Are you eating Oct 23-25?

This post is targeted at runners who are newer to marathoning. Veterans can feel free to skip this post.

A favorite running quote:
"The body does not want you to do this. As you run, it tells you to stop but the mind must be strong. You always go too far for your body. You must handle pain with strategy...It is not age; it is not diet. It is the will to succeed." -Jacqueline Gareau, 1980 Boston Marathon champ


Let’s talk about food for marathoners during the last 48 hours before the race: on the one hand there are benefits, and on the other there are potential problems.

A) Food helps fuel your marathon victory (benefit maximization)

1. “Carbo-loading” is the practice of eating a high-carbohydrate diet (carbs) in the days leading up to a race. Much of the information on the internet about carbo-loading is opinion vs science-based fact. Here’s a fact: taking in more carbs as a percentage of your diet in the 24hrs before a marathon can top off your liver and muscle glycogen stores right before the race (glycogen is the preferred raw fuel for human cells including muscles, but especially the brain). This presumably gives a runner an advantage through more readily-available energy (Dr. Timothy Nokes, Lore of Running). Note this does not mean eating more food than normal - it is just that carbs will be a higher percentage of your calorie intake relative to protein and fat
2. Eat breakfast the morning of the race. Be sure to include some protein in every meal including this one. Your mother and Kellogg’s were both right, breakfast is an important meal, especially on race day
3. Consume carbs during the race. Try to consume "quick carbs" that quickly digest: sports drink, bagels, gels, etc. Eat what you have been training with if you can (you have been eating during your training runs, right?)
4. The evidence is still mixed about any benefits of consuming protein during the race, though it is the latest marketing craze. There may be benefits for elite runners; that probably doesn’t include many of us
5. When runners say they “hit the wall”, it means they felt like a car that ran out of gas. Mile 17 is the classic place to “hit the wall” in a standard marathon, and it is because runners do not start consuming fuel early enough. Plan to eat or drink an appropriate amount of calories during the race, and start early. A good rule of thumb is to consume some calories at each water station (the fine print details below*)
6. Consider drinking the sports drink provided on the course. It's convenient and it's free. Many people adopt this drink as part of their running routine leading up to the marathon
   

B) Food is a runner’s worst nightmare (problem avoidance and mitigation)

1. Runners are significantly more prone to gastro-intestinal (GI) distress than athletes in other sports due to the bouncing their guts endure. Whatever is inside those guts during the race can easily make things worse. Let your own experience be your guide, everyone is different; some people really do have iron stomachs (while others only think they have iron stomachs). That said, the following are some things which are widely true for most people
2. New marathoners tend to be anxious at the start of their races and have more nervous stomach issues than veterans. New marathoners should be more cautious about what they eat than veterans. So if you see an experienced marathoner drinking a beer and eating raw eggs before the race, don’t assume it’s a role model you can safely copy
3. Fiber keeps food moving through your system and lowers your cancer risk. However this movement is exactly the opposite of what you want to happen on race day. Many people avoid fiber before a race (lettuce, broccoli, French beans, legumes, lots of carrots, etc.)
4. Trying any new food 48hrs before a race is begging for trouble. I’m just saying it, go ahead and eat the kimchi if you want
5. Avoid big portions of heavy protein with fat (beef, pork) 48hrs before the race. It tends to take longer to digest
6. Avoid unnecessary fat (e.g., Five Guys makes great burgers and fries, go there after the race vs. the night before)
7. Avoid quick-carbs for breakfast on race day. Old fashioned oatmeal with raisins: yes. Fruit Loops or Lucky Charms: no
8. Hopefully you have been eating in order to train your stomach during your long runs. Plan to eat the same thing during the race that you ate in training, it will help avoid tummy troubles
9. For the 24 to 48hrs before a race, when you are presented with interesting, exciting, maybe novel food, ask yourself "Is this thing I'm about to eat going to taste good enough to compensate for having to race between porta-pottys during the marathon?" Then eat accordingly

What I Eat

So runners have asked me what I eat. Some people drive defensively; for 24 to 48 hours before a race, I eat defensively. I go on a "white food" diet. If it's not white I try not to eat it (though I sometimes give in to temptation or simple logistics). I eat white rice (carbs), cottage cheese (protein), bananas (carbs), old-fashioned oatmeal (carbs), milk (carbs + protein), chicken breast (protein), etc. (unfortunately the white food diet doesn't include vanilla ice cream). Folks ask “Why rice?” Because nothing is gentler on the tummy – rice cereal and bananas are what we feed babies, what could be lower-risk? I once brought baggies of cooked rice to an ultramarathon and ate it along the way. It scored a zero for taste, digested quickly and easily, and gave me a good energy supply throughout the race.

Eat defensively and I'll see you at the race.



*The fine-print details for the metabolically inquisitive: a runner's body needs fuel to run. The most common reason for "hitting the wall" is that the runner's blood sugar drops (the runner becomes hypo-glycemic) because they have not eaten enough to supplement the body’s stored fuel they are using up.

Digestion and metabolic facts in 10 letters:
(a) Carbohydrates (carbs), proteins, and fats can all be used by the body as fuel. (b) Carbs are more quickly/readily converted to glycogen (which is the particular carb that muscle cells prefer). (c) 1g of carbs = 4 calories. (d) Runners burn roughly 100 calories or 25g carbs per mile. (e) A runner burns roughly 2,620 calories in a marathon, or 655g carbs. (f) A runner also burns fat stores albeit more slowly and the calculation of this is more complex. (g) A trained runner's liver stores 300g - 400g of glycogen after "carbo-loading". (h) The brain will prevent the runner from depleting their glycogen stores completely; I estimate based on what I have read that a trained runner has around 150g - 300g available to use during the marathon (let’s call that 8.25 miles). (i) A runner’s stomach can absorb about 1g/minute of liquid carbohydrate. (j) Consuming > 60g carbs/hr will slow the stomach's food absorption (Dr. Timothy Nokes, Lore of Running, p 209 and others, sources cited).

Many runners complete marathons without consuming any food. However there is solid scientific evidence that consuming food during exercise improves the exercise outcomes. For runners in a modern big-city marathon, this is usually drinking the race’s sports drink. As a practical example, many sports drinks have 50 calories per 8 oz. If water stations provide about 6oz of sports drink in an 8oz cup (37.5 calories each) and a runner consumes sports drink at each of the 12 MCM water stations, the runner will consume 450 calories during the race. This will certainly help to provide fuel for the muscles and to keep the runner's blood sugar levels up.

One more note: brain cells are very finicky eaters, they dine solely on glycogen. The brain is also very selfish and it appears that, as the body’s stored up glycogen runs low, the brain detects this low level and orders the other body cells “stop” to preserve its fuel supply. Runners likely experience that “stop” as the feeling “exhaustion”, and so runners stop running and burning up glycogen. Practical evidence for this is, after a period of time walking (maybe without even eating any food), runners feel better and can start running again. During this time the body has replenished some of the glycogen by converting body fat or protein and so the brain has cancelled its “stop” order. The stores get depleted rapidly this time and “exhaustion” sets in again. So exhaustion seems to be the brain’s way of preserving its food supply and therefore its ability to function properly. This suggests that humans can "run through" exhaustion as just a state of mind, but with some risk.