Nutrient timing key to sports nutrition

Nutrient timing key to sports nutrition

Nutrient timing, or rather "ingredient timing," is one of the most powerful ways to enhance athletic training and performance. Which ingredients are tops in sports science?  

Hundredths of a second can separate a gold medal winner from someone who doesn’t make it to the Olympic medal stand. Therefore, athletes are looking to gain every performance advantage they can get their hands on. As scientific advances in sports nutrition continue to unfold, specific functional ingredients can help athletes train harder, gain strength, size and speed, and feel better so they perform their best.

The concept of “nutrient timing,” which should more aptly be called “ingredient timing,” continues to prevail as one of the most powerful methods of enhancing training and performance. And, specific ingredients have made their way to the forefront of sports science research.

Here's a look at the top ingredients and the science behind them: carbohydrates, protein and amino acids, caffeine, beta-alanine and creatine.

Top ingredients for nutrient timing in sports nutrition

Carbohydrate forms

Carbohydrates are the primary fuel used during aerobic exercise and perhaps one of the most researched ergogenic aids of modern times. The importance of carbohydrates was highlighted on a football field in the 1960s when scientists at the University of Florida (the Gators) realized their players were running low on energy and needed a quick source of carbohydrates during play. The first true sports drink was developed in response to this realization, to help rapidly refuel and rehydrate these football players. Gatorade use quickly spread to all levels of athletes across all sports.

By the 1980s, endurance athletes started espousing the benefits of carbohydrates and the concept of carbohydrate loading—a method used to saturate one’s stores of carbohydrates in the form of glycogen in muscle tissue. Muscle glycogen stores are limited and once they start to decline, a few hours into exercise, athletic performance suffers. Therefore, providing a steady supply of carbohydrates during performance will help decrease an athlete’s reliance on their limited supply of glycogen.1 Aside from impaired performance, low glycogen levels can lead to muscle protein breakdown and, over the course of time, impaired immune functioning.2

Since the early days of sports nutrition research, our knowledge of carbohydrates has evolved. In recent years the focus has been on the optimal type of carbohydrate given at the right time to improve performance and enhance recovery. For years, sports nutritionists have recommended endurance athletes consume 30-60 grams of carbohydrates per hour during activity.

Though many athletes may need more, carbohydrate oxidation is limited when carbohydrate transporters are saturated. However, each carbohydrate has its own intestinal transporter; therefore, using multiple types of sugar increases the amount of total carbohydrates that can be oxidized and used as fuel.3,4 Using multiple forms of sugar as opposed to just one form can reduce fatigue and improve performance in endurance sports. Therefore sports drinks with a mix of sugars may be beneficial for endurance athletes or other athletes competing for three hours or more.5 Using multiple types of carbohydrates may also decrease the likelihood of digestive distress.

Another factor that leads to digestive distress is the type of carbohydrates used. Sports drinks with large amounts of fructose, galactose and amylose may lead to gastrointestinal distress because these sugars are absorbed more slowly that glucose, sucrose, maltose and maltodextrins.6

In addition to fueling during activity, post-activity fueling to replenish glycogen stores is critical for athletes who train daily and even more critical for those who train twice a day or for hours every day. Products created with maltodextrin, glucose and a patented highly branched, high molecular weight glucose polymer solution were shown to be the best options for glycogen replacement compared to an energy-equivalent drink comprised of monomers and oligomers of glucose and a lower molecular mass.7

Glycogen replenishment isn’t something of which only endurance athletes need to be conscious. Resistance exercise uses muscle glycogen stores. The recreational gym attendee does not need carbohydrates after a resistance training session because he can replace his glycogen over a 24-hour period if he consumes adequate amounts of carbohydrates.

However, Olympians and other high caliber athletes should replace their fuel tank of carbohydrates in the form of glycogen in their muscle tissue within the 30-minute window of opportunity after training or competition when their muscle tissue is most receptive to taking up carbohydrates. In addition, for the athlete who has a difficult time maintaining body weight or needs to gain weight, this is also a good opportunity to get more calories in the form of carbohydrates in the body. 

Various forms of modified waxy maize are also gaining some popularity among athletes, though the research on this category of carbohydrates is lagging behind that of other carbohydrates. One in particular, a hydrothermally processed corn starch, was developed initially by one company for children with glycogen storage disease, though it has been used by some endurance athletes in an attempt to train for longer on less fuel (and therefore fewer calories).

This particular starch went head-to-head with maltodextrin in a study that examined metabolic and hormone responses to a 150-minute bout of cycling. The hydrothermally modified starch blunted the spike in glucose and insulin seen with maltodextrin and also increased the breakdown of fat, suggesting this was an alternate fuel source used during the exercise bout. However, no differences in performance were noted and future research will need to investigate if this form of carbohydrate can keep an athlete adequately fueled during long bouts of exercise while also examining how it affects measures of performance.

Protein and amino acids

Protein is essential for increasing muscle growth and repair while also blunting muscle protein breakdown. Scientists have examined the differences in types of protein and how they affect muscle growth, recovery and repair. The milk proteins whey and casein have dominated the protein market.

Though studies that have examined the effects of whey vs. soy have shown that whey has a significantly greater impact on muscle protein synthesis compared to soy.8 In addition, whey is a fast protein—meaning that the amino acids are quickly released into the bloodstream whereas soy is considered intermediate and casein slow because it coagulates in the stomach, slowing down the release of amino acids into the bloodstream. Emerging research is looking at combinations of these proteins for maximum stimulation of muscle protein synthesis due to their varying effects on the rise of amino acids in the bloodstream.

Various amounts of protein have been used in research settings, though a minimum of 25 grams of whey is suggested to maximally stimulate muscle protein synthesis. However, more may be necessary for some athletes depending on their training and food intake or the type of protein they choose post-exercise. Some have theorized in the past that the addition of high glycemic carbohydrates to protein will augment gains in muscle due to the effect these carbohydrates have on insulin levels. However, more recent research has shown that carbohydrates do not further stimulate muscle protein synthesis compared to protein alone if post-exercise protein intake is adequate.9,10 Despite the fact that carbohydrates may not further augment gains in muscle over time when used immediately after resistance training, the addition of carbohydrates is important for athletes who have back-to-back training sessions or train several hours in a day.

While the addition of carbohydrates to protein may not stimulate muscle growth to a greater extent than protein alone, protein may help carbohydrates by further enhancing muscle glycogen replenishment. Therefore, the ideal post-exercise sports nutrition product for an endurance athlete or an athlete who trains more than once per day or for several hours in a day combines carbohydrate with protein.11

Utilizing protein to augment muscle gains in response to resistance exercise is a well-accepted practice. However, for the first time ever, more recent research has shown that protein can also be used during repeated sprints to promote muscle protein synthesis. In one study, a mix containing 24 grams of whey, 4.8 grams of leucine and 50 grams of maltodextrin or a placebo was given to young males prior to a repeated sprint cycling session. The increase in anabolic signaling and muscle myofibrillar protein synthesis following the exercise indicates that this nutrient combination facilitates muscle protein synthesis during anaerobic exercise.12

While protein is most commonly used, there is also a role for the essential amino acids (EAAs). Branched chain amino acids (leucine, valine and isoleucine, which are part of the essential amino acids) when taken prior to resistance training increase muscle protein growth. Leucine in particular has an important role stimulating specific pathways underlying muscle protein synthesis.

In addition to the role the essential amino acids (EAAs) play in gaining strength, they can also be used during long duration endurance training or competition to help repair muscle tissue and attenuate the soreness and inflammation brought on by muscle breakdown during activity or used after activity to improve muscle protein growth during the recovery period.13 And finally, the EAAs can decrease muscle protein breakdown due to weight loss from the demands of endurance activity.

Caffeine, beta-alanine, creatine


Caffeine is one of the oldest performance-enhancing aids around. As a central nervous system stimulant it temporarily increases alertness, decreases fatigue and improves mental functioning.14 In addition, caffeine effectively enhances sports performance including maximal endurance exercise and high intensity exercise, when consumed in doses ranging from 3-6 mg per kilogram bodyweight. Like many ingredients, more isn’t better and higher doses of caffeine will not lead to greater performance enhancement. Despite its reputation, caffeine does not negatively affect fluid balance or lead to dehydration. Therefore this ergogenic aid can be used in both training and performance to keep an athlete’s head in the game while also providing a boost in performance.15


Beta-alanine is a relatively newer ingredient that is used to buffer fatigue. For decades athletes were fed information about lactic acid as the cause of all muscle fatigue and soreness. However, lactic acid isn’t the problem. Instead, the build-up of hydrogen ions and drop in muscular pH that occurs due to intense exercise is thought to be one of the main causes of fatigue. But the body produces a substance called carnosine that helps decrease or mitigate this type of fatigue by buffering the acidity produced by hydrogen ion accumulation. Though it may make sense, in theory, to consume carnosine to increase the body’s buffer system, supplemental carnosine cannot be taken up into the muscle intact and instead is broken down once it enters the digestive system. However, carnosine synthesis is limited without sufficient beta-alanine, the rate-limiting substrate in the synthesis of carnosine. Beta-alanine is not an instant fix, though. It takes 4-6 weeks for beta-alanine to increase intramuscular carnosine levels.

Delaying acid production helps delay muscular fatigue allowing you to train at a higher intensity while also improving recovery. Studies show that supplementation with beta-alanine can decrease neuromuscular fatigue during submaximal cycling and increase time to exhaustion.


Aside from protein and total calorie intake, creatine is the next most effective supplement that can be used, in combination with an effective training program, to build muscle tissue. In addition, creatine is the single most effective ingredient for helping athletes gain lean body mass, strength, explosive power and improving sprint performance. Long-term (6-8 weeks) creatine supplementation combined with strength training increases lean body mass by about 7 pounds. 

Though anecdotal reports suggested that creatine causes dehydration, this has never been proven in any clinical trials. In addition, creatine monohydrate has been found to be safe across a wide range of study subjects. It increases total body water and extracellular water and therefore may help regulate body temperature, reduce sweat rate, exercising heart rate (so that the heart isn’t working so hard in the heat) and maintain red blood cells per volume of blood (important for altitude).16,17

Sports nutrition is evolving and providing athletes with legal, effective methods for enhancing training and performance. The difference between winning and losing at the elite level is very small, so every edge an athlete can get could be critical to success. 

Select Suppliers: Sports Nutrition

Albion, Human Nutrition Division
Offers Creatine MagnaPower (magnesium creatine chelate).

Algatechnologies, Ltd.
AstaPure natural astaxanthin from algae; provides antioxidant protection.

Bergstrom Nutrition
Offers OptiMSM, a branded form of MSM. Effective in increasing joint comfort and supporting a normal range of motion.

Bioenergy Life Science, Inc.
Bioenergy Ribose accentuates the body’s natural process of energy synthesis. Suitable for beverages, supplements and foods.

Wellmune WGP
Clinical research indicates that Wellmune WGP may enable recreational and elite athletes to exercise longer and harder with less risk of immune system suppression that normally occurs following high intensity exercise. For supplements, chews, bars, cookies.

Biotropics Malaysia
Supplies PHYSTA, a patented water extraction of Tongkat Ali, a traditional Asian herb used to boost energy and vigor.

Chemi Nutra
Supplies SerinAid PhosphatidylSerine (PS) and AlphaSize Alpha-Glyceryl Phosphoryl Choline (A-GPC). Both are suitable for supplements and fuctional foods and beverages.. SerinAid has a patented effect on maintaining health testosterone levels.

DSM Nutritional Products
Features PeptoPro, a water-soluble casein hydrolysate, high in di- and tri-peptides backed by seven published human studies showing benefits in performance, endurance and muscle recovery.

Fonterra USA, Inc.
Supplies Clear Protein-brand whey proteins, formulated for RTD sports nutrition beverages. Also features Power Protein-brand dairy proteins, formulated to avoid hardness and chewiness in high-protein bars and snacks.

Gencor Nutrients, Inc.
Offers TESTOFEN, a branded Fenugreek extract said to naturally boost testosterone levels.

Humanetics Corporation
Supplies 7-Keto, a naturally occurring substance in the body that declines with age.  Supplementing with 7-Keto can boost metabolism and accelerate weight loss.

Improve USA, Inc.
Offers Aloe Vera gel and whole leaf decolorized.

InterHealth Nutraceuticals, Inc.
Supplies ZMA, a branded formula containing zinc mono-L-methionine sulfate (L-OptiZinc®), zinc aspartate, magnesium aspartate and vitamin B6. Supports healthy testosterone levels as well as muscle strength and muscle power.

Kyowa Hakko USA
Supplies Sustamine, a dipetide form of L-Glutamine and L-Alanine to support muscles.  Also features Cognizin, a branded form of citicholine that can improve mental focus during athletic events.

Lonza Inc.
Offers Carnipure, a branded form of L-carnitine, critical for fat and energy metabolism, as it transports long-chain fatty acids, the key source for energy, to the mitochondria.

ViNitrox, nitric oxide enhancer that boosts circulation. Can be used in gels, capsules, tablets and beverages.

Nutratech, Inc.
Advantra Z, a branded bitter orange extract, boosts the body’s metabolism, increasing fat loss.

OmniActive Health Technologies
Capsimax Capsicum Extract uses a proprietary beadlet technology that delivers the thermogenic power of red hot peppers without the burn.

Roquette America Inc.
NUTRALYS pea protein. Suitable for protein powders and high-protein bars.

Sabinsa Corp.
Supplies GarCitrin, a proprietary extract of Gargincia cambogia, which offers cardiovascular and metabolic benefits.

Scientific Food Solutions
AquaLyte, a Novel alkalizing hydration system with zero calories, and fortified with minerals and electrolytes. For hydration beverages.

Terry Laboratories
Supplies pure Aloe Vera in gel, concentrate and powdered forms. Also supplies whole leaf powders and organic forms.

Trace Minerals Research
ConcenTrace Ionic Trace Mineral Blend for hydration beverages.

TSI Health Sciences, Inc.
Offers PEAK ATP, the exact molecule the body needs for energy synthesis.


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2 Hargreaves M. Muscle glycogen and metabolic regulation.  Proceedings of the Nutrition Society 2004;63(2): 217-20.

3 Jeukendrup AE, Jentjens R. Oxidation of carbohydrate feedings during prolonged exercise: current thoughts, guidelines and directions for future research. Sports Med 2000;29(6):407-24.

4 Jentjens RL, Achten J, Jeukendrup AE. High oxidation rates from combined carbohydrates ingested during exercise. Med Sci Sports Exerc 2004;36(9):1551-8.

5 Jeukendrop, AE.  Carbohydrate and exercise performance: the role of multiple transportable carbohydrates. Curr Opin Clin Nutr Metab Care 2010;13(4):452-7.

6 Fujisawa T, Mulligan K, Wada L, Schumacher L, Riby J, Kretchmer N. The effect of exercise on fructose absorption. Am J Clin Nutr 1993;58(1):75-9.

7 Piehl Aulin KP, Soderlund K, Hultman E. Muscle glycogen resynthesis rate in humans after supplementation of drinks containing carbohydrate with low and high molecular masses. Eur J Appl Physiol 2000;81:346-51.

8 Phillips SM, Tang JE, Moore DR. The role of milk- and soy-based protein in support of muscle protein synthesis and muscle protein accretion in young and elderly persons. J Am Coll Nutr 2009;28:343-54.

9 Koopman R, Beelen M, Stellingwerff T et al. Coingestion of carbohydrate with protein does not further augment postexercise muscle protein synthesis. Am J Physiol Endocrinol Metab 2007;293:E833-E842.

10 Miller S, Tipton K, Chinkes D. Independent and Combined Effects of Amino Acids and Glucose after Resistance Exercise. Med Sci Sports Exerc 2003;35:691-700.

11 Howarth KR, Moreau NA, Phillips SM, Gibala MJ. Coingestion of protein with carbohydrate during recovery from endurance exercise stimulates skeletal muscle protein synthesis in humans. J Appl Physiol 2009;106:1394-1402.

12 Coffey VG, Moore DR, Burd NA, Rerecich T, Stellingwerff T, Garnham AP, Phillips SM, Hawley JA. Nutrient provision increases signaling and protein synthesis in human skeletal muscle after repeated sprints. Eur J Appl Physiol 2011;111:1473-1483.

13 Pasiakos SM, McClung HL, McClung JP et al. Leucine-enriched essential amino acids supplementation during moderate steady state exercise enhances postexercise muscle protein synthesis. Am J Clin Nutr 2011;94:809-818.

14 Brice CF,  et al. Effects of caffeine on mood and performance: a study of realistic consumption. Psychopharmacology 2002;164(2):188–92.

15 Goldstein ER, Ziegenfuss T, Kalman D et al. International society of sports nutrition position stand: caffeine and performance. JISSN 2010;7:5.

16 Greenwood M, Kalman DS, Antonio J, ed. 2008. Nutritional supplements in sports and exercise. New York, NY: Humana Press.

17 Greenwood M, Farris J, Kreider R et al. Creatine supplementation patterns and perceived effects in select division I collegiate athletes. Clinical Journal of Sport Medicine 2000;10(3): 191-4.

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