a gel every forty minutes in the race, do that in training. If you plan to use the on-course gel — most Indian marathons including Tata Mumbai provide gels at certain aid stations — practise with that brand in training. The 2020 review in Sports Medicine on gut training in athletes documents measurable improvements in gut tolerance with eight to ten weeks of progressive carbohydrate exposure in training.
The morning rehearsal
Practise your race-morning breakfast and pre-race gel at least three times before race day. The pre-race gel — taken five to fifteen minutes before the gun — is one of the highest-leverage carbohydrate doses in the race because it tops off glycogen without the running-while-eating coordination challenge. Most marathoners ignore it. They should not.
What to do if a gel doesn't go down
Sometimes a gel will not stay down. Heat, pace, dehydration, or just the body having a bad day. The decision tree is simple but most runners panic.
Switch the form factor
If the gel triggers nausea, switch to sports drink at the next aid station. Most marathons offer electrolyte mix. The sugar profile is gentler on a struggling gut, and the fluid helps offset what the heat has taken. The carbohydrate dose is lower per serving — typically six to eight per cent solution — so take two cups, not one.
Slow down briefly to let the gut process
Gut blood flow drops during running. When the gut is struggling, dropping pace for five hundred metres routes more blood back to digestion. It is a small tactical loss that prevents a larger strategic collapse. The 2013 AIS work identified pace surges as a primary trigger for gut distress in well-trained runners.
The clean next step
Marathon fuelling is one of the few race-day variables you fully control. The first gel is the anchor that holds the rest of the strategy in place. Plan it. Practise it. Don't romanticise running on empty — it is not character, it is suboptimal physiology. Build your race fuelling plan into your weekly training using the STRIDD plan generator, anchor your pace decisions in the calculators, and return to the Running Lab for the next chapter of race-day strategy.