Sport Nutrition: Post-Workout Meals and Daily Protein intake
Once again, For those of you who do not like to read, or don’t like the science behind it all, here are the cliff notes. Sorry, no graphs today, but if you would like I will draw what some of this stuff looks like in person.
Key Points:
1. Ingesting any meal (liquid preferably) after a workout will replenish energy (glycogen) stores, grow and repair muscles, and enhance the immune system.
2. Carbohydrates (simple sugars are best) and protein (Whey) are needed in a ratio of about 3:1 or 4:1 and minimal fat for best results. Chocolate milk is a good, cheap option.
3. Daily protein intake likely should be much higher than the RDA. 1 gram of protein per lb of body weight may be a good marker.
4. Dividing protein intake into as many servings as possible is better for muscle and strength gain compared to a couple big meals because the protein will be absorbed better.
Introduction
In this article I am going to talk about the intake of Protein and Carbohydrates as they relate to exercise performance. We will largely discuss their use after exercise, but we will also look at how to optimally handle these Macronutrients throughout the rest of the day too. In the future, we will talk more about these nutrients and how to use them before and during exercise.
Protein and Carbohydrates After Exercise
The goal of Carbohydrates and Protein after exercise is to grow and repair damaged muscle and replenish energy stores (glycogen) for your next workout. Protein is mostly responsible for repairing muscle damage. The growth of muscle is determined by the ratio of protein synthesis (the building of muscle/protein) to protein degradation (the breakdown of muscle/protein). When you ingest protein, protein synthesis increases, thus allowing you to build muscle [1]. After exercise, especially weightlifting you are actually in a catabolic state because your body has been broken down from the work completed. We want to switch this breaking down of our muscles to a rebuilding process, and this is where food/liquid intake comes into play. The intake of protein directly after a workout will stimulate protein synthesis, thus allowing muscles to grow [1-3]. However, most people don’t realize that the addition of carbohydrates to the protein may further enhance protein synthesis, likely because of its effect on insulin [4]. Although Insulin is thought of as a bad hormone because it can make you store fat when you’re sedentary, it can also help drive carbohydrates and protein into muscle cells when your muscles need it (like after a workout). Newer research may suggest that ingesting carbohydrates may not affect protein synthesis significantly more than protein alone, but a carbohydrate and protein mixture will increase muscle glycogen (Energy stores in your muscles) more so than either alone [5, 6]. This will help you recover and become ready for your next day of exercise. So it is still likely beneficial to combine both of these post workout.The best types of carbohydrates are actually simple sugars (yes, this means you could eat candy). It is also important not to delay the intake of these nutrients because these effects will be diminished the longer you wait [7]. In this study (along with many others), after 12 weeks of strength training, taking a carbohydrate protein mixture directly after training resulted in significant greater muscle and strength gains than taking the mixture 2 hours later [8].
Protein Intake Throughout The Day
Protein intake for the rest of the day also becomes important because you want to continue to keep protein synthesis high. There are many varying opinions out there on how much protein one should ingest throughout the day to optimize protein synthesis, but it is very likely that the amount of protein needed is well above the Recommended Daily Allowance (RDA) of .8g/kg body weight (bw). Some have said that 1.8g protein/kg bw is sufficient for muscle growth [9]. Another showed that 3.3 g/kg bw was better than 1.3 g/kg bw [10] . The exact amount is not known, but there does appear to be some sort of plateau effect as more protein is consumed. There also is a limit to the amount of protein that you will benefit from in one sitting. Because your body can only absorb and use so much protein at a time it is important to spread this out as much as possible throughout the day (5+ meals/snacks) to cause a greater increase in Nitrogen balance (a way to measure muscle growth) [11]. Protein quality is also important. This refers to the amino acid composition of the proteins. If a source of protein has all the essential amino acids it will work much better in the body. To make it simple, whey protein powder, eggs, and meat are the best sources of high quality protein. Beans and nuts would be next on the list followed by other vegetable sources.
So how do you use this information?
Research generally agrees that post-workout meals (45min post) should have a mixture of carbohydrate to protein ratio of 3:1 or 4:1 for best results. For the average person, 20g of Protein powder (whey preferred because of it is quickly digested/absorbed) and 60-80g Carbohydrates (simple sugars prefered) may be enough while this can be adjusted slightly based on your size. Keep in mind that Protein and Carbohydrates have a caloric value too, so factor those numbers in when you are looking at daily calories ingested. It is also best to have this in a liquid form as it becomes digested faster. This can be accomplished with the use of supplements such as Gatorade and Whey protein powder, or chocolate milk will get you pretty close to this ratio too. If taken in a liquid form I also recommend to have another meal about an hour later to continue the constant protein influx. Eating a normal meal after workouts instead of a liquid meal isn’t optimal, but is still very beneficial compared to not having anything. Fat intake should be minimized in that first meal since it slows down digestion. For overall protein intake for a day, 1 gram of protein per lb of body weight may be a good number to aim for. If you get close to this number, then you should be pretty well set for optimizing muscle recovery. This should be divided throughout the day in as many servings as possible.
References
1. Biolo, G., et al., An abundant supply of amino acids enhances the metabolic effect of exercise on muscle protein. Am J Physiol, 1997. 273(1 Pt 1): p. E122-9.
2. Tipton, K.D., et al., Postexercise net protein synthesis in human muscle from orally administered amino acids. Am J Physiol, 1999. 276(4 Pt 1): p. E628-34.
3. Tipton, K.D., et al., Timing of amino acid-carbohydrate ingestion alters anabolic response of muscle to resistance exercise. Am J Physiol Endocrinol Metab, 2001. 281(2): p. E197-206.
4. Miller, S.L., et al., Independent and combined effects of amino acids and glucose after resistance exercise. Med Sci Sports Exerc, 2003. 35(3): p. 449-55.
5. Williams, M., et al., Effects of recovery beverages on glycogen restoration and endurance exercise performance. J Strength Cond Res, 2003. 17(1): p. 12-9.
6. Zawadzki, K.M., B.B. Yaspelkis, 3rd, and J.L. Ivy, Carbohydrate-protein complex increases the rate of muscle glycogen storage after exercise. J Appl Physiol (1985), 1992. 72(5): p. 1854-9.
7. Levenhagen, D.K., et al., Postexercise nutrient intake timing in humans is critical to recovery of leg glucose and protein homeostasis. Am J Physiol Endocrinol Metab, 2001. 280(6): p. E982-93.
8. Esmarck, B., et al., Timing of postexercise protein intake is important for muscle hypertrophy with resistance training in elderly humans. J Physiol, 2001. 535(Pt 1): p. 301-11.
9. Lemon, P.W., D.G. Dolny, and K.E. Yarasheski, Moderate physical activity can increase dietary protein needs. Can J Appl Physiol, 1997. 22(5): p. 494-503.
10. Fern, E.B., R.N. Bielinski, and Y. Schutz, Effects of exaggerated amino acid and protein supply in man. Experientia, 1991. 47(2): p. 168-72.
11. Dangin, M., et al., The digestion rate of protein is an independent regulating factor of postprandial protein retention. Am J Physiol Endocrinol Metab, 2001. 280(2): p. E340-8.