Nutrition will make or break your training and your race. It’s crucial to be properly trained AND fueled for maximum performance.

Whether you’re taking part in a major marathon or the local 5-K, nutrition should be part of your ongoing training, not something you start to do only in the weeks leading up to the race. Without the right nutrition, running can be negatively affected. Low energy levels and dehydration can occur when not properly fueled.

You’ll want to eat enough so you don’t feel faint or weak toward the end of your workout, unless you’re a high-mileage runner, your daily calorie needs aren’t going to be dramatically higher than a non-runner’s.

To optimize your training, when you eat as almost as important as what you eat. Within an hour of finishing your run (and ideally within 30 minutes), you should refuel with a snack.

Your post-run snack should contain all the macronutrients, carbs, protein and fat. For example: a slice of whole-grain toast with a nut butter and berries, or some fruit with Greek yogurt.

If you want to train for race, you want to incorporate healthy eating habits. This means quality foods that provide nutrients and not empty calories. This will ensure your health and performance to prepare you for a 5K, half marathon, or ultra-marathon training such as:

  • Lean meats and fish (organic and grass-fed ideally)
  • Oatmeal
  • Brown rice
  • Quinoa
  • Beans and lentils
  • Variety vegetables
  • Leafy greens
  • Fresh fruits
  • Nuts and seeds
  • Legumes

You need all three major macro-nutrients, carbohydrates, protein and fat, to perform at your best. Too little, or too much, of any may slow you down.


They provide energy for your workouts. However, when training for a 5K, you’re most likely not exceeding 20 miles per week in training. This amount of running doesn’t require a major boost in your carb intake. However, if you are training for a half marathon or more, bottom line is that carbohydrates are your body’s main and most preferred source of energy. If you’re going to be running the mileage it takes to train for a marathon, your body needs carbohydrates to fuel these miles. Period, end of story. Without them, performance will suffer, the body will be extremely stressed, and you will eventually feel fatigued and unmotivated!

Places you can get your carbs

  • Whole grain cereal
  • Plant Based Milk & Non-Dairy Yogurt
  • Whole grain Bread
  • Whole grains such as quinoa, brown rice
  • Sweet potatoes, butternut squash, winter squash, legumes


Protein is an essential component of all your tissues. It’s especially valuable in helping you build and repair muscle, which you’re doing a lot of while training. Lean proteins, such as fish, white-meat poultry and lean red-meat are ideal options.


Unsaturated fat lubricate and protect our joints and organs, aides in recovery, and helps with the absorption of nutrients. As well as keeping our body fueled and appetites satisfied. We also get the Omega 3’s which play a role in reducing inflammation, so you recover from your runs adequately. Avocado, salmon seeds, and nuts are all good sources of unsaturated fats.


You will need to hydrate during races, especially half-marathons and marathons, and in hot weather. Experiment with hydration during your training runs. Do you like drinking on the go or do you prefer to stop and take a few sips and then get back to running? Can you handle sports drinks, or do you prefer to stick to water? Use your training runs as dress rehearsals for race day.

Three to Four Days Before the Race

Emphasize carbs for energy. Increase consumption of complex carbohydrates. Carbs will give your muscles and brain the fuel they need to get through the race. Consider complex carb sources like bulgar wheat, whole wheat orzo, oatmeal, and other whole grains.

The Night Before

  • Don’t experiment. Stick with what’s familiar and what works for you the night before the race. If you had marinara sauce the night before your last successful long training run, don’t try something heavy and different on this night. A new food or spice could upset your stomach or leave you feeling “off.”
  • Eat a nutritious meal composed of whole grains (whole wheat pasta or brown rice); grilled or steamed vegetables or a salad (lettuce, tomatoes, carrots, and light dressing); and a protein source such as tofu, beans, or tempeh. Again, stick with what’s familiar.
  • Continue with hydration, drink water.

My Top tips

1. Eat protein and fat-NOT just carbs! Carbo-loading is the universal strategy used by endurance athletes for prolonged energy during their runs. Runners can certainly benefit from consuming an adequate amount of carbohydrates, but it’s also important to also eat protein and fat. Although carbohydrates are burned for energy, protein and fat are the two macronutrients that have more power to hold you over. Strive to maintain a balance of protein, fat and complex carbohydrates at your pre and post run meals. It’s okay to load up on carbs, just make sure you load up on fat and protein too!

2. Eliminate artificial sweeteners and sugar alcohols. Ever experienced gastrointestinal issues while running? Artificial sweeteners and sugar alcohols can cause extreme irritation to the gut, even hours after consuming them because the body has trouble processing them. They are found in many popular running fuels. Also, if you are experiencing constant GI issues during your runs you may greatly benefit from taking daily probiotic (or eating your probiotics) supplements to support gut integrity. This strategy has worked miracles for many of my clients who are runners.

3. Eat those fats—healthy fats that is! Fats lubricate and protect our joints and organs, to aide in recovery, help our body with temperature control and the absorption of nutrients, and to keep our body fueled and appetites satisfied. Low-fat diets for runners are VERY damaging. Do not deprive your body of a macronutrient that it so essential. Make sure to include nuts, seeds, and avocado in your daily intake. You won’t regret it.

4. Bottoms up on the vitamins. Runners have high demands for nutrient needs. Runner can benefit from supplements to support joints and cartilage, to aide in injury prevention, and for optimal performance.

5. Pre-run Fueling: Some runners can munch on food until the second they hit the pavement, but others need to let their food digest and stomachs settle first. How much you should eat before a run depends on your distance, your personal tolerance and the timing of your run. For me, either a short run or “Long Run Saturday” -I run on an empty stomach. Some people have a banana or a bagel with a nut butter. Some people can’t handle having a lot of fat before they run, because fat takes longer to digest. Again, the key is to know yourself and experiment with what your body can handle during your training.

6. Post-run Fueling: I would suggest waiting about 30 minutes before you eat to let your body get into a more relaxed state so it can digest your refuel food. I recommend a balanced meal consisting of protein to aid in muscle recovery, healthy fat to support your joints and carbohydrates to replenish the ones you burned for energy. This meal doesn’t need to be anything special; it just needs to contain all three macro-nutrients. For example: a balanced meal would include eggs and spinach cooked in olive oil with quinoa or whole grain bread or fish served with a sweet potato and cooked veggies.

What are some your nutrition tips for runner? What works best for you?
Please comment below or comment on instagram @nutrition_connections

Carol Aguirre MS, RD/LDN