Performance Nutrition 101
Photo Credit: Cpl. Kenneth Trotter
You put a lot of effort into your workouts, both the planning and execution, but inadequate nutrition can undo all of your hard work. Optimal performance nutrition can help take your physical fitness to the next level, and also assist with recovery and injury prevention. Nutrition plays a major role in physical performance, including what you choose to eat and when you choose to eat. For example, a lack of nutrients prevents adequate repair of muscle tissue, and inadequate energy intake can lead to lean muscle breakdown.1 Although hydration strategies are not addressed in this article, they are also a crucial component of performance. Comprehensive, practical hydration strategies are available in the Navy Operational Fitness and Fueling System (NOFFS) Operational Fueling guide.
Building blocks for performance
An athlete may be someone who spends their off-time training for triathlons, endurance bicycle rides, or other athletic competitions, or they may be a tactical athlete who expends above-average energy in operational training. Regardless of their “sport” the diets of athletes do not need to be significantly different than the recommended Dietary Guidelines for Americans, so it is important to understand the basics of nutrition before discussing performance nutrition. The primary components of one’s diet are macronutrients and micronutrients. Macronutrients include protein, carbohydrates, and fat. Each macronutrient should be included in any athlete’s diet. Micronutrients include vitamins and minerals. These are needed in much smaller amounts than macronutrients, but are still necessary for optimal performance.1 We will briefly describe each macronutrient below, as well as provide a summary of micronutrients. Please note that any nutrition plan should consider the type of sport, the energy expended with each workout, and the volume of training. For example, someone competing in an Olympic lifting event will have different nutritional needs than an endurance cyclist. That same cyclist will also have different caloric needs depending on whether they are actively training for an event such as a century ride or in their training off-season.
In the past, there has been a misconception that protein is only important for athletes seeking to gain muscle mass, and that eating protein will build muscle. It is actually resistance exercises that increase muscle mass; protein is needed to rebuild and repair muscle cells. This is true in all athletes, not just those looking to build strength. Protein plays a key role in other parts of the body as well, including2:
- Assisting chemical reactions within the body
- Functioning as hormones to regulate processes throughout the body
- Fighting diseases
- Providing energy
The best diet includes an adequate amount of lean protein to meet the demands placed on the body; no more and no less. In fact, current literature indicates that more than 0.9 grams per pound of body weight of protein a day is not beneficial and may even be harmful.2 While individual needs will vary, the chart below provides some general guidelines. Because plant proteins are not digested as well as animal proteins, vegetarian athletes should increase their protein intake by about 10%. To ensure you are eating lean proteins, follow this rule of thumb: the fewer legs on the animal it came from, the better it is for you! The dairy products and lean beef from a four-legged animal is good, meat and eggs from a two-legged bird are better, and the healthy fats that complement the protein in fish make it a great choice.
Table 1: Protein Recommendationsa
0.4g per pound of body weight
64g of protein
0.55-0.6g per pound of body weight
88-96g of protein
aAdapted from Comana et al., 2013. bTo calculate body weight in kilograms (kg), divide body weight in pounds by 2.2. For example, a 160lb individual weighs = 160/2.2 = 72.7kg.
Carbohydrates are the primary source of energy for the body and brain, and are necessary to completely metabolize fats and protein. Carbohydrates are stored as glycogen in the muscles and the liver. Muscle glycogen is used for physical activity and liver glycogen is stored to maintain normal blood levels and be used by the body when needed. Active individuals need adequate amounts of carbohydrates because if the body runs low on glycogen, it will begin to break down protein to manufacture glucose.2
There are two forms of carbohydrates, simple (sugars) and complex (starches and dietary fiber). Simple sugars lead to a quick jump in blood glucose and starches and fibers have a more lasting effect: it takes time for the body to break down the complex carbohydrates into single sugars so they can be absorbed.2 This concept is important to consider when developing pre-workout strategies; in the hour before an event simple sugars, preferably those with nutritional value such as fruit/fruit juice that also contain necessary electrolytes, should be consumed so they are readily available for energy.
Carbohydrate needs will vary greatly among individuals. A general guideline to follow is to get 45-65% of total daily calories from carbs. For example, if an endurance athlete consumes 3,000 kcal per day, it would be reasonable for 60% of those calories to come from carbohydrates. This would equate to 1,800 kcal, or 450 grams, of carbohydrates.
Carbohydrates that are consumed on a regular basis, meaning they are not being eaten as a pre-workout or during-workout snack, should be as “clean” as possible. The Navy Operational Fitness and Fueling System (NOFFS) provides a useful tip for eating clean carbs: “think brown and found close to the ground!”
Dietary fat is a crucial element of an athlete’s diet as fat serves as an energy reserve for the body. Fats perform other roles in the body, including2:
- Manufacturing hormones
- Transport of substances, including triglycerides and fat-soluble vitamins
- Structural support to brain and nerve cells
- Insulation against cold
Not all fats are created equal. The majority of dietary fats can be broken down into saturated fats, which have limited nutritional value, and unsaturated fats, which can benefit a performance nutrition plan. Saturated fats are found in foods such as high-fat meats, cheeses, butter, and coconut oil. A good way to recognize saturated fats are that they solidify at room temperature. For many years, saturated fats have been linked to heart disease,3 and although there is emerging research that saturated fats may not damage the heart as much as was once thought, they should still be consumed in moderation due to the high caloric content (nine calories per gram of fat).
Unsaturated fats include omega-3 and omega-6 fatty acids. While omega-3 fatty acids have been touted as having anti-inflammatory properties and being protective of the heart, omega-6 fatty acids have been shown to promote inflammation. It is important to not remove omega-6 fatty acid sources from the diet completely, however. The balance between omega-3 and omega-6 fatty acids is essential to good health, so while increasing omega-3 fatty acid intake and lowering omega-6 fatty acid intake is encouraged, neither should be eliminated from the diet.2 All athletes should strive for 20-35% of their diet to come from fats, with no more than 10% of that from saturated fats.1
Micronutrients include vitamins and minerals, and play an important role in1:
- Energy production
- Bone health
- Immune function
- Preventing tissue damage
- Repair and rebuilding of muscles during exercise recovery
Regular or intense exercise can increase the need for micronutrients, making it important for athletes to not just eat, but eat well. Listed below are key micronutrients that are important to an athlete’s diet and examples of foods that contain the nutrients:
- Calcium - dairy products and leafy green vegetables
- B vitamins – fruits and vegetables, whole grains, beans
- Vitamins C and E, Beta Carotene, Selenium – citrus fruits, vegetables, nuts and seeds, seafood
- Iron, Zinc, and Magnesium – lean meats, seafood, vegetables, beans, nuts, dairy products
- Vitamin D – fatty fish, fortified foods
- Sodium and Chloride - table salt, sports drinks
- Potassium – fruits, vegetables, nuts
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 FDA 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.
For more information on supplement safety, visit Operation Supplement Safety (OPSS). OPSS is 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 better understand the data on dietary supplements.
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:
- Current health status
- Type of sport or activity
- Individual nutrient needs
- Food preferences
- Current body weight, and body composition goals
For guidance on pre-, during-, and post-workout nutrition, check out our Fueling Your Workout article. Athletes seeking additional information and meal building tools can check out the NOFFS Operational Fueling Guide or download the NOFFS mobile app, available on iTunes. The following websites also contain additional resources:
- The Navy and Marine Corps Public Health Center Active Living page offers you resources to help keep you active so that you can be at your prime physically, psychologically and operationally.
- The Navy and Marine Corps Public Health Center Performance Nutrition page provides educational resources and materials to help you select nutrient dense, healthy food for optimal performance.
- The Human Performance Resource Center Nutrition page provides information enabling warfighters to meet their nutritional demands.
- The Department of Defense’s Operation Live Well website contains tools, resources and original content like cookbooks, which you can use to adopt or maintain a healthy lifestyle.
1. 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.
2. Comana F, Seebohar B, Barefield K. NASM’s Guide to Sports Nutrition. Assessment Technologies Institute, LLC; 2013.
3. Centers for Disease Control and Prevention. Saturated fats. http://www.cdc.gov/nutrition/everyone/basics/fat/saturatedfat.html. Updated October 4, 2012. Accessed April 9, 2014.