These are the Carbs You Should Eat Before a Workout

By John Hansen | Sept. 04, 2018, 1:29 p.m. (ET)

Fueling before a workout

There are many essential elements to your multisport training but often aspects such as nutrition take a back seat to workouts, leaving athletes to wonder why their training and racing are suffering. To be a complete athlete, focus on nutrition planning which is both a daily process and specific to pre, during and post workouts. 

When considering pre-workout nutrition, poorly planned meals, snacks and hydration can interfere with the quality of your training. This is particularly true of the long course triathletes who often train for three-plus hours.

The following information is to be used as a guideline to develop better fueling and hydration behaviors that will assist you in managing your nutrition requirements prior to your training sessions. Long course triathletes, pay particular attention to getting adequate intake levels prior to very long workouts.

Recommendations

The goals for fueling before a training session is to ‘top off’ carbohydrate stores, optimize fluid intake to prevent dehydration, maintain blood sugar levels and delay depletion of stored glucose (carbohydrates) in muscles and the liver during the workout.

To begin, it is important the last full meal should be eaten outside of four hours from the start of the workout. When you begin exercising, blood rushes to working muscles so blood rushing away from the stomach to those muscles does not allow for proper digestion of that meal during exercise, which may result in GI issues, a faster drop in blood sugar and limited performance.  

To ensure your fuel is ‘topped off’ prior to your workout, a triathlete should ideally have a low fat, light  protein, high carbohydrate easily digestible mini-meal or snack (300-700 calories) within 1-3 hours prior to the training session. More specifically, since carbohydrates are the primary source of pre-workout calories, they are generally solid and should be consumed at a level of 0.25-0.4 grams per pound for each hour prior to activity depending the duration and intensity of the workout. Long course triathletes, prior to a three-plus hour workout, should consume more carbohydrates but starting about three hours out from the workout.  

A 155-pound long course triathlete, for example, who plans to ride for three hours, and is going to train three hours from now could consume as much as 174 grams of carbohydrates or 696 carbohydrate calories (155 lbs x 0.35 g/lb = 58 grams x 3 hrs x 4 Calories per gram of carbohydrate = 696 calories). 

With a small amount of calories from fat and protein, the total calories may be around 800 – the equivalent of a peanut butter and jelly sandwich, a large handful of pretzels, a large banana and 8 oz of fruit juice. This same person may only consume 270 calories if the workout is one hour from now.  

As the workout draws closer, the rule of thumb is to consume more liquid calories and fewer total calories to allow for better digestion, reducing GI complications, but the above formula can still apply to your nutrition planning. If you are within an hour of the workout you should consume just a small snack of 150-300 calories with the same balance of carbohydrates, proteins and fats as above or just all carbohydrates. These calories can also just come from a liquid carbohydrate source such as a sport drink if you do not tolerate solid foods well just before a workout.

Since the primary source of calories consumed prior to a workout is carbohydrates, options should be easily digestible and more complex. 

Examples include most fruit (except apples), bagels, energy bars, breads, whole grain crackers/cereal, rice, and/or yogurt. One of my favorite mini-meal selections, which I recommend to my athletes to eat within an hour of the workout, includes a 1 tsp of all natural peanut butter spread on a banana and a handful of whole wheat crackers with 8 ounces of water. 

Remember to avoid high fiber foods, too much dairy and high protein options such as meats which are difficult to digest the closer the workout is to starting.  

These values can vary in the recommended range depending on personal food tolerance, individual experience and when the previous full meal was eaten. Triathletes should assess how they feel and perform during longer workouts making adjustments as needed in terms of volume and food choices. 

For instance, if your training is first thing in the morning, it may be necessary to emphasize an all fluid fueling regimen immediately upon waking.

Furthermore, the session should begin with you optimally hydrated, which is on-going process to ensure a quality workout. Half your body weight in ounces is a good reference point.

So using our athlete above, he would be consuming 78 ounces of fluid, mostly water, per day.  

Sticking with a formula driven assessment, athletes should drink 0.07-0.10 ounces of fluid per pound of body weight at least four hours before a workout and 0.04-0.10 ounces per pound, two hours before a workout.

Furthermore, athletes should consume 15-20 ounces of fluid in the 30-60 minutes pre-workout and 6-10 ounces of fluid 15-30 minutes pre-workout without it having detrimental effects on the workout.  

Variations to these hydration recommendations may be needed if the workout is a run and the athletes cannot tolerate these levels of fluid in the gut or if it is hot and or humid which means these fluid intake levels should be at the top of the range.  

Proper fueling and hydrating is essential to a quality workout routine and by applying the above information into your daily training regime you will be taking additional steps towards optimizing your abilities as an athlete.  

John Hansen, USAT, and USA Swimming Level 1 Coach and USA Cycling Level 3 Certified coach, Folsom California, with 23 years of coaching experience. Hansen has an MS in Exercise Physiology and previously worked at the UC Davis Sports performance lab for five years. Hansen has coached athletes from beginner to pro level, competing at many major US Age Group National Championships and World Championships, as well as the US Men's Pro championships. Hansen currently coaches the UC Davis Collegiate Club Triathlon team with multiple teams placing in the top 12 and several athletes placing in the  top 20, in the past eight years at the Collegiate Club National championships.

Hansen also has his own coaching business, primarily coaching long course athletes, 70.3 and 140.6. Visit HansenMutlisport.com or email john1hansen@sbcglobal.net.

The views expressed in this article are the opinion of the author and not necessarily the practices of USA Triathlon. Before starting any new diet or exercise program, you should check with your physician and/or coach.

References

Coleman, Ellen. Eating for Endurance, 4th edition. Bull Publishing. 2003.

Ryan, Monique. Sports Nutrition for Endurance Athletes, second edition. VeloPress, 2009.

McArdle, WD, F.I Katch, V.L. Katch. Sports and Exercise Nutrition. 3rd ed. Baltimore, MD: Lippincott Williams & Wilkens. 2009.

USAT – Level 1 Coaching Manual Nutrition Science for the Multisport Athlete, Jennifer Hutchins and Sports Nutrition for Triathlon Coaches, Bob Seebohar, 2017