Timing of Eating and Exercise (Basic)

Introduction

An important area in the realm of sports nutrition is the timing of food and fluid consumption around exercise. In general, nutrition guidelines for athletes for each of the macronutrients are as follows: 6-10 grams carbohydrate per kilogram body weight per day, 1.2- 1.7 grams protein per kilogram body weight per day, and 20%-30% of total daily energy from fat (Rodriguez et. al 2009). The specific recommendations for each time frame surrounding exercise are detailed below.

Before Exercise

Eating before exercise has been shown to improve exercise performance when compared to exercising in a fasted state (Maffucci and McMurray 2000, Jentjens et al. 2003, Mosely et al. 2003). In regard to the composition of the pre-exercise meal or snack, it is recommended that it be high in carbohydrates, low in fat, moderate in protein, low in fiber, provide adequate fluid, and be familiar to the athlete (Rodriguez et. al 2009).

In general, larger meals can be consumed when there is a greater time gap between eating and exercise, whereas smaller amounts should be consumed if eating and exercise are in close proximity. In terms of carbohydrate, it is recommended that 1-4 grams carbohydrate per kilogram body weight be consumed 1-4 hours prior to exercise (Sugiura and Kobayashi 1998). For fluid needs, at least four hours prior to exercise it is recommended that water or a sports drink be consumed in the amount of approximately 5-7 milliliters per kilogram body weight (Rodriguez et. al 2009).

During Exercise

Fueling during exercise is of greatest importance during prolonged exercise. For exercise bouts lasting less than 45-60 minutes, water is generally sufficient. However, endurance performance has been shown to be benefited with drinking sports beverages that contain 6-8% carbohydrate during exercise (Coggan and Coyle 1991, Nicholas et al. 1995, Jeukendrup et al. 1997). For events lasting longer than one hour it is recommended that carbohydrate intake be in the range of 30-60 grams carbohydrate per hour, or 0.7 grams carbohydrate per kilogram body weight per hour (McConell et al. 1996, Currell and Jeukendrup 2008). Carbohydrates may be obtained from food, gels, or sports beverages, the latter option also providing needed fluid.

In regard to fluid intake during exercise, specific general recommendations for fluid replacement during exercise have not been established, as these general guides would likely be inappropriate for many situations (Sawka et al. 2007). Thus, fluid intake should be determined for each athlete individually based on the length of exercise, sweat rate, and opportunities to drink (Rodriguez et. al 2009).

After Exercise

The period immediately following exercise is a time when the body is best positioned to restore glycogen (the storage form of carbohydrates in the body) at the highest rate (Sugiura and Kobayashi 1998). It is recommended that carbohydrates be consumed within 30 minutes after exercise and that 1.5 grams carbohydrate per kilogram be consumed in the first hour following exercise (Ivy et al. 1988, Sugiura and Kobayashi 1998). Adding protein as part of a meal after exercise may be beneficial in regard to muscle protein synthesis and repair (Rodriguez et al. 2007, van Loon et al. 2013). In regard to specific amounts or time frames for protein ingestion surrounding exercise, additional research is needed (van Loon et al. 2013).

If recovery time is not limited, normal meals, snacks, and water intake should be sufficient to replenish fluids lost. In situations where recovery time is limited, or there is excess dehydration, 1.5 liters of fluid for each kilogram of body weight lost should be consumed (Sawka et al. 2007).

Conclusion

When attempting to meet nutrition needs, the timing of eating surrounding exercise is an important consideration. Appropriate meal timing and composition before, during, and after exercise can assist in improving athletic performance.

By: Jamie Saunders, University of Utah

Read the more technical details of timing your food intake around exercise.

Literature Cited

Coggan, A. R., and E. F. Coyle. 1991. Carbohydrate ingestion during prolonged exercise: Effects on metabolism and performance. Exerc Sport Sci Rev 19:1-40.

Currell, K., and A. E. Jeukendrup. 2008. Superior endurance performance with ingestion of multiple transportable carbohydrates. Med Sci Sport Exerc 40:275-281.

Ivy, J. L., A. L. Katz, C. L. Cutler, W. M. Sherman, and E. F. Coyle. 1988. Muscle glycogen synthesis after exercise: Effect of time of carbohydrate ingestion. J Appl Physiol 64:1480-1485.

Jentjens R. L., C. Cale, C. Gutch, and A. E. Jeukendrup. 2003. Effects of pre-exercise ingestion of differing amounts of carbohydrate on subsequent metabolism and cycling performance. European Journal of Applied Physiology. 88:444-452.

Jeukendrup, A., F. Grouns, A. J. Wagenmakers, and W. H. Saris. 1997. Carbohydrate-electrolyte feedings improve1 h time trial cycling performance. Int J Sports Med 18:125-129.

Maffucci, D. M., and R. G. McMurray. 2000. Towards optimizing the timing of the pre-exercise meal. International Journal of Sport Nutrition and Exercise Metabolism 10(2):103-113.

McConell, G., K. Kloot, and M. Hargreaves. 1996. Effect of timing of carbohydrate ingestion on endurance exercise performance. Med Sci Sports Exerc 28:1300-1304.

Moseley L., G. I. Lancaster, and A. E. Jeukendrup. 2003. Effects of timing of pre-exercise ingestion of carbohydrate on subsequent metabolism and cycling performance. European Journal of Applied Physiology. 88:453-458.

Nicholas, C. W., C. Williams, H. K. Lakomy, G. Phillips, and A. Nowitz. 1995. Influence of ingesting a carbohydrate-electrolyte solution on endurance capacity during intermittent, high-intensity shuttle running. J Sports Sci 13:283-290.

Rodriguez, N. R., L. M. Vislocky, and P. C. Gaine. 2007. Dietary protein, endurance, exercise, and human skeletal-muscle protein turnover. Curr Opin Clin Nutr Metab Care 10:40-45.

Rodriquez, N. R., N. M. DiMarco, L. Langley, American Dietetic Association, Dietitians of Canada, & the American College of Sports Medicine. 2009. Nutrition and athletic performance. Journal of the American Dietetic Association. 109(3): 509-527.

Sawka, M. N., L. M. Burke, E. R. Eichner, R. J. Maughan, S. J. Montain, and N. S. Stachenfeld. 2007. American college of sports medicine position stand: Exercise and fluid replacement. Medicine and Science in Sports and Exercise 39:377-390.

Sugiura K., and K. Kobayashi. 1998. Effect of carbohydrate ingestion on sprint performance following continuous and intermittent exercise. Med Sci Sports Exerc 30:1624-1630.

van Loon, L. J. C., T. D. Tipton KD, and L. J. C. van Loon (eds). 2013. Role of dietary protein in post-exercise muscle reconditioning. Nutritional Coaching Strategy to Modulate Training Efficiency. Nestlé Nutr Inst Workshop Ser. Nestec Ltd. Vevey/S. Karger AG Basel 75:73-83.

Putting Protein in Its Place

newfoodpyramid_largeProtein powders, bars, and drinks are often touted as the key to enhancing muscle growth, increasing energy, and losing excess body fat. Nutrition science indicates that excess protein intake can cause a decrease in the intake of other essential macronutrients. It can also saturate the body’s protein supply and result in depleted calcium stores, adversely affected kidney function, and damage to other critical systems of the body, including the cardiovascular system. Scientists recommend meeting the majority of nutritional needs from a nutrient-rich diet that balances the intake of carbohydrates, fats, and protein.

Learn the basics of how protein affects your performance or read the more technical explanation.

Articles by Jamie Saunders

Putting Protein in its Place (Basic)

newfoodpyramid_largeThe three macronutrients- carbohydrate, protein, and fat- tend to rotate through periods of time in the sports nutrition spotlight. Each of these nutrients performs numerous important functions in the body, and all are required in the diet of athletes. Of these nutrients, protein is often promoted as the most important in relation to athletes’ requirements. In fact, the Greek word proteos, from which the term protein is derived, translates to mean “primary” or “taking first place”.  In order to put protein in its proper place in sports nutrition, a look at the current research and recommendations is needed.

Protein has several important functions in the body, such as transporting nutrients and oxygen in the blood. Protein also plays a role in tissue growth and repair, the immune system, fluid balance, wound healing, and many chemical reactions in the body. These functions are unique to protein. Protein can also provide energy for the body; however the body prefers to use carbohydrates and fat for energy.

Athletes need to consume enough protein to meet their needs. It is recommended that protein provide 10% to 35% of an individual’s total calories. Another form of protein recommendations is based on an individual’s body weight. These recommendations are shown in Table 1, and are usually given in ranges. With each of these ranges, athletes exercising longer and harder should aim for the upper end of the range, while athletes exercising shorter and at lower intensities should aim for the lower end of the range. Table 2 shows appropriate protein requirements per day according to body weight and various protein recommendation levels.

Although many athletes believe they need protein supplements to meet their protein needs, most athletes can get enough protein simply by eating a healthy diet. Foods rich in protein include meat, poultry, fish, dairy products, eggs, beans, nuts, and some grains. Because protein is readily available in many foods, protein powders are generally unnecessary for athletes. Protein bars and protein drinks may be a convenient alternative in certain situations, however obtaining protein from food sources is always the recommended approach.

Many athletes believe they need excess amounts of protein to help them build muscle. In fact, no benefit has been demonstrated for protein intakes above 2.0 grams per kilogram, and there are several possible negative effects to bone, kidney, and cardiovascular health with excess protein intake. Eating extra protein also likely means that the athlete is not getting enough carbohydrates and fat. All three of these nutrients are important for athletes, and all are needed for athletes to perform at their best. If any of the three represent a disproportionately high amount in the body, the athlete may not be getting enough of the other two. Thus, it is in the appropriate balance of the three macronutrients that athletes can maximize their performance.

Table 1. Daily protein recommendations in grams per kilogram body weight by population type.

Population

Protein Recommendations

General Population

0.8 grams per kilogram body weight

Recreational Athlete

0.8-1.0 grams per kilogram body weight

Endurance Athletes

1.2-1.4 grams per kilogram body weight

Ultra-Endurance Athletes

1.2-2.0 grams per kilogram body weight

Strength Athletes

1.2-1.7 grams per kilogram body weight

 

Table 2.  Daily protein recommendations in grams according to body weight and varying protein recommendation levels.

0.8 g/kg

1.0 g/kg

1.2 g/kg

1.4 g/kg

1.6 g/kg

2.0 g/kg

125 lbs.

45 g pro

57 g pro

68 g pro

80 g pro

91 g pro

114 g pro

150 lbs.

55 g pro

68 g pro

82 g pro

96 g pro

109 g pro

136 g pro

175 lbs.

64 g pro

80 g pro

95 g pro

111 g pro

127 g pro

159 g pro

200 lbs.

73 g pro

91 g pro

109 g pro

127 g pro

145 g pro

182 g pro

225 lbs.

82 g pro

102 g pro

123 g pro

143 g pro

164 g pro

205 g pro

Learn more technical details about protein.

By: Jamie Saunders, University of Utah
Jamie Saunders has always been interested in the area of nutrition and wellness. Saunders graduated from Southern Utah University with a Bachelor’s degree in Human Nutrition, and from the University of Utah’s Coordinated Master’s Program in Dietetics, with an emphasis in Sports Dietetics. She is a Registered Dietitian and currently works as the Outpatient Dietitian for the University Health Care’s South Jordan Health Center. 

 

Putting Protein in Its Place (Technical)

The three macronutrients- carbohydrate, protein, and fat- tend to rotate through periods of time in the sports nutrition spotlight. Each of these nutrients performs numerous important functions in the body, and all are required in the diet of athletes. Of these nutrients, protein is often touted as the most important in relation to athletes’ requirements. In fact, the Greek word proteos, from which the term protein is derived, translates to mean “primary” or “taking first place” (Gropper et al. 2008).  In order to put protein in its proper place in sports nutrition, an examination of the current research literature and recommendations is warranted.

The basic units of proteins are amino acids. There are twenty different amino acids, which connect by peptide bonds in varying combinations and lengths, to form polypeptides (Albert et al. 2002). Proteins are organized into primary, secondary, tertiary, and quaternary levels of structure, with each subsequent level becoming more complex in nature. The structure of protein is important because the functional role of protein is determined by its organization and structure (Gropper et al. 2008).

Proteins in the body function as catalysts, enzymes, hormone messengers, and transporters of nutrients and oxygen in the blood (Gropper et al. 2008).Protein is involved in the synthesis, maintenance, growth, and repair of tissue (Zieve et al. 2011). Protein also plays a role in the immune system as it is involved in the formation of enzymes, hormones, and antibodies. Protein can act as a buffer in the body, and it assists in the maintenance of fluid, electrolyte, and acid-base balance. Another function of protein is the role it plays in blood clotting, and therefore wound healing. Lastly, protein plays a role in the provision of energy. More precisely, one gram of protein provides four calories of energy (Gropper et al. 2008).

A review of the listed functions of protein reveals the importance of this macronutrient in the realm of athletics. Another important note is that aside from the function of providing energy, all of the functions discussed are unique to protein, meaning carbohydrates and fat cannot carry out these functions (Gropper et al. 2008). Thus, the necessity of protein is certain; however, it is essential to determine how much of this nutrient is required in order to assure the proper functioning of these roles in the body.

newfoodpyramid_largeThe Recommended Dietary Allowance (RDA) for protein is 0.8 grams of protein per kilogram of body weight, and this recommendation is defined as the average daily amount of protein sufficient to meet the nutrient needs of approximately 97% to 98% of healthy individuals. The Acceptable Macronutrient Distribution Range demonstrates that protein should provide 10% to 35% of total energy (Otten et al. 2006). Both of these recommendations are geared toward the general healthy population, and a topic of popular debate is to what extent athletes require greater than this general recommendation for protein (Fuhrman and Ferrerl 2010).

According to a Joint Position Stand of the American Dietetic Association, Dietitians of Canada, and the American College of Sports Medicine, athletes have varying levels of protein needs depending on the type, duration, and intensity of exercise (Rodriguez et al. 2009). For recreational athletes, protein needs range from 0.8 to 1.0 grams per kilogram body weight per day. For endurance athletes, the recommendation is 1.2 to 1.4 grams per kilogram of body weight, with the needs of ultra endurance athletes ranging from 1.2 to 2.0 grams per kilogram of body weight. Strength athletes require approximately 1.2 to 1.7 grams of protein per kilogram of body weight (Rodriguez et al. 2009). With each of these ranges, athletes participating at higher intensities or longer durations within the particular sport type will have requirements toward the upper end of the range, while athletes performing at lower intensities or shorter durations should meet their protein needs if they follow the recommendations given for the lower end of the range (Dunford and Doyle 2012). Table 1 shows appropriate protein requirements per day according to body weight and various protein recommendation levels.

Table 1. Daily protein recommendations in grams according to body weight and varying protein recommendation levels.

0.8 g/kg

1.0 g/kg

1.2 g/kg

1.4 g/kg

1.6 g/kg

2.0 g/kg

125 lbs.

45 g pro

57 g pro

68 g pro

80 g pro

91 g pro

114 g pro

150 lbs.

55 g pro

68 g pro

82 g pro

96 g pro

109 g pro

136 g pro

175 lbs.

64 g pro

80 g pro

95 g pro

111 g pro

127 g pro

159 g pro

200 lbs.

73 g pro

91 g pro

109 g pro

127 g pro

145 g pro

182 g pro

225 lbs.

82 g pro

102 g pro

123 g pro

143 g pro

164 g pro

205 g pro

 

Numerous research endeavors were examined to determine the protein recommendation ranges for athletes, and these levels of protein intake are thought to allow sufficient protein amounts for the body to perform its essential roles (Otten et al. 2006). The  numerical recommendations must be translated into actual food intake. Protein is found in a wide variety of foods, including both animal and plant sources. Animal sources include meat, poultry, fish, dairy products (milk, yogurt, cheese, etc.), and eggs. Plant sources of protein include beans, lentils, legumes, nuts, nut butters, seeds, some grains, and certain vegetables (Zieve et al. 2011).

Competitive athletes involved in heavy training commonly believe they cannot meet their protein requirements through food sources alone. Such athletes frequently turn to protein supplements, which come in the form of protein powders, protein bars, and protein drink or shake options. Popular protein bars range from approximately 8 to 20 grams of protein per bar, and protein drink or shake products (premixed or powder) range from about 4 to 50 grams of protein per serving (High protein drinks 2009, Protein bars 2009). Such protein levels can easily be met by consuming regular foods, such as meat. One three-ounce serving of beef provides 30 grams of protein, a similar serving of chicken or turkey provides 26 grams of protein, and three ounces of fish provides 20 grams of protein (Dunford and Doyle 2012). In reality, most individuals consume larger portions of meat, poultry, and fish than three ounces, and therefore may easily get double or more the amount of protein listed. Other protein sources such as dairy products and beans typically provide about 8 grams of protein per serving.  Nuts, such as almonds or peanuts, provide 32 to 40 grams of protein per cup (Dunford and Doyle 2012). As is demonstrated by these examples, athletes should generally not have a difficulty meeting their protein needs through food sources alone.

A few exceptions should be noted, such as in the case of athletes who are not consuming sufficient overall calories, and therefore likely have inadequate protein intakes. In certain cases, consuming adequate protein may be a concern for vegetarian or vegan athletes (Association, Dietitians of Canada 2003). However, it is possible to obtain sufficient protein from a plant-based diet. Thus, protein powders are generally unnecessary for athletes (Mahan and Escott-Stump 2008). Protein bars and protein drinks may be a convenient alternative in certain cases of sport nutrition; however, obtaining needed protein from food sources is always the recommended approach.

Most athletes are able to meet their protein requirements quite easily if they are eating sufficient calories. A common notion is the idea that excess amounts of protein must be consumed in order to assist in muscle gains (Maughan and Shirreffs 2012). In fact, no benefit has been demonstrated for protein intakes above 2.0 grams per kilogram body weight, and there are several possible negative effects with excess protein intake. These include a potentially negative effect on calcium stores, bone health, kidney function in individuals with impaired renal function, and cardiovascular health (Frank et al. 2009).

When considering issues related to excess protein, it is illuminating to examine the processes involved in hypertrophy and net protein balance. The process of hypertrophy, or muscle growth, requires a positive net protein balance (NPB). NPB is comprised of muscle protein synthesis and muscle protein breakdown. If the rate of synthesis exceeds that of breakdown, positive NPB will result, thereby leading to hypertrophy (Phillips and van Loon 2011). As protein intake plays a key role in promoting muscle protein synthesis, many athletes erroneously believe that as their protein intake increases, their muscle protein synthesis increases linearly, indefinitely.  This, however, is not the case. Excess protein will not continue to promote protein synthesis, but rather will be used as a substrate for the process of oxidative metabolism (Frank et al. 2009). As was discussed earlier, protein has numerous unique roles. Thus it is advantageous for protein to be used for executing these roles, rather than acting as an energy substrate- a role filled far better by carbohydrates and fat. Along these lines, if protein is in excess, it follows that fat, carbohydrate, or both are consequently lessened in the diet (Gibala 2007). This displacement of other macronutrients by protein points to another concern with excess protein consumption, as fat and carbohydrates fulfill numerous important functions in the body.

Carbohydrates are the preferred energy source for the body, and they are a required energy source for certain tissues such as the brain, white blood cells, and red blood cells (Dunford and Doyle 2012). Carbohydrates also provide numerous essential vitamins and minerals. If sufficient carbohydrates are consumed, they also provide a protein-sparing effect, in that carbohydrates will be used for energy production rather than protein being used for energy through the process of gluconeogenesis (Gropper et al. 2008). The current recommendations for daily carbohydrate intake are 3 to 5 grams of carbohydrate per kilogram body weight for low intensity, skill-based sports and 5 to 7 grams of carbohydrate per kilogram body weight for moderate intensity exercise less than one hour in duration. For moderate to high intensity endurance or stop and go sports lasting one to three hours in duration, 6 to 10 grams per kilogram body weight is recommended. For high intensity endurance events lasting greater than four hours, the recommendation is 8 to 12 grams carbohydrate per kilogram body weight (Rodriguez et al. 2009). Carbohydrates are found in numerous foods, including grains, cereal, pasta, rice, milk, yogurt, fruit, and starchy vegetables (Dunford and Doyle 2012).

Fats, or lipids, are also an important source of energy for the body (Gibala 2007). Fat also provides essential fatty acids, which are omega-three and omega-six fatty acids. These fatty acids are not made by the body and therefore must be obtained through the diet (American Dietetic Association, Dietitians of Canada 2007). Fat is also a source of fat soluble vitamins (vitamins A, D, E, and K), and fat is required for the absorption of these vitamins (Mahan and Escott-Stump 2008). A few other key roles include insulation, protection of vital organs, and shock absorption. There is not a recommendation in grams per kilogram of body weight for fat, as there is for protein and carbohydrate. However, the Acceptable Macronutrient Distribution Range for fat is 20 to 35% of total energy, with suggested recommendation of 10 to 25% for endurance athletes and 15 to 20% for strength athletes (Phillips and van Loon 2011). Although many athletes believe fat should be minimized in the diet, it is not recommended that athletes ever go below 10% of total energy from fat (Rodriguez et al. 2009).

The three macronutrients- protein, fat, and carbohydrate- all play key roles in the body, and all are necessary for promoting optimal athletic performance. Consuming any of these nutrients in excess above the recommended amounts frequently leads to displacement of one or both of the other macronutrients. Though protein does perform numerous essential functions required for physical activity processes, carbohydrates and fat are similarly important for the athlete. Thus, it is in the appropriate balance of the three macronutrients, rather than the disproportionate ranking of one above the others, that athletes can maximize their performance.

By: Jamie Saunders, University of Utah
Jamie Saunders has always been interested in the area of nutrition and wellness. Saunders graduated from Southern Utah University with a Bachelor’s degree in Human Nutrition, and from the University of Utah’s Coordinated Master’s Program in Dietetics, with an emphasis in Sports Dietetics. She is a Registered Dietitian and currently works as the Outpatient Dietitian for the University Health Care’s South Jordan Health Center.

References

Alberts, B., A. Johnson, and J. Lewis, et al. 2002. Molecular biology of the cell 4th edition. Garland Science, New York, NY, USA.

American Dietetic Association, Dietitians of Canada. 2007. Dietary Fatty Acids. Journal of the American Dietetic Association. 107: 1599-1611.

Association, Dietitians of Canada. 2003. Vegetarian diets. Journal of the American Dietetic Association. 103:748-765.

Dunford, M. and J.A. Doyle. 2012. Nutrition for sport and exercise 2nd edition. Wadsworth, Belmont, California, USA.

Frank, H., J. Graf, and U. Amann-Gassner. 2009. Effect of short-term high protein compared with normal-protein diets on renal hemodynamics and associated variables in healthy young men. American Journal of Clinical Nutrition.  90(6):1509-16.

Fuhrman, J., and D.M. Ferrerl. 2010. Fueling the vegetarian (vegan) athlete. Current Sports Medicine Reports. 9(4): 233-241.

Gibala, M.J. 2007. Protein metabolism and endurance exercise. Sports Medicine. 37(4-5): 337-340.

Gropper, S.S., J.L. Smith, and J.L. Groff.  2008. Advanced nutrition and human metabolism 5th edition. Wadsworth, Belmont, California, USA.

High protein drinks. 2009. Retrieved from https://patienteducation.osumc.edu/Documents/high-protein-drinks.pdfAmerican Dietetic

Mahan, L. K., and S. Escott-Stump. 2008. Krause’s food and nutrition therapy 12th edition. Saunders Elsevier, St. Louis, Missouri, USA.

Maughan, R.J., and S.M. Shirreffs. 2012. Nutrition for sports performance: issues and opportunities. Proceedings of the Nutrition Society. 71:112-119.

Otten, J., J. Hellwig, and L. Meyers. 2006. Dietary reference intakes: The essential guide to nutrient requirements. National Academies Press, Washington, DC, USA.

Phillips, S.M., and L.J.C. van Loon. 2011. Dietary protein for athletes: from requirements to optimum adaptation. Journal of Sports Sciences. 29(sup1): S29-S38.

Protein bars. 2009. Retrieved from https://patienteducation.osumc.edu/Documents/protein-bars.pdf

Rodriquez, N.R., N.M DiMarco, and L. Langley. 2009. American Dietetic Association, Dietitians of Canada, and the American College of Sports Medicine. Nutrition and athletic performance. Journal of the American Dietetic Association.  109(3): 509-527.

Zieve, D., D. R. Eltz, and A. Evert. 2011. Protein in the diet. U.S. National Library of Medicine. Retrieved from http://www.nlm.nih.gov/medlineplus/ency/article/002467.htm