Lots of people think that if you run or work out a lot, you can eat anything you want, because you’ll burn it off. Well, that’s not quite accurate, although you will need to eat more if you’re training heavily. But as you continue to train, you’re going to find that at certain times your workouts go really well, and at others you’re dragging yourself through them. The difference is usually linked to one of three reasons: 1) How much sleep you’re getting, 2) how well your body has recovered or 3) how well you’ve been eating and drinking (both quality and quantity).

Get enough sleep. The longer your workouts, the more rest you need. Everyone has a somewhat different threshold on how much sleep they need, but everyone needs more of it when doing long workouts.

Body recovery is directly linked to proper nutrition. For about 2 hours following a hard workout, your body assimilates carbohydrates at a 50% increased rate. So, if you eat some carbohydrate after your workout, a higher percentage is going to be used to re-fuel the muscles.

Some basics: The “combustion chambers” of your muscle cells (mitochondria) use different types of fuel depending upon how hard you’re working. Fast, explosive bursts of energy, such as weight lifting causes the body to use mostly Creatine Phosphate and Adenosine Triphosphate (ATP) for fuel. But this fuel supply is extremely limited and lasts only seconds. For longer-term exercise, the body’s preferred fuel source is fat (with some carbohydrate). But Fat requires more oxygen to burn than carbohydrate. As you exercise at higher levels of intensity, you feel yourself breathing more heavily as the body tries to get enough oxygen to the muscle fiber to burn fat. When that doesn’t work, it increases the percentage of carbohydrate it’s burning. Carbohydrate doesn’t need as much oxygen. At higher intensities, your body burns a rich mixture of carbohydrate as its fuel source.

The problem here is this: First, your total supply of carbohydrate stored in your body (as either glucose or glycogen) is limited to about 2,000 calories, or enough to run 18-20 miles. The total supply of fat in the body is about 80,000 to 100,000 calories in the average person or enough to go a long, long way.

So, the preferred fuel source is fat. But, you have plenty of fat stored in your system already, and the body has an unlimited ability to store more fat, unlike carbohydrate, which is limited to around 2000 calories. You don’t need to ingest more fat given the level of stores. And fat can not burn as fuel on its own, but needs oxygen and carbohydrate. Whether your primary fuel source is fat or carbohydrate, some of our precious carbohydrate is needed to fuel the fire. Ergo, the need to consume carbohydrate to maintain (or replenish) the limited supplies.

We train in the early season to increase the body’s ability to burn fat efficiently. Those long slow runs at a heart rate approximating 65-75% of maximum train the body to use the fat burning fuel system more efficiently.

A short note about protein: Protein is not a primary fuel source, but is used to build and repair muscle and other body tissue. Because of this, protein is also important to your nutrition plan. Training for an endurance event is a process of constantly breaking down muscle fiber and allowing it recovery time to re-build itself to a stronger state. It requires protein to do this. Although most of us get sufficient protein, athletes do require more protein than the average person. The rule of thumb is that an average person should ingest about 1 gram of protein for every kilogram of body weight. An endurance athlete requires 1.5 to 2.0 grams per kilogram of body weight (1 kilogram [Kg] = 2.2 pounds). To calculate how this breaks down for you, follow this example:

  • For someone who weighs 160 pounds, their weight in kilograms is 160 ÷ 2.2, or 72.7 Kg.
  • 72.7 Kg x 1.5 = 109 grams.
  • Since each gram of protein contains approximately 5.65 calories, 109 x 5.65 = 615.8 calories.
  • This person’s protein level should be about 616 calories per day.

Well, how and what should you eat to insure adequate fuel? Here are some suggestions:

  1. Never run without proper fueling first. Eat something preferably an hour or so before your run. Stick with foods primarily low on the glycemic index. Eating sugary foods (including ripened bananas, donuts, bagels and bread comprised of mostly enriched white flour) will spike your blood sugar causing and “insulin response” and a quick reversal of the sugar high to an energy-low-tired feeling.
  2. If eating an hour before your run isn’t practical (say, if you’re doing your run early in the morning), use a liquid form of nutrition. There are several of these on the market and can be purchased from sports and nutrition stores. Liquid meals, low fat yogurt with fruit and granola and a banana are good choices for most people.
  3. Get something to eat just after your workout. No binges, just a piece of fruit or a bagel immediately after. A few minutes later, some additional “quality” carbohydrate. A while later something else. Small quantities over a one to two hour period assures that the carbohydrate will be assimilated to your system to replenish depleted glycogen stores. Some protein should also be included in your post-workout eating, since protein is used for recovery and rebuilding.
  4. Eat enough. You don’t want to over-do it, but you’re burning more calories when you are training. There are a variety of ways to calculate your base caloric need over 24 hours, but for simplicity, multiply your weight in pounds by 15. If we use the example of the athlete weighing 160 pounds:
    • 160 x 15 = 2400.
  • Now add the value of your daily workouts. Running generally burns (on average) 100 calories per mile. If you are running 6 miles per day, add that onto your base number (so, 6 x 100 = 600, 2400 + 600 = 3000).

Make sure you are eating enough to replace what you burn. (You can also calculate your energy needs very accurately using the Nutrition Analysis Tool available on the internet from the University of Illinois. Go to: www.uiuc.edu/

  1. Eat quality. Fried is bad! Sugar (high glycemic foods) is bad! Focus on fruit, salad and colorful vegetables. When eating sandwiches, make them with 100% whole wheat bread (it tastes better anyway), and go really easy on the Mayo. Your nutrition breakdown should approximate: 60% carbohydrate (fruits, veggies, breads, pastas, etc.), 15-20% protein (from animal sources: dairy, meat, poultry, fish; from soy products; and from kidney beans, lentils, peanut butter, and almonds) and 20-25% from fat (good fats preferably: from vegetable sources- corn oils, olive oils, cannola, peanut butter and also from cold water fish). Bad fats primarily are from animal sources: meat, whole milk, and dairy products. Continuing the above example, if our diet should be 3000 calories per day:
  • 3000 calories x 60% = 1800 calories from carbohydrate/ 4.2Kcal = 428gms.
  • 3000 calories x 20% = 600 calories from protein/ 5.65Kcal = 106gms.
  • 3000 calories x 20% = 600 calories from fat/9.4Kcal = 64gms.
  1. Drink lots! You should be drinking lots during the day. There’s a saying in endurance sports that’s really useful: Clear and Copious (refers to the color and quantity of your urine). The deeper the color of your urine, the more dehydrated you’re apt to be. Also, consider that toilet water dilutes the color and vitamin supplements brighten the color.

    During your training, especially your longer workouts, have fluids available. Have a water bottle available at the track. Carry one with you or stash one along the route of your longer runs. As a rule of thumb, drink at least 8 ounces every 20 minutes while training or racing and adjust this amount upward for hotter weather conditions. When racing, don’t pass those water stops. Practice grabbing a cup, squeezing the top of it between thumb and forefinger so it doesn’t splash out, and releasing a corner of the cup to let it run into your mouth while still running.

  2. Afraid of too much water! It is unfortunate that recent media attention to this subject, as a result of a fatality at the Boston Marathon, has lead to much confusion and misinterpretation. An athlete in Boston passed away from the effects of Hyponatremia- low blood sodium and not simply from “over-hydration” (a term overly simplified and used by the media).

    When we consume large amounts of water, we dilute the electrolytes in our bloodstream (sodium, potassium, calcium and magnesium). These electrolytes are required for proper neural transmission, muscle contraction, and equilibrium. In order to maintain proper electrolyte balance while hydrating,drink sports drinks in place of water and/or practice the use of electrolyte supplements in your training. Train with the fluid replacement drink that’s being used by your target “A” race if you know what it will be. If you’re mixing your drink from a powder, follow the directions carefully. A fluid replacement drinks should be Less than 8.0% sugar solution; otherwise it will upset your stomach due to its being slow to empty from your stomach. Properly mixed drinks will have a sugar solution of between 4.0% and 6.0%- a range that empties quickly from your stomach and provides some carbohydrate in addition to electrolytes.

Following a good nutrition plan will have a significant positive impact on your training and racing. The reverse is also true! Using the guidelines outlined in this article together with a good choice of nutrition sources will provide a good component, which together with consistent training, will help you reach your performance potential.


Chuck Graziano is an endurance sports coach who has written numerous articles on endurance training, which have been appeared in several publications including “Inside Triathlon” magazine. He is a USA Triathlon Expert Level (II) certified coach, is certified as a Level III coach by USA Cycling and is a Level III Alpine Ski Coach, as certified by the Professional Ski Instructors of America. For information about this article or other training questions, contact chuck@inspiredperformancecoaching.com