If you’ve looked closely at your grocery bill you may have noticed the prices increasing with every visit. This is especially true for the “essentials”, including protein-rich food sources (i.e. meat, poultry, fish, dairy and peanut butter), fruits and vegetables. In 2011, the average increase in price was upwards of 10 percent (U.S. Department of Agriculture). For those of you who are very active, and require more protein in your diet, this can get extremely expensive. To make protein shopping more affordable and convenient, protein powders and supplements are an economical choice to ensure you get the amounts of quality protein that you need. Although protein powders can be used a variety of ways the most common use is in the form of protein shakes and drinks.
When it comes to protein powders and supplements there are a lot of questions including the following:
- How much protein do I really need (i.e. sedentary, moderately active, very active)?
- What type of protein powder is best?
- Do I really need protein supplements (i.e. branched-chain amino acids)?
- What should I include in my protein shakes?
The International Society of Sports Nutrition (ISSN) has outlined recommendations for protein and exercise that answers these questions.
The Importance of Protein
Protein is an important part of a healthy diet to ensure proper body function and to prevent disease. In fact, the human body is made up of about 45 percent protein. Without protein our bodies wouldn’t be able to repair, regulate or protect itself.
Proteins, unlike other essential nutrients, are essential for overall good health. They are the building blocks of life and have a number of functions in the body, including the following:
- Building and repair of body tissues (i.e. muscles, tissues, organs, etc.).
- Enzymes, hormones and immune molecules (i.e. antibodies) are proteins.
- Water balance, nutrient transport and muscle contractions require protein to occur.
- As a source of energy.
- To keep skin, hair and nails healthy.
Protein Intake Recommendations
The Food and Nutrition Board currently recommends 0.8 grams of protein per kilogram of body weight per day for healthy adults. Individuals who engage in physical activity/exercise require higher levels of protein intake than 0.8 grams/kilogram of body weight/day, regardless of the type or intensity of the exercise. Insufficient protein intake can lead to muscle loss and slower recovery from exercise. The ISSN recommendations for protein intake include:
- Physically Active (including sports activities) – 1.4 to 2.0 grams/kilogram of body weight per day
- Endurance Exercise – 1.0 to 1.6 grams/kilogram of body weight per day
- Strength/Power Exercise – 1.6 to 2.0 grams/kilogram of body weight per day
The amount of protein intake depends on exercise intensity and duration of the exercise. The higher the intensity and/or duration, the greater the amount of protein required.
Protein Powder Recommendations
The ISSN recommends that individuals engaging in exercise attempt to obtain the majority of their protein through whole foods. Whey and casein powders are recommended due to their high protein digestibility corrected amino acid score (PDCAAS) and ability to increase muscle size.
The U.S. Dairy Export Council’s Reference Manual for U.S. Whey and Lactose Products (2003) indicates that milk-derived whey protein isolate presents the highest PDCAAS out of all of the common protein sources due to its high content of essential and branched chain amino acids. Milk-derived casein, egg white powder, and soy protein isolate are also classified as high quality protein sources with all of them scoring a value of unity (1.00) on the PDCAAS scale.
Whey and casein proteins are used differently due to the speed at which the body digests them. In studies comparing whey and casein protein for increasing muscle mass, whey protein was the clear winner. Whey protein taken immediately after exercise has been shown to increase muscle mass. This is primarily due to the fact that the body digests whey protein quickly, making it more readily available for protein synthesis and rebuilding muscle. On the other hand, including casein protein in the diet (taken in the later evening or before bedtime) may preserve muscle mass and promote recovery during sleep because of the slower digestion time and longer lasting effect.
Protein Timing Recommendations
The ISSN recommends that exercising individuals should consume high quality protein before, during and after exercise. This is because of protein breakdown that occurs during exercise and the need to rebuild muscle during recovery. A strategically planned protein intake timed around physical activity is important for:
- Preserving muscle mass
- Promoting muscle hypertrophy (growth)
- Ensuring proper recovery from exercise
- Sustaining optimal immune function
In numerous studies, protein and carbohydrates taken before and/or right after exercise have been shown to increase protein synthesis (building of muscle).
The Role of Branched-Chain Amino Acids (BCAA) in Exercise
Branched-chain amino acids (i.e. leucine, isoleucine and valine) make up approximately one-third of skeletal muscle protein. An increasing amount of literature suggests that leucine appears to play the most significant role in stimulating protein synthesis. The ISSN supports the use of amino acid supplementation (particularly BCAAs) for active and exercising individuals.
Because BCAAs have been shown to aid in the body’s ability to recover from exercise (i.e. stimulating protein synthesis, aiding in glycogen re-synthesis, delaying the onset of fatigue, maintaining mental function in aerobic-based exercise) the ISSN suggests consuming BCAAs (in addition to carbohydrates) before, during and after exercise. It has been suggested that the RDA for leucine should be 45 milligrams/kilogram of body weight per day for sedentary individuals, and even higher for active individuals. BCAAs should be obtained from whole food protein sources (i.e. animal protein) when possible.
What to Include in a Protein Shake
Protein shakes are the most common way to incorporate protein powder into your diet. A well-balanced protein shake should include the following:
- High quality protein (i.e. whey, casein or soy)
- Simple carbohydrates (a variety of fruits)
- Nutrient-dense liquid base (i.e. milk, almond milk, soy milk or coconut water)
Optional ingredients may include:
- Branched-chain amino acid supplement
- Vegetables (i.e. spinach, kale, beets, carrots)
- Coconut oil (i.e. lauric acid; 1 to 3 tablespoons is suggested per day)
Keep in mind that a protein shake is “concentrated” nutrition that will require adequate hydration to ensure proper absorption and utilization of the nutrients. This is especially important if you are adding supplements (i.e. creatine) that require more hydration than usual. It is difficult to determine how much water a person should drink but a suggested guideline is to drink 8 ounces of water every 15 minutes while training and after a post-workout shake to avoid dehydration.
For more information on the International Society of Sports Nutrition and the Protein and Exercise Recommendations click here.