As a Mechanical Engineer, I was always fascinated by automobiles. I
was intrigued by how a simple automobile engine converts chemical energy
of fuel into motion. Now that running is my newfound passion, I cannot
help draw parallels between running and automobiles. Fundamentally, the two are
very similar – both machines draw upon the energy from a fuel and convert it
into kinetic energy (i.e. motion). However, the choice of right fuel is far
more nuanced in the case of human running. This blog explores some key aspects
around the choice of right nutrients to ‘fuel’ an athlete’s body.
Recreational runners are often obsessed with the
idea of enriching their diet with carbohydrates and for right reasons.
Carbohydrates, after all are the energy giving food and are critical for
runners, especially long-distance runners. However, this obsession with ‘carb-loading’
at times leads them to neglect other important nutrients. An efficient runner needs right amounts of all types of nutrients – proteins,
carbohydrates, fats, vitamins, minerals and water. The right amount and source
of these may vary by the training needs. In this blog, I explore (and I deliberately use the word ‘explore’, as I am no an expert
in this space and am myself trying to find the right answers) the following two
important questions:
(i) why is each type of nutrient critical for a runner?
(ii) what are some good sources of proteins for vegetarians (something that I
struggled with before finally finding a diet that suits me)?
So,
let’s start with understanding the importance of different nutrients for a
runner.
Carbohydrates
We all know that carbohydrates are the main energy giving food.
Let us turn our attention to a slightly finer question – how much of it can we
store in the body and how much do we need during a typical running event?
When we consume carbohydrates, these are broken into glucose
and glycogen. Glucose is absorbed in the blood and circulates through the body –
this is the most readily usable form of energy. Whatever energy is not needed
immediately is stored in the form of glycogen reserves. A healthy human adult
stores around 500gms of carbohydrate – around 400gms as muscle glycogen and
around 100gms as glycogen in liver. Additionally, up to 25gms circulate through
blood vessels in the form of glucose.
Now, let’s look at the next part of the question – how much
carbohydrates do we need in a typical running event? Research indicates that in
a typical running event a runner consumes around 3gms of carbohydrates per
minute. This essentially implies that a well-nourished body has sufficient
carbs to keep the body running for around 175 minutes [= (500 + 25) / 3].
Interestingly, this is quite close to the official cut-off time of 180 minutes
for a half marathon.
If we look in terms of energy requirements, 500gms of
carbohydrates represent around 2,000 Kcal of energy, while a runner like me
(78kg) running a 21.1km stretch consumes around 1,780Kcal of energy (based on
standard running calculators).
Two important observations before we move to the next
nutrient:
The amount of glycogen that can be stored in a healthy body is limited. Any excess carbohydrates that we consume gets stored as fats – so, there is an upper limit to the amount of carb-loading that should or can be done. Any excess gets stored as unwanted fat.
Majority of glycogen (around 80%) is consumed in the muscle tissues. Hence, longer muscles are capable of storing more glycogen – next time you hear your coach say that stretching after running helps elongate and strengthen muscles, bear in mind this can potentially also increase your ability to store glycogen.
Some good sources of carbohydrates: Banana, low-fat yogurt, whole-grain
bread, pasta, green vegetables and potatoes.
Fats
Human body comprises of much more fats as compared to
carbohydrates. While the amount of carbohydrates a body can store is just around
500gms, around 10 - 20 percent of body weight (for a healthy person) can be made of fats. Research
also indicates that 1 kg fat can provide around 9,000Kcal of energy. For a
person like me (78kg), this means that my body can potentially store around 12
kg fats (or a source of 135,000Kcal energy). Now this is much more that what I
would need to complete a half-marathon or a full marathon (or even an
ultra-marathon).
However, the challenge is that unlike carbohydrates, fats
cannot be readily consumed as energy sources. Deriving energy from fats is a
relatively complex process. Fat is stored in the body in the form adipose
tissue. To derive energy from adipose tissue, it first needs to be broken
and transported to the tiring muscle. Moreover, releasing energy from the
adipose tissue requires significant amount of oxygen. Typically, while running by
the time there is a need to draw energy from adipose tissue (i.e. after depleting
glycogen store), body is already breathless and availability of oxygen to
release energy from adipose tissue becomes a limiting factor.
Another important thing to note about fats is that these are
of two types – saturated and unsaturated. Saturated fats are the ones that
usually come from animal sources and carry significant health risks (including
increased blood cholesterol level). Unsaturated fats are usually derived from
plant sources and unlike saturated fats these fats do not carry health hazards.
In fact, unsaturated fats provide some health benefits for heart.
So, what does this mean for us, the athletes? Primarily two
things:
Unlike carbohydrates, fats are available in abundance in human body and there is no need for ‘fat-loading’. This is an important point as many people end up consuming fats under the garb of ‘carb-loading’ prior to the race day.
Amount of saturated fat intake should be limited but the diet should have appropriate level of unsaturated fats.
Some good sources of unsaturated fats (good fats): Olives, almonds, walnuts,
nuts, peanut-butter, tofu, soy-milk, olive oil, soybean oil.
Water
Importance of staying well-hydrated in long-distance runs
cannot be overemphasized. During long-distance runs body loses significant
amount of water and sodium in the form of sweat. This loss of water and
electrolytes is a common reason for the occurrence of muscle cramps.
Typical dietary intakes to avoid dehydration – 2 to 3 liters
water per day and Enerzal (especially during the last few days leading to a
running event).
Vitamins and Minerals
If we draw the analogy to the automobile engine that I
started this blog with, vitamins and minerals are like lubricant oil for the
automobile. Lubricant oil is not the fuel that provides energy for motion, but it is
required to prevent wear and tear and ensure proper maintenance of the engine.
Similarly, vitamins and minerals are nutrients that are required in small
quantities for the body parts to function properly. These nutrients also help
in strengthening the body’s immune system. There are different types of vitamins and minerals, each
performing a specific function. Following table summarizes the most critical
vitamins and minerals for an athlete and some common food sources. For brevity,
I have confined the benefits to the ones most relevant for an athlete.
Proteins
Proteins are the nutrients that help in building muscle and
expediting recovery / repair of damaged tissues during high intensity work-outs
or long distance runs. Some runners tend to neglect protein, labelling it as ‘muscle-building’
food more appropriate for body builders. However, this is at best an incorrect
practice. I usually think of protein intake in two phases:
During the months leading to running events (or during off-season): This is the ideal time to work on body fundamentals and build muscle strength. For instance, it helps to develop more muscle around forearms and wrists. This helps to provide greater propulsive thrust from the swinging of arms during running. Similarly, it is critical to conduct strength training to prepare the muscles (especially leg muscles such as calves, quads, hamstrings etc.) for the stress-impact these muscles will undergo during the running season.
During the running season: If one is participating frequently in distance running events (say once in a month or two months), then the body needs quick recovery to repair the damaged tissues. Hence, here again, appropriate intake of proteins is critical.
An average human body needs around 0.8gms of protein per kg
of body weight (daily). For athletes trying to build strength or recovering
from a long-distance run, this requirement is considerably higher and is
usually in the range of 1.4 to 1.6gms per kg of body weight. For me (78kgs),
this implies a daily protein requirement of around 120gms. As a vegetarian (but consuming
eggs), I often struggled to meet this requirement. However, with experimentation I
think I have found a diet that largely serves my daily protein requirement –
sharing below for the benefit of fellow vegetarian runners:
I hope the article provides some good 'food' for thought for runners looking to improve their nutrition to enhance their running performance.
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Sundeep Singh: +91 - 98181 19794
