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Sunday
Aug162009

Get the Most Out of Your Workout: Nutrient Timing Part 3

Written by Tom Nikkola - Director of Nutrition & Weight Management

In Part 1 and Part 2, we discussed the importance of nutrition and its influence on hormones around your workout. We also covered what to eat before and during your workout to decrease muscle protein breakdown and increase muscle protein synthesis. In today's post, we'll look at post-workout nutrition. Post-workout nutrient intake has received the most attention in the past. It is certainly an important aspect to optimal recovery. As we discussed in the first two parts, post-workout nutrition can be enhanced by proper pre-workout and during-workout nutrient intake.

During a workout, even with proper nutrient intake, glycogen levels are reduced and muscle tissue breaks down from the stress of the workout. Free radicals are also produced and a suppression of the immune system may take place. These changes are a normal part of an intense workout. If nutrient intake after exercise is neglected, the stress responses that takes place can have a negative effect on recovery.

An intense training session results in reduced muscle protein synthesis and increased muscle protein breakdown. When protein synthesis is reduced, and protein breakdown is increased, the result is a negative protein balance, meaning protein is breaking down faster than it is being built back up. Carbohydrate and protein intake each play a unique role in affecting net protein balance. Low-intensity base training may not significantly decrease glycogen stores or result in significant muscle tissue damage. In the case of aerobic activity, or lower-intensity exercise, it may be best to focus on a post-workout meal composed of more whole-food proteins and fibrous carbohydrates.

Protein's Role in Recovery

Protein, specifically the branched chain amino acids (leucine, isoleucine, valine), has been shown to quickly and dramatically increase protein synthesis after an exercise session. Amino acids "turn on" protein synthesis. Along with "turning on" protein synthesis, it is important to have sufficient protein available for tissue remodeling or the rebuilding of muscle protein. Whey protein is an ideal protein post-workout because of its high BCAA content and speed of digestion. Whole-food sources of protein may not work as well immediately following a training session because they take much longer to digest. Whey protein is usually digested within 30-60 minutes, whereas it can take whole-food protein 3-6 hours for digestion. This is well past the post-workout window of opportunity for nutrient intake.

In the case of a lower-intensity training session, consuming a high-quality protein source like whey protein alone may be sufficient to result in a positive net protein balance, meaning muscle protein is being synthesized faster than it is being broken down. In the case of a high-intensity training session, the increased muscle protein synthesis that results from proper protein intake, may not be enough to offset the results of the increased protein breakdown, which is most affected by the body's insulin production. In this case, carbohydrate intake also becomes critical.

Carbohydrate's Role in Recovery

Though working toward the same purpose, carbohydrate and protein act somewhat independently of one another to increase net protein balance. Carbohydrates role in post-workout nutrition is to increase insulin levels. Insulin secretion is stimulated by protein intake, but much more so by the intake of carbohydrates, especially simple carbohydrates. As insulin is secreted, it reduces the secretion of catabolic hormones, which reduces muscle protein breakdown. This is the one time during a person's day when it can be good to quickly raise insulin levels. Generally, high insulin levels are associated with increased fat storage and reduced ability to burn fat. However, immediately following an intense exercise session, the same hormone that increases fat storage also increases amino acid and glucose uptake into the muscle, and reduces the breakdown of protein and glycogen. During the short window of opportunity, it is advantageous to raise insulin levels. Remember, if this window is missed, consuming high-carbohydrate foods later in the day will not have the same effect. Later in the day the results may be increased fat storage, reduced ability to burn fat and swings in blood-sugar, which can cause cravings for even more carbohydrates.

Putting it all Together

To summarize your post-workout nutrition plan:

  • Be sure to consume in less than 45 minutes. Ideally, the sooner you can take in your post-workout nutrition, the better. Once the body is past its 45-minute window, it begins to respond more like it would without having completed a workout. This is important because the body will respond less favorably to carbohydrate intake once this "window of opportunity" has passed.
  • Your recommended nutrient intake varies based on the type and intensity of your workout, and your personal fitness goals.  Initial research showed that a 4:1 ratio of carbohydrate to protein was optimal. However, for those interested in general fitness or maintaining optimal body fat percentages, using only this ratio may result in over-consumption of carbohydrate and under-consumption of protein. Ratios ranging from 1:1 to 4:1 may be appropriate. Other studies have suggested a range of 0.8 to 1.2 grams per kilogram bodyweight for carbohydrates and 0.2 to 0.4 grams per kilogram bodyweight for protein. Since too much carbohydrate can result in increased fat storage, 0.8 g/kg or less of carbohydrate and 0.4 g/kg of protein may be more appropriate. For endurance athletes at appropriate body fat levels, carbohydrate intake at the higher end of the range will likely be beneficial.
  • Drink your post-workout meal, and eat a whole-foods meal a couple of hours later. A shake with whey protein and simple carbohydrates is ideal immediately following a training session. Whole food is better a couple of hours later. If you're stopping into LifeCafe to have something made, order up a Fast Fuel or something similar for immediately after the workout. Pick up something like the California Chicken Sandwich or a House Salad with Chicken to take with you for a couple of hours later. Consuming them together may be too many calories at one time, and will also slow the absorption of nutrients from consuming whole-foods along with the shake. Your post-workout shake should be as close to fat-free as possible to ensure optimal digestion takes place.

Exercise results in a host of benefits to the body, but those benefits can only be realized if the proper building blocks are provided. The basic building blocks of amino acids and glucose are critical to proper exercise recovery. Exercise recovery is where the real changes take place that come from a great workout. Other supplements, such as antioxidants, glutamine, creatine, beta-alanine and electrolytes can further enhance the results of a solid exercise program, but not without providing for the basic macronutrient needs first. We'll look at some of these additional supplements in the future.

Go to: Get the Most from Your Workout: Nutrient Timing Part 1

Go to: Get the Most from Your Workout: Nutrient Timing Part 2

References

Ivy, John and Robert Portman. Nutrient Timing. Laguna Beach, CA: Basic Health Publications, Inc. 2004

Kersick C, Harvey T, Stout J, Campbell B, Wilborn C, Krieder R, Kalman D, Ziegenfuss T, Lopez H, Landis J, Ivy J, Antonio J. International Society of Sport Nutrition position stand: Nutrient timing. J Int Soc Spor Nut. 2008

Antonio J, Ziegenfuss T. The Role of Nutrient Timing in the Adaptive Responses to Heavy Resistance Training. National Strength and Conditioning Association Hot Topic

McDonald, Lyle. Ultimate Diet 2.0. Salt Lake City, UT: Lyle McDonald Publishing. 2003

Carraro F, Stuart CA, Hartl WH, Rosenblatt J, Wolfe RR. Effects of exercise and recovery on muslce protein synthesis in human subjects. Am J Physiol Endocrinol Metab 259:E470-E476, 1990

Kimball S, Farrell P, Jefferson L. Exercise Effects on Muscle Insulin Signaling and Action. J Appl Physiol 93:1168-1180, 2002

Kumar V, Atherton P, Smith K, Rennie M. Human muscle protein synthesis and breakdown during and after exercise. J Appl Physiol 106:2026-2039, 2009

Biolo G, Williams B, Fleming RY, Wolfe RR. Insulin Action on Muscle Protein Kinetics and Amino Acid Transport During Recovery After Resistance Exercise. Diabetes 48:949-957, 1999

Berardi, J. The Importance of Post Workout Nutrition. www.johnberardi.com

Tipton K, Rasmussen B, Miller S, Wolf S, Owens-Stovall S, Petrini B, Wolfe RR. Timing of amino acid-carbohydrate ingestion alters anabolic response of muscle to resistance exercise. Am J Physiol Endocrinol Metab 281:197-206, 2001

Levenhagen D, Gresham J, Carlson M, Maron D, Borel M, Flakoll P. Postexercise nutrient intake timing in humans is critical to recovery of leg glucose and protein homeostasis. Am J Physiol Endocrinol Metab 280:E982-E993, 2001

This article is not intended for the treatment or prevention of disease, nor as a substitute for medical treatment, nor as an alternative to medical advice. Use of recommendations in this and other articles is at the choice and risk of the reader.

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