By RunDoyen.
Featuring coaching insights from Will Benitez.
RunDoyen connects runners with expert online running coaches and race-focused training plans built around real goals, real schedules, and long-term progress.
TL;DR
- Running nutrition needs change with age, workout intensity, training volume, and race distance.
- Fasted running may fit some shorter, easier sessions, but harder workouts generally call for pre-run fuel.
- Marathon preparation usually requires more total energy, carbohydrates, protein, hydration, and attention to fueling during runs.
- As runners age, protein, bone-supporting nutrients, and greater food variety become increasingly important considerations.
- Dizziness while running should not simply be pushed through. Hydration and low blood sugar are possible contributors, but persistent symptoms deserve further evaluation.
If you want your training, recovery, and fueling habits considered together, RunDoyen can match you with an online running coach around your goals and schedule.
Table of Contents
- Why running nutrition needs are not fixed
- How nutrition needs can change with age
- Fasted versus fueled running
- Why marathon training changes the equation
- A five-step fueling decision framework
- Common running nutrition mistakes
- Safety and when to get help
- Putting your fueling decisions into practice
Why Running Nutrition Needs Are Not Fixed
There is no single fueling approach that fits every run.
A short, comfortable outing places different demands on the body than a hard workout. Training for a 5K is different from preparing for a marathon. A runner in their 60s may also need to pay attention to different nutritional priorities than they did decades earlier.
That means the better question is not simply, “What should runners eat?”
It is, “What does this runner need for this training demand?”
That distinction matters because runners are often creatures of habit. When a meal, snack, or routine works without upsetting the stomach, it is easy to repeat it indefinitely. Consistency can be useful, but nutritional needs can still change as training and life change.
The goal is not to reinvent your diet every week. It is to recognize when your current routine no longer matches what your training requires.
For a broader foundation on hydration, fueling, and recovery, RunDoyen’s guide to nutrition for runners provides useful context.
How Nutrition Needs Can Change With Age
Two areas deserve particular attention as runners get older: protein and nutrients that support bone health.
Protein needs can rise meaningfully with age. As one example, a runner consuming roughly 75 grams of protein per day might eventually need something closer to 115 grams, approximately a 50% increase, depending on age and individual circumstances.
That example is not a universal prescription. It illustrates the size of the adjustment that may sometimes be necessary.
Bone-health nutrition also becomes increasingly important. Nutrients highlighted for consideration include:
- Calcium
- Vitamin D
- Vitamin K
- Magnesium
- Potentially zinc
These can come from a combination of whole foods and fortified foods. Milk and fortified non-dairy alternatives, soy foods, legumes, beans, and dark greens are among the examples discussed.
Variety matters, too.
Runners often repeat the same foods because those foods feel predictable before and after training. But maintaining a broader food rotation can become particularly useful as nutritional priorities change with age.
The practical lesson is simple: a fueling routine that worked well years ago should not automatically be treated as permanent.
Fasted Versus Fueled Running: Start With the Workout
Running on an empty stomach is not automatically good or bad. The usefulness of fasted running depends heavily on the session.
One obvious advantage is comfort. Many runners dislike the feeling of running while full or actively digesting a meal. An empty stomach can create the lighter feeling some runners prefer.
There can also be a training rationale for occasional lower-intensity fasted running, including greater fat oxidation and less reliance on carbohydrate during the session.
The tradeoff appears when intensity rises.
Easy Zone 1 or Zone 2 running may be more compatible with a fasted approach for a runner who tolerates it well. Once the session moves toward Zone 3, pace work, or a demanding workout, inadequate fueling can contribute to earlier fatigue and make it harder to sustain the intended intensity.
Your schedule matters as well.
Consider a runner who plans to train at 5 p.m. but has eaten very little since noon because they wanted to avoid feeling full. That runner may arrive at the session with inadequate fuel available. The desire to protect stomach comfort has now created another problem.
A hard workout is generally not the time to experiment with how little fuel you can tolerate.
The same logic applies if you know you will not be able to eat promptly afterward. Going into the session fueled can make more sense than extending an already long period without food.
Runners with existing hormonal concerns should also be cautious about making frequent fasted exercise a default habit and can discuss individual considerations with an appropriate healthcare or nutrition professional.
Why Marathon Training Changes the Equation
As running distance and training volume increase, fueling requirements usually rise with them.
Marathon preparation tends to require more of several things:
- More total energy
- More carbohydrates
- More protein
- More hydration
- More deliberate fueling during longer runs
Carbohydrates may make the largest proportional jump.
For example, imagine a runner who has been training for 5Ks or 10Ks and consuming roughly 50% of total calories from carbohydrates. As marathon preparation begins, that proportion might increase toward approximately 55% to 65%.
The correct number depends on the runner, the training structure, and overall needs. The important point is the direction of change: marathon training substantially increases the demand for carbohydrate availability and glycogen replenishment.
That does not mean protein or fat becomes unimportant. More training also means more recovery demand, so protein remains relevant, while dietary fat remains part of the overall nutrition picture.
Hydration changes as well. Longer runs and potentially more frequent training create more opportunities to lose fluid. Electrolytes may become a more regular part of the routine.
A runner who rarely used sports nutrition during 5K preparation may also begin experimenting with gels, chews, or liquid calories during marathon training.
Those products are not mandatory. Whole-food approaches can work in some situations. But the marathon distance makes practicing an actual fueling strategy increasingly important.
RunDoyen’s training plans cover different race distances, while the marathon training guide provides broader context for the demands of preparing for 26.2 miles.
A Five-Step Running Fueling Decision Framework
Rather than using the same rule every day, work through these five questions before deciding how to fuel a run.
- Identify the session demand.
Is this a short easy run, a long run, or a higher-intensity workout? The harder and longer the session, the stronger the case for deliberate fueling. - Consider how long it has been since you ate.
An easy morning run after a normal evening of eating is different from an evening workout after five hours with little food. - Choose fasted or fueled based on the purpose of the run.
An easy Zone 1 or Zone 2 session may be compatible with fasted running for some runners. Pace work and harder efforts generally call for more fuel availability. - Plan hydration and portable fuel when the run demands it.
Longer training may justify water, electrolytes, gels, chews, dried fruit, liquid calories, or another tolerated option. - Review how you actually felt.
Energy, dizziness, unusual fatigue, stomach comfort, and your ability to complete the planned intensity all provide useful feedback. Adjust the next session rather than assuming one routine must work forever.
This framework is intentionally simple. It helps connect fueling to the actual purpose and timing of the run.
Common Running Nutrition Mistakes
- Using the same nutrition routine year after year. Aging and changing training demands can alter what your body needs.
- Avoiding food for too long before an evening run. Fear of feeling full can turn into inadequate pre-run energy.
- Using fasted running for every type of workout. A strategy that feels fine on an easy run may undermine a harder session.
- Failing to increase carbohydrates as marathon volume rises. Longer training places greater demand on glycogen stores.
- Waiting until race day to try gels or chews. Marathon training gives runners an opportunity to practice the products and routines they may use while racing.
- Ignoring hydration until thirst becomes obvious. Marathon preparation can substantially increase overall hydration demands.
- Treating dizziness as something to push through. Dizziness can be a signal that the run needs to be slowed or stopped.
- Eating too narrow a range of foods. Familiarity is useful, but greater variety can help address changing nutrient priorities.
Safety and When to Get Help
Dizziness during a run deserves attention.
Possible contributors discussed here include dehydration, low blood sugar, heat, inadequate sleep, and an effort that is simply too hard for the circumstances. Medication and underlying health conditions can also be factors.
In the moment, slowing down is reasonable. That may mean jogging easily, walking, or ending the workout rather than trying to force the planned session.
Afterward, consider the circumstances. Had you eaten adequately? Had you been drinking fluids? Was the weather particularly hot or humid? Was your sleep poor? Were you running unusually hard?
If dizziness is recurring, significant, unexplained, or continues despite addressing basic fueling and hydration factors, talk with a healthcare provider. Do not rely on nutrition changes alone to explain persistent symptoms.
This article is educational and is not a diagnosis or individualized medical treatment plan.
Putting Your Fueling Decisions Into Practice
Good running nutrition is less about finding one perfect rule and more about matching your choices to the runner you are today and the training you are doing today.
An easy run and a hard workout do not require identical preparation. A 5K build and a marathon build do not create identical fueling demands. Nutrition priorities can also evolve as runners age.
Pay attention to those changing demands, practice what works during training, and adjust when your energy, recovery, or symptoms suggest the routine is no longer serving you.
If you want individualized training decisions that account for your schedule, workout demands, and long-term goals, you can browse RunDoyen’s running coaches and learn more about their coaching approaches.
FAQ
Should runners eat before every run?
Not necessarily. Some runners may tolerate shorter, easier runs without eating immediately beforehand. Harder workouts, higher-intensity running, long gaps since the last meal, and longer sessions create a stronger reason to fuel before running.
Is running on an empty stomach good for you?
It can have advantages and disadvantages. Some runners enjoy the lighter feeling, and lower-intensity fasted running may increase reliance on fat as fuel. The tradeoff is that harder sessions can become more difficult to sustain without adequate carbohydrate availability.
Should I fast before a speed workout?
The source guidance favors fueling before workouts and higher-intensity sessions. Once running moves beyond easy Zone 1 or Zone 2 effort, lack of fuel can contribute to earlier fatigue and difficulty holding the planned intensity.
How does marathon nutrition differ from 5K or 10K nutrition?
Marathon training typically raises total energy, carbohydrate, protein, hydration, and during-run fueling needs. A runner may also begin using electrolytes, gels, chews, or other sports-fueling products more regularly as long runs increase.
Do runners need more protein as they get older?
Protein can become a greater nutritional priority with age. The source gives an example in which an older runner’s intake might rise from approximately 75 grams to around 115 grams per day. Individual requirements vary, so that example should not be treated as a universal target.
Why might I feel dizzy while running?
Possible contributors include dehydration, low blood sugar, heat, poor sleep, and excessive effort. Medications and health conditions can also play a role. Recurring or unexplained dizziness should be discussed with a healthcare provider.
How can an online running coach help with fueling decisions?
An online running coach can help align workout timing, intensity, long runs, and recovery with the runner’s real schedule. When nutrition questions require more individualized expertise, those training decisions can also be coordinated with an appropriate nutrition professional.
