Senior Distance Running Essentials Series

Chapter 8: Nutrition (May 2024 Update)

In this episode we are looking at one of my favorite topics – nutrition. In my mid-20s I studied food science and human nutrition in graduate school.  I eventually changed majors but what I learned about the composition of foods and the vital link between nutrition and health has stuck with me. 

What to believe?; What to do?

There is so much information out there about nutrition that it’s really hard to determine what to believe, what to do.  In part, that’s because nutrition is such a big field, is so vital to our daily function as well as athletic endeavors, and by its very nature has specific individual application.  

There are some excellent resources available, including Nancy Clark’s Sports Nutrition Guidebook, which I highly recommend.  We will focus here on the big picture aspects of nutrition most affecting senior runners.

Clearly, there are differences in food tolerances as well as philosophical and religious choices that limits one’s diet. This presentation is more general and does not attempt to address those situations.  

So, to begin, let’s consider the key metabolic challenge our body seeks to manage:  we need energy and other nutrients throughout our bodies continuously or at varying rates but only ingest food periodically.  This requires fine-tuned, intricate mechanisms that allow for the absorption, storage, retrieval, and delivery of energy and nutrients.  Aging tends to slow or otherwise impact these mechanisms.

Energy requirements

We runners tend to focus on our energy needs.  We know we can’t perform well (or at all!) if the energy well runs dry.  There are several metabolic pathways that deliver energy.  Some tissues in our body are more picky than others.  For example, the brain and the rest of the nervous system can only use simple sugars for energy, with glucose being the primary one.  Our muscles, however, can use not only glucose but also lipids (commonly called fats) for energy.  In fact, this is one of the key objectives of endurance training: to get the body more used to accessing energy directly from stored lipids. This is critical in longer races as we use up the glycogen (which gets metabolized to glucose) stored in our muscles and liver.  

Also, energy delivery in the body is not like a hybrid electric vehicle transitioning from stored electricity to gas.  Depending on the intensity of exercise, there is a continuum where energy is drawn simultaneously from both lipids and glucose.  Suffice it to say, this is complicated stuff!

Nutrition, as it relates to athletic performance, boils down to three questions: (1) What to eat; (2) When to eat?  (3) How much to eat?  We are asking our bodies to deliver top performance.  And to do that we need high-grade fuel, in the right amount, at the right time.  In addition, the answers to these questions vary by individual.  

What to Eat?

Macronutrients

You likely know food is composed of three caloric elements, or macronutrients: carbohydrates, fat, and protein.  (Yes, alcohol also has calories but is outside of our consideration here.)  

Micronutrients

In addition to these three macronutrients, there are a host of vitamins and minerals, sometimes called micronutrients, needed by our bodies. We’ll cover those briefly.  And we’ll also check in on hydration.

An age-old question: optimal caloric split?

The ideal caloric split between macronutrients varies. Endurance athletes typically do well with diets comprised of 50-60% carbohydrate, 20-30% fat, and 15-25% protein. Few senior runners are still doing mega-miles.  High mileage commands an even a greater proportion of carbs.

Protein

Protein is a key structural component of most tissues in our body.  Bone is about 50% protein and muscle 20%.  Hemoglobin, which transports oxygen to our tissues though our blood, is composed chiefly of protein.  Athletes of all stripes experience an increased breakdown and repair of bodily tissues and thus need more protein.  Protein also plays a role in energy production and our immune functions.  Sufficed to say, protein is a crucial part of our diet.

How much protein do endurance senior runners need?  The argument for more draws from studies showing seniors are less able to absorb the amino acids that make up the proteins in our muscles and bones.  On the side of less, seniors tend to have less muscle (though strength training can help us there!) and we are likely not training at the volume and intensity of our younger selves. Overall, we should probably target to have 20-25% of our calories come from protein, thought there can be a tendency to go overboard on this.  

Effect of high protein diets

There is some evidence very high protein diets may have negative effects on the kidneys.  But most studies have focused on kidney-impaired subjects.  For healthy athletes, it’s more about the type of fat ingested along with animal protein that is of concern.  As with all things nutrition, balance is a guiding principle.  Our protein needs can generally be met by a standard diet with foods such as skim milk (40% protein), nonfat cottage cheese (60% protein), and the occasional boneless chicken breast (75% protein!).  Fish is mostly water but is 12-20% protein depending on the kind of fish.

What are essential amino acids?

Our bodies require 20 amino acids to build the array of proteins needed in our bodies. Eleven of these are produced naturally by our bodies, leaving nine as essential – meaning they must come from foods we eat or supplements ingested. Here’s the list: 

• Histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine

You may have heard of some of these but it’s not that important to know them.  What is important is these essential proteins come from a variety of foods and we’ll discuss that in a moment.  But here’s a catch to be aware of – it’s called the all-or-none rule.  While not all proteins require all 20 amino acids to be built, each protein does have very specific requirements.  For example, if a protein in our leg muscles needs seven of those nine essential amino acids and through our diet we only get six of them, we’re simply out of luck.  That particular protein cannot be built!  

So how do we ensure we have a pool of the needed proteins?  One way is to eat some animal protein, such as milk products, fish, or meat.  Protein from animal sources generally contains all nine of the essential amino acids and are thus called “complete” proteins.  On the other hand, most proteins from plants are typically “incomplete,” with soy products and quinoa important exceptions.  However, with many runners increasingly eating vegetarian diets, it’s important to note that protein from a mixture of nuts, soy, legumes, and whole gains can easily meet our protein needs by combining plant-based foods that together contain all nine of these amino acids. There are plenty of resources out there to help determine this.  

The main takeaway on protein is to not skimp on it.  As to the when question, it’s best to include some protein in every meal. Spreading out protein consumption will help ensure having enough to rebuild tissues broken down from intense training. 

Fat/Lipids

Next, let’s look at fat.  In the nutritional world, these are called lipids.  Fats are actually a type of lipid but include most of what we ingest.  So, for this presentation we’ll refer to the fat content of foods.  

Fat is the bugaboo of the modern diet.  But the concern is warranted. Many eat a diet too high in fat, leading to weight gain and cardiovascular issues.  One reason for this weight gain is the caloric value of fat is more than twice that of protein and carbohydrates. Protein – 4 cal/gm; CHO – 4 cal/gm; Fat – 9 cal/gm. The other reason is food high in fat, often salted, tastes so good it’s hard to resist!  A basic amount of fat is needed, but there is no prescribed floor.  This is why diets very low in fat, say only 10% of calories, can be fine.  

There are just two essential fatty acids: Omega-3 and Omega 6. These must come from the diet.  But those needs are fairly easily met with vegetable oils used in food preparation, and if you are not vegetarian, in fish.  The real problem with a fat-restricted diet is it tends to leave us more hungry as digestion of fats is typically slower than protein or carbohydrates, often leaving us feeling fuller, for longer.

Of the various types of fat, saturated fats have the bad rap.  And they’ve earned it!  These are the ones that tend to clog our arteries and generally gum things up.  They come largely from animal sources.  Thus, a reason to minimize, or eliminate, certain types of meat from the diet.  Unsaturated fats, which are less likely to accumulate in blood vessels, are found in seeds, nuts, olive and vegetable oils.  

Our liver is super important! 

The liver does a lot of things, but we may tend to take it for granted unless it malfunctions.  It plays a vital role in fat metabolism and our overall blood chemistry.  It produces most of the cholesterol we need, regardless of how much cholesterol is in our diet. We may think of cholesterol as bad, and in excess it is, but it is a necessary component of cell membranes and some hormones, such as testosterone.  The liver also breaks down the nutrients and chemicals found in foods and changes these into forms that are easier for our bodies to use.

How much fat?

So, how much fat should we have in our diet?  If the typical American diet is 35-40%, I’d say half of that is sufficient.  Rounding up, that’s 20%.  In part this leaves room for increased protein and adequate carbs to fuel our running.  We’ll look at labeling shortly.  But if your choice is to move to a lower fat diet, it will take effort and perhaps some retraining of your eating habits.  Endurance training does result in being better able to use fats for energy, so very low-fat diets can actually work against performance for some runners.

Carbs

Last are carbohydrates, which come mostly from plants.  Unlike protein and fats, none are essential.  They are categorized according to their level of complexity, which affects the steps needed to break them down to glucose, the fuel used by our cells to produce energy.  

While we could potentially live without carbohydrates for an extended time, many of the vitamins and minerals we need come from carbohydrate-rich foods.  And if carbohydrate, which is stored in the body as glycogen, is not available, our body must break down fats, and in extreme cases protein to generate energy.  As noted in the beginning of this chapter, if our brain or heart cells do not have a constant supply of energy, we’re toast!  

The dreaded “Wall!”

Probably most of us have experienced the feeling of “hitting the wall,” when we temporarily run very low on energy.  Not a good feeling!  And if we’ve miscalculated on our fueling, no amount of will power will allow us to perform at our best.   

One piece of good news is that as we age, our ability to absorb and utilize carbohydrate stays pretty level. That said, whatever our age, timing is critical in carbohydrate consumption, and we’ll look at that next.

When to Eat?

We really run into individual differences when looking at this second question.  For nonathletes, this is less important, though the sequencing of absorption, storage, and release of energy applies to everyone.  For athletes, it is somewhat sport specific.  Coaches suggest we distance runners plan to eat carbohydrates in advance of and during a long training run or event and then refuel shortly thereafter, along with some protein to help build back lost muscle fibers.  Yet, it’s not as simple as loading up on carbs shortly before a race and expecting that to carry us.  Doing this could have the opposite effect, leading to an energy crash due to an overload of glucose in our blood.  There is a lot of science and a whole industry revolving around fueling.

Experiment!

The key is to find out what works for you.  This is part of training!  Know how well you digest certain types of food before going on a run or racing.  For example, I always drink a large, strong cup of coffee before running to help clear my system out.  I used to put milk in my coffee and often had side stitches when racing.  And when you get one of those, it’s tough sledding!  But after taking out the milk some years ago, the stiches went away and have not returned.  And I find I like the taste of black coffee better anyhow! 

Time to digest

Certain foods stay in our stomach longer.  Protein-rich foods are slower to digest, and the same with fat, which is good if you’re looking to stave off hunger.  But if you want to avoid the sloshing of food while running, it’s probably best to look at more digestible carbohydrates for pre-run meals.

We runners are most concerned with having enough energy to fuel our muscles to keep going at a solid pace. You don’t want to bonk at mile 11 of a half marathon having passed on Gatorade at the mile 5 and mile 8 aid stations.  This is another thing to figure out during training, not on race day! 

Digestion takes longer as we age

While there are some general guidelines about when to eat, take the time to figure out what works for you and what doesn’t.   Recall that most digestive processes take a little longer as we age.  

Foods to Avoid

Are there foods we should avoid or at least minimize?  From a health perspective, saturated fats stand out.  Nothing about saturated fat is good.  Most of us probably grew up eating French fries cooked in lard — McDonald’s used lard until 1990.  The good news is fried foods are now mostly cooked in unsaturated fats.  Low-grade ground beef, sausage, bacon, butter, premium ice cream, and coconut oil are all high in saturated fat.  We make important choices each day.  But as with all things, reason should prevail.  A small piece of birthday cake is not going to set us back.

How Much to Eat?

This third question has two parts: how much of particular foods to eat and how much to eat in total calories?  We’ve covered some of the first question already.  Thus, we will focus now on the second question.

Energy Balance = Calories Eaten – Calories Burned

Ultimately, it comes down to what is called energy balance, which is a comparison of calories eaten vs. calories burned through activity.  If, over time, the amount we eat equals the amount we expend, our weight is unchanged. 

For an endurance athlete, things are a bit more complicated, as our workout regimen will vary by day. However, over the course of a week, or a month, this dictum tends to hold.  For example, an average size, reasonably active male needs about 2,500 calories a day to maintain weight and a female about 2,000 calories.  That male would expend about 17,500 calories a week.  If he runs 40 miles a week, that would likely add roughly 4,000 calories to that total, so 21,500.  We’ll look at food labeling shortly, but in general it’s good to have a sense of the calories we take in and whether that approximates our expenditure — the scale will tell us if we’re off!.  Energy balance plays no favorites – it doesn’t care whether these calories come from protein, fats, carbohydrates or alcohol.

Energy needs are composed of three components: basal metabolic rate (or BMR); the energy cost of digesting foods, and for physical exertion. BMR is directly related to the amount of muscle we have.  Even if we strength-train, we’re likely to see muscle loss in our 50s and beyond.   Thus, when looking at a male’s baseline energy needs, a 65-year old might be closer to 2,250 than the 2,500 noted above.  Again, the scale is our aide here.  

Gaining and losing weight

It gets more complicated when we are aiming to gain or lose weight.  Gaining might be an objective for a super-lean competitive senior runner wishing to add muscle.  It takes a surplus of roughly 2,500 calories along with strength work to build a pound of muscle.  To lose a pound of fat, the deficit will need to be about 3,500 calories per pound.  It gets really tricky and less formulaic if we are trying to lose weight while building muscle!  A registered dietitian can help with this.            

The goal is healthy weight

Distance runners have always cared about weight.  We intuitively know if we’re lugging extra weight, it costs us.  But we have to be really careful here – I am talking about healthy weight.  The prevalence of eating disorders among runners is well known.  It may be hard to ask for help with this, but those who have gone through such issues would underscore the importance of professional guidance. 

With this caveat, studies show that each pound above our healthy weight costs all-aged runners roughly two seconds per mile.  So, for a half marathon, 10 pounds of “extra” weight can cost us about 4 minutes.  I suggest the difference between a 1:48 and 1:44 half marathon time is significant for a results-driven runner.

Optimal weight

Intuitively, we know our optimal weight.  The mirror and a pinch test tell us if we are carrying a few extra pounds.  If our ribs are protruding and we are chronically tired, that tells us something else.  On the scale, our optimal weight will likely be less than it was in our 30s, and 40s.  Like it or not, we’ve lost some muscle and bone even if we’re consistently doing strength work.  As we noted in the episode on muscle, invisible fat (to the eye at least) infiltrates our muscles with age and fat weighs less than muscle and bone.

BMI – a good measure?

Our optimal weight depends on various factors.  A standard measure used, body mass index, or BMI, has limitations.  It’s a measure of weight over height, [BMI = weight (lb) / Height (in)² x 703] and can be misleading.  Those with a good amount of muscle or larger bone structure will have a higher BMI even if you can’t find an ounce of fat around their midsection.  Runners are often thin and lean, with slender waists, narrow hips and shoulders, small joints, and longer legs. Think of the Kenyan’s you’ve seen running!  This tends to reduce BMI.  One study of marathoners and half marathoners indicated an average BMI of 20.7, which is 78% of the U.S. average of 26.5.   There is no prescribed ideal BMI.  It is merely one indicator that might be useful.  

Food labeling

So, back to energy balance.  How can we know how many calories we are eating? FDA-prescribed food labeling helps us.  Here’s a typical label:

These labels tell us the calories per serving, how much is in that package, the amount and type of fat, total protein and carbohydrates.  I am honestly a bit obsessive with labels.  I look at the label of everything I buy before putting it in the cart.  Maybe a carryover from my nutrition schooling.  How is this useful?  

Let’s look at the label of my preferred brand of vanilla ice cream – Elan lowfat frozen yogurt on the left vs. Ben & Jerry’s premium vanilla.  Notice the calories in Ben & Jerry’s are roughly twice that of Elan.  And the fat in Elan is one-sixth of Ben & Jerry’s.  Yet, I find the taste just as good!

Labels are a tool

You might be surprised at the caloric differences among various crackers, muffins, and dairy products you buy.  So, food labels are a tool.  Put them to use.  You will find, if you have not already, this to be an educational exercise.  Why wouldn’t we want to have a good sense of what we’re putting into our bodies?

Micronutrients

Now we’ll consider the senior runner’s need for vitamins and minerals.  

Vitamins

Vitamins are designated by capital letters: The best known are A. B, C, D, E, and K.  They were initially named by their order of discovery.  (In case you’re wondering, the vitamins between E and K were subsequently reclassified.)  Vitamins provide no calories but are essential co-enzymes, which speed up various chemical reactions in the body, including the production of energy.  

Vitamins are essential in two ways: One, they function as catalysts — the reactions they speed up simply won’t happen quickly enough without their presence; two, with the partial exception of Vitamin D, they are not produced by the body and thus must be provided in the diet, often in carbohydrate-rich foods.  

Most vitamins are fat-soluble, meaning they bind to and are absorbed with dietary fats and can be deposited in fat tissue.  This means they can accumulate in the body, resulting in vitamin toxicities that may have potential negative health consequences.  As with all things, moderation is important!  

The exception is Vitamin C.  As a water-soluble vitamin, it does not accumulate and is essentially flushed out through the urine.  Thus, high doses of Vitamin C literally go down the drain!

Minerals

Minerals, likewise, must come from our diet.  While they also provide no calories, we would be lost without them.  They become part of our body and comprise about 4% of our weight.  

Calcium is especially important.  Not only is it the foundation of our bones and teeth but it’s an essential component in energy production, as was noted in Chapter 4 where we looked at the sliding filament theory.  Phosphorous, and magnesium combine with calcium for strong bones, tendons, and ligaments.  Iron is a vital oxygen-carrying component of our blood’s hemoglobin. Sodium and chlorine combine to form sodium chloride, a shortage of which can lead to muscle cramps. 

A number of so-called trace minerals such as zinc, copper, manganese, and iodine are needed in very small amounts but if they are missing can lead to impaired immunity and decreased bone growth, among other things. 

Are we getting enough?

Nutritionists emphasize a balanced diet drawn from the basic food groups will generally provide our needed vitamins and minerals.  Are the needs of athletes, and senior runners in particular, greater than the diet provides?  The reality is the absorption rates of many vitamins and minerals decline with age.  To be safe, many, and I am among them, take a daily regimen of vitamins and mineral supplements — in moderation of course!  

Again, if you have any question about the adequacy of your diet meeting your needs as a senior runner, seeing an experienced registered dietitian, who ideally runs, is worth the time and cost. 

Hydration

Hydration is our last topic in this chapter.  The average adult male is about 60% water; a female 55%.  Most of the water in our body is within cells.  Muscle cells, have a particular affinity for water and are about 75% water.  With roughly half our weight due to muscle, this tells us much of the water in our bodies is found in muscle.  And, as we’ve noted, with age we lose muscle. Though we can (and should!) mitigate that to some degree with strength training.  As a result, men over 65 are about 55% water, instead of 60% in younger years.  There is a similar loss in women.

So, does that mean with age we need less hydration?  The short answer is no!  And this is particularly true for senior endurance athletes.  We need water to regulate body temperature when exercising and since our internal cooling system becomes less efficient with age, we need to keep hydrating.  Couple that with a diminished thirst mechanism that signals our need for fluids and we may be chronically underhydrated.

In addition to water, hydration comes from tea, coffee, juices, soda, milk, and sport drinks.  And the water in food counts too.  Cold watermelon on a hot day is hard to beat!  We’ve all seen people tethered to their water bottles. But let’s keep this in perspective.  Unless we’re in a longer race, some pre-hydration and post-run hydration should be sufficient under most conditions.  Naturally, “most conditions” do not include running on a sunny, 90-degree day.

So, I close this episode knowing I have, at best, hit some highlights.  Some say, “all things in moderation.”  And that certainly applies to nutrition. However, our standards are high – we are aiming to maintain a credible, if not an exceptional, level of performance as we age.  This requires us to take a close look at what we eat.  

It is nothing short of amazing of how food is transformed in our bodies.  And we want to give that food the best chance of keeping us healthy while giving us the oomph to crest those hills and keep a steady pace!

This concludes Part 1, which serves as background for the next six applied chapters.  

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Meanwhile, keep running.  It’s still as simple as one step followed by another!