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FUELING YOUR WORKOUT
Photo Credit: Lance Cpl. Crystal Druery
In Performance Nutrition 101 we discussed the building blocks to optimal performance nutrition. Maintaining a balanced, healthy diet will provide adequate energy to carry out activities throughout your day, repair from your last workout, and even perform a light to moderate 30- to 60-minute workout. If your next training session is going to last more than 60 minutes, additional energy will be needed before and during the workout to fuel your exercise, while careful consideration must be given to what is consumed immediately after to allow for optimal recovery. Below are some general guidelines and strategies to enhance your exercise efforts.
A pre-workout snack or meal is most beneficial if it contains a mix of carbohydrates and protein. Carbohydrates will provide energy for the workout, and current research indicates consuming protein before exercise can assist in replenishing glycogen after exercise and contribute up to 15% of energy used during exercise.1 Below are some general guidelines for pre-exercise nutrition. The recommendations provided are intended for athletes who will be training intensely for at least 90 minutes. The total calories should be decreased for less intense workouts or workouts of shorter duration.
Table 1: Pre-Workout Nutritiona
Daily recommendation for a 160lb (72.7kg)b individual
4 hours before exercise
Up to 1.8g per pound of body weight of carbohydrates (CHO) and up to 30g of protein
PB&J sandwich on wheat, 1.5 oz. pretzels, banana, 16 oz. sports drink (106g CHO, 20g protein)
2 hours before exercise
Up to .9g per pound of body weight of CHO and approximately 20g of protein
Sandwich with two slices of bread and 2 tbsp. all natural peanut butter, banana, 8-oz. glass of low-fat milk (68g CHO, 21 g protein)
Up to .5g per pound of body weight of CHO and a small amount of protein
Banana with an ounce of almonds (30g CHO, 6g protein)
aAdapted from Comana et al., 2013 and Rodriguez et al., 2014. b Nutrition content is approximate.
The carbohydrates in a pre-workout snack should be simple carbohydrates that will be readily available for fuel. It will be very important to practice pre-workout nutrition strategies during training to learn what types of foods your body can handle and what it has trouble digesting. For instance, if the amount of food required to meet the recommended ranges causes gastrointestinal upset during the workout, liquid sports drinks or smoothies may be a better option.
The primary goal of nutrition during workouts is to ensure muscle glycogen and blood glucose levels, or energy, are available throughout the event. People are able to tolerate different amounts and types of food during exercise, so trying different strategies while training is important. Replacing calories during workouts is generally only necessary if the event will last more than 60 minutes and is best accomplished by consuming carbohydrates.1 Research on the benefits of consuming protein during exercise is inconclusive. It is also worth noting that much of the research done regarding nutrition during workouts has been conducted on endurance, aerobically-trained athletes. It is possible that some of the resulting recommendations are therefore not applicable to strength and power athletes, such as those participating in fitness competitions, and team sport athletes, making it even more essential for these individuals to speak to a nutrition expert to determine individual needs.
Individuals exercising for greater than 60 minutes should consume between 30 and 60 grams of carbohydrates per hour, as this has been shown to extend endurance performance.2 This can be accomplished by eating easily digestible foods or by drinking a sports beverage that contains carbohydrates in addition to electrolytes. If sports gels are selected, it is important to adequately dilute the gels by drinking at least eight ounces of water following consumption. Dilution is necessary because carbohydrate concentrations greater than 8% have been shown to cause bloating, GI distress, and diarrhea; most gels have carbohydrate concentrations in excess of 60%.
The main purpose of nutrition post-workout is to adequately replace fluids, electrolytes, energy, protein, and carbohydrates to replace glycogen stores, repair muscle tissue, and assist with recovery.2 An easier way to remember this is to refuel with carbohydrates, rebuild with proteins, and rehydrate with fluids.3 This is especially important if another workout is planned for later that day or the next day. General guidelines recommend about .5 grams of carbohydrates per pound of body weight within 30 minutes of completing a long (greater than 90 minutes) or intense workout, and then again every two hours after for up to six hours.2 Smaller amounts of protein should be included as well. Sound complicated? Simplify it by keeping the carbohydrate to protein ratio between 2:1 and 3:1.
Table 2: Example Fueling Strategya
See Table 1
Up to 30 grams as tolerated
30-60 grams per hour
1 gram per every 3-4 grams CHO if training lasts longer than 90 minutes
.5 grams per pound of body weight every 2 hrs. for up to 6 hrs.
Up to .25 grams per pound of body weight every 2 hrs. for up to 6 hrs.
aAdapted from Comana et al., 2013.
Some athletes may find it difficult to eat immediately before, during, or after exercise and turn to products such as protein shakes or powders, meal replacement bars, or sports gels to provide energy and nutrients. While these can be an effective alternative, it is crucial to be an informed consumer and look for reliable sources of information on dietary supplements to evaluate the product claims. A great place to start is Operation Supplement Safety, a program sponsored by the Human Performance Resource Center at the Uniformed Services University of the Health Sciences to help service members and their families sort through the data on dietary supplements.
Other athletes may use dietary supplements in an effort to enhance performance. Dietary supplements are products that contain one or more ingredients, such as macronutrients (carbohydrate, protein, fat), vitamins, minerals, herbs, amino acids, enzymes and metabolites, intended to complement the diet. However, dietary supplement products are not evaluated by the Food and Drug Administration before distribution. By law, manufacturers must ensure their products are safe before they hit the store shelves. Because of this industry’s self-regulation, it is important for Sailors and Marines to exercise due diligence when considering whether or not to use dietary supplements. This includes discussing the supplement with their healthcare provider, looking for third party certification on the label, using reputable brands and taking no more than what is recommended. High risk supplement categories that require extra caution include body building, weight loss, diabetes and sexual enhancement products.
Dietary supplements are many times unnecessary. Eating a balanced diet with a variety of food choices will provide what you are purchasing in dietary supplements naturally. Food is easier on your budget, provides energy and minimizes or eliminates the potential for adverse health outcomes.
As with the information provided in Performance Nutrition 101, this article is intended to provide general guidance for active adults and competitive athletes, but nothing can replace the tailored advice of a dietitian or sports nutritionist. There are many variables that should be considered when developing a nutrition plan including:
Athletes seeking additional information and meal building tools can check out the Navy Operational Fitness and Fueling System Meal Builder or download the NOFFS mobile app, available on iTunes. The following websites also contain tools to assist with the planning and tracking of macro- and micronutrients:
1. Comana F, Seebohar B, Barefield K. NASM’s Guide to Sports Nutrition. Assessment Technologies Institute, LLC; 2013.
2. Rodriguez N, DiMarco N, & Langley S. Nutrition and athletic performance. Medicine & Science in Sports & Exercise. 2009;41(3):709-731. http://journals.lww.com/acsm-msse/Fulltext/2009/03000/Nutrition_and_Athletic_Performance.27.aspx. Accessed March 25, 2014.
3. Navy Fitness. Navy operational fueling. http://www.navyfitness.org/_uploads/docs/NOFFS_Nutrition.pdf. Accessed April 1, 2014.
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