Before you read this, please check out the latest link on 5K and 10K pre race nutrition. That is kind of fundamental, before you understand why food consumption during a marathon is unnecessary for most athletes. Also to grasp the fundamentals of a totalitarian aerobic training system, please click on the second link of the MAF method.

  1. https://scorum.com/en-us/running/@traillevi/5k-10k-race-nutrition-and-hydration

  2. https://scorum.com/en-us/ncaa/@traillevi/the-maffetone-method-running

Marathon is very aerobic distance. Especially if we talked about a timeframe of 2,5 to 3,5 hours and it really should be. Under that timeframe, it is still dominantly an aerobic event, but fat mobilising and fat utilising greatly decreases and those paces and pace changes burn up brutal amounts of glycogen, that is for sure.

Before we start, I am giving you some date about Mark Allen. He won ironman KONA 6 times. He used mixed principles of rest and fast running. Worked here and there with Phil Maffetone.
His 8km MAF aerobic test pace was 3:20/km at the age of around 30 at 155bpm heart rate. He stepped into the realms of injury free long term development so he could often add +5 to his Max Aerobic Force heart rate.
So again running 8km at 155bpm at 3:20/km pace ! If you immersed in aerobic training science, you'll see a non-linear decrease in pace / heart rate and time spent at those. However, he could have been able to cruise an open marathon anytime with no ill health consequences at the HR of 135 to 150 under 3 hours. I mean running 40seconds slower per kilometer what is 4minute pace would be a 2:48 marathon. Probably he would have been averaging 140 heart rate for the entire event.
When you are a healthy 30 year old and your aerobic system is so widely developed, your max HR is around 200. Imagine that he had still 60 beats of HR reserve.
Of course cycling gave him aerobic boosts and swimming improved his mobility and structural integrity, so running was greatly supported by auxiliary activities, but it shows the possibilities.

So here is the thing. If instead of focusing on a goal pace, we focused on heart rate for most of our training, worked up to a necessary distance, incorporated the downhill tempo runs and uphill sprints, we should be totally able to run a low heart rate sub 3h marathon. It is more complex than that as health is, but that is the base. We should be able to run a marathon in aerobic heart rates for the entirety of the race, not taking in anything but some salted or plain water, depending on the actual individuals and the environment.

Having correct daily nutrition is key. Incorporating, some correct intermittent fasting and fasted runs are also key to success. It has to however carefully balanced out. You are an athlete so negative energy balance is unacceptable for constant mid to high mileage runners. This means that if you fasted, your needed calories should be compressed later in the day. It is called a compressed feeding window. However, if on those days you focused on fats and an early evening caloric carb backload, it could be done by more athletes.
Look at the Kenyans. Their volumes and intensities are enormously high. In the morning before the long haul aerobic group workouts, they ingest a bit of coffee and sugar. They go for 10 to 20miles. Comparing energy utilisation and intensity between them and a regular runner, actually a regular runner would not need the sugar part as he burns less than half of the calories that a Kenyan runner would do. Later on they eat light with little meat. They workout again at the afternoon doing their intervals and faster running and then they eat that giant bowl of ugali. Most of them eat not more than 2 times a day. They also often engage in hard physical labour, like in local agriculture or construction work.
During a marathon they consume energy drinks, what is very often just sugar water, or a special blend of corn and water, only in the second stages of the race. Very often however, they just listen to their bodies and skip water, skip food, skip the aid stations.

Marathon race nutrition

To gather my thoughts and arrive to our subject, yes we'll talking about gels, chews, energy drinks and powders and the advices of sports nutrition "experts" and coaches not immersed in health studies.

Have you ever seen those runners having a fuel belt with 20 gels around them ? I also did see them washing them down with coke and banana slices ! Yes with more sweet stuff.

Those gels are all sugar ! Regardless that is maltodextrine, dextrose, sucrose, glucose, fructose, super starch, whatever, it is only sugar. Some of those have vitamins, minerals, stimulants, adaptogens, herbs and more.
When running a marathon, most people are so stressed out, that even simple water might upset their stomach, still they are forcing down those goowy, chewy, sticky substances. No wonders that we see so much bonking, so much cramping, vomiting, walking and so many dreams crushed.

Marathon is a very special distance. It takes a lot to master, if it was possible to master. I am a quiet okay runner with 15min 5K, 35 10K, 1:15 half and so, but my marathon is crap, 2:52. I am more likely built to faster races, or very long ones. That 2,5 to 3hour range at those efforts is just not for me. However, when I tuned in my nutrition finally, well actually tuned out, this is when my times slowly started coming down. My very first sub 3 was, when I took, one single honey packet with me, of about 75 kcals. I used it as insurance policy at the 37km mark. The next two times I had nothing with me, and I had only some bananas and a squeezed orange slice. The latest and last I did about 3 years ago was the fastest, where I drank a half cup of coke at the last aid station, what I spit out immediately and washed my mouth out with water. Since then, I more likely focus on ultras, but Last year I went on a 40km MAF run around the track. I started out MAF - 15 and as time passed by, I increased it up to MAF. I averaged 4:15 pace what is a 2:59 marathon pace. I consumed absolutely nothing. It was 27°C cloudy. No water, no salts, no sugars. I had no pee stop, no aid station disturbance, nothing. 100 laps around the track. It was extremely eye opening.

So, what those gels do to your body is extremely harmful. They raise blood sugar and drop it below homeostatic levels afterwards. Especially if you had a sad-bad diet.
Together with high efforts, they mess up your gut lining and overwork your pancreas. Some of these sugars come from sources of corn or wheat or other cereals ! If you had a micro sensitivity, you might develop a very little allergic reaction. You get slightly congested, so your nose breathing will be hindered. You start breathing through your mouth using less diaphragm and more intercostals and other breathing muscles. Bang, you have a side stitch, a back pain, a tight psoas or calf and so. Yes, the diaphragm helps providing intra-abdominal pressure, what is the base of your trunks stability. Can you see how bad breathing technic and an upset stomach can completely destroy your posture and running form ?
Better be hungry but economic !

Sugar also effects the brain. Instead of having that mellow efficacious cruise mode and just floating along, you switch between states of extreme fun and low motivation. During ultra marathons it becomes very visible. We can see so many abandons for no particular reasons. Bad decisions are often made during sugar highs and sugar lows.

Practice

For sure, that this needs practice. This needs daily life practice and training application. If you were snacking around the clock and your meals are mostly bagels, juices and sparkling drinks with an evening frozen TV dinner, well your first goal is to clean up your diet and attitude ! If you are used to drink a pre and post workout shake, guess what, it is totally unnecessary. To develop a strong gut, it is better to avoid food a couple of hours before workout and after. Depending on the size of the meal you had and the performance you want to pull off during the actual workout, you might want to wait even up to 7 or 8hours. I run every morning as I cannot do so at the afternoons, however that is the best time to do so. Around 15 to 17pm. The body is more relaxed, more mobilised, more stretched out, more fuelled, just ready to go. Many coaches uses this in their mantra: "No hard running at the morning ! "
Kenyans do their aerobic longer prep-runs in the am and really hit the track at the afternoon. Often they wake up at 6am and they are already running at 6:45 ! Water, coffee, have a s..t, light mobility and off you go !

Day temperatures are also higher, what is important. You just cannot have a proper fulfilling meal at noon and expect to run a hard track session 2h after. The way to go is first of all to be healthy and heave a healthy lifestyle and blood sugar regulation. You go out in the morning for a walk, a jog, a bike ride, just to move your body around.

Depending on the nature of the afternoon workout, you have meal at around 8am. If it was a long run, constant tempo run or a hike/run combo, I go fatty. 1 or 2 avocados, can of sardines, olives served on a lambs-lettuce bed. Maybe even a slice of beef.
If it was a hard track interval day, I would go carby. Porridge, cooked in water, with no butter in it. Served with dates and raisins, a banana, sprinkled with coconut sugar and loads of cinnamon, all served on a giant swiss-chard leaf. If you flooded your system with fats before a hard speedy run, you'll see and realise, that your absolute edge is stolen !
8 am as I said. 7 to 8hours before that break through set of 400s ! I don't care, if I feel hungry before hand. I drink plain and salted water during the day and that is it, then execute with no issues and no upset gut.
So eating some, might help at the beginning of a performance journey. A little cup of tea, with one or two dates and some spirulina caps. Essential amino acids, glutamine caps, l-carnitine caps... At least 60 minutes before.

After a difficult workout, your body is upset. It is stressed. It is often a mess. Very often in 30 to 60 minutes the body goes through phases of heat, cold, alarmed, calm, hiped up and more. If you ate a giant meal, it won't necessarily be properly digested and will make you very sleepy as blood flow to your brain will be extremely limited. Also digestion will be totally hindered as the body is not ready yet ! It wants to descend back down to a homeostatic state !

Carb backloading can actually happen at the evening meal 5-6-7-8 hours later. You don't need that much of food to feel better and to recover. Actually to get out the most hormonal response like elevated growth hormone production, you better go with nothing but electrolytes and water.
One trick is to take 15g of EAA. 5 each 30 minutes. Then at the 2hour mark you have a smoothie. 1 banana, 4 dates, 2 scoops of hemp protein, 1 teaspoon of cinnamon, couple of spinach leaves, blended in almond milk.
Often I have excess calories the day before a very important workout and the day after. On the day itself, I might be in a negative energy balance. No problems here !

Coaches - it depends on which - , also prescribe no more than 2hours of running at a time ! I think Daniels says, that runners has nothing to do over the 90 minute mark, as a long run ! It is a bit misunderstood. You still can have a 3 or even a 4 hour workout ! 30 minutes of mobility, 30minutes of track schooling. 15minutes of run warm up, progressing into a 75min marathon pace injected tempo run. 25minutes of cooldown and 25mintues of mobility and dynamic stretching. That is 4hours ! No issues here at all !
What we talk about is constant running. Let's say for a marathon, we should be running definitely under 4 hours ! Our long run is mostly in the 90minute mark, maybe over stretching once or twice to the 120minute one. There is no marathon over 4 hours. It is freckin' unhealthy to pound the road, for that short of a distance that long. Shuffle long runs of 3hours in preparation for a 6hour marathon is non-sense. Better loosing the weight, better get healthy, better to do 5ks, 10ks and maybe half marathons, till times come down and we can run properly as a healthy human should be !

Fine line between health and performance

Did you get the big picture ? We talked about training. We talked about lifestyle, health and daily nutrition. There is no gel talk. No powdered potions and magic pills here ! Your existence defines your endurance ! How you plan out your days, your food, your training, is entirely up to you. It is discipline ! The research to your journey has to be done by you. Would you want a body what can handle anything or a crippled old, inflamed cranky frame ?

If you had a strong marathon training and proper life, you might want to have one gel with you for insurance. You can find natural ones from honey, concentrated fruit juice, maple syrup and so. You might want to look into hydrogels.
Maybe with some salt in it. Otherwise, you can squeeze on orange in to your mouth, take a slice of banana, or if having a shock, a cube of white sugar as pick me up in the final 3 to 5km of the race.

We did not talk about pacing, but it is essential to get it right. Start out slower than goal pace. Progress into your desired speed. Hold it. Increase it slowly in the last 3 to 5km. Start the very first mile fast and you'll be on a total roller coster for the entire ride ! Guaranteed ! You can even loose 1 minute in the first 5km till you arrive to your goal pace. Normally your goals are flexible and have margins. You don't prepare for a 2:58.17 marathon. You plan to run a 2:55 to 3h one. Start out with a 3:15 pace for a couple of hundred meters and take it down to the 2:57 one in like 3 to 5km. Get your body into the motion into the groove ! This becomes more important if your warm up was missing elements or time ! The lack of warm up has very negative consequences. You need at least 15minutes. Before 10k races I go for 40minutes of warming up. Jog, move, jog, speed, sprints, jog, start line, race.
Decide your m-pace correctly. Train accordingly. Race properly.

We talked here to the average runner. High performance racing and training is different. It is disassociated from health.
However, many many even aged over 50 can run sub 3h marathons on nothing but water. They are lean, healthy and smart ! They recover fast and have no joint pain, not before, nor after ! You and anybody can do it ! It is only the question of discipline, habits, knowledge, passion and love !