What to eat before, during, and after a workout is one of the more perplexing issues faced by beginner exercisers, fitness enthusiasts, and athletes alike. Fortunately, this also happens to be the most widely researched topic in sport and exercise nutrition today.
The maturation of sports beverages has been quite dramatic over the past 50 years. Once, drinking water during exercise was thought to be a sign of weakness, as well as something that could actually take away from training adaptations; now water is only one of the numerous components of contemporary sports beverages. Progression has been made from water, to pickle juice (which some might remember was taken in for its sodium content), to Gatorade, and now to the next generation of nutrient timing supplements. The research and its practical implications are relevant to all who are exercising, regardless of training status (beginner to advanced), goals (weight loss to marathoner), or dietary habits (poor to perfect). This article will highlight the objectives of nutrient timing, the mechanisms of its effects, the latest research, and practical recommendations for use.
Nutrient Timing Objectives
The goals of nutrition during and around exercise (of any type or intensity) are threefold:
1. To provide energy (mostly in the form of carbohydrates, although in some cases protein) for the exercising muscle.
2. To prevent the excessive breakdown of muscle proteins.
3. To allow for the synthesis of nutrients (muscle proteins or stored carbohydrates) following exercise.
In order to accomplish these three objectives, nutrients have to be in the correct form (liquid), of the correct composition (whey protein and simple sugars), and dosed at the correct intervals (immediately before, throughout, and immediately after a workout).
The reason the formulation and dosing of the nutrients is so critical around the exercise bout is related to the hormonal and cardiovascular changes that occur during exercise. Essentially, when the body shifts into an exercising state, blood is diverted away from the stomach and small intestines to the active skeletal muscles. This change in blood distribution, coupled with a rise in the fight-or-flight hormone epinephrine, greatly impairs digestion and the ability of the body to uptake ingested nutrients. As such, the nutrients that are ingested have to be in the simplest, most digestible form possible. Hence, the above recommendation of a liquid supplement containing only whey protein (a fast-digesting milk protein derivative) and simple sugars (like sucrose – table sugar – or dextrose). Nutrients in any other form (like solid foods, even protein bars), or comprised of anything else, simply won’t digest during exercise; therefore, they’ll sit in the stomach and wait until long after exercise is completed to be digested and used by the body.
Since the vast majority of blood flow is re-routed to active skeletal muscles during and shortly after exercise, nearly all of the nutrients consumed (that are digested) will go directly to the muscles that desperately need them. This means greater amounts of energy in those muscles for performance during the workout and enhanced recovery and adaptation for those muscles following the workout. Simply put, more energy equates to improved training capacity; that coupled with enhanced recovery and adaptation equals significantly greater results from training.
We can relate the research findings to the three objectives listed above. First and foremost, when researchers look at the energetic effect of these drinks, they measure something called “time to fatigue.” The longer the time to fatigue, the greater the energetic effect of the drink. Researchers found protein-carbohydrate beverages outperform carbohydrate beverages by 125%, and water alone by 200%, in time to fatigue testing. The researchers attribute these differences to protein and carbohydrate working through separate metabolic pathways to provide more energy. When biomarkers of muscle damage are examined, the effect observed is even more dramatic. Research indicates that by adding protein to a carbohydrate-based sports beverage, muscle damage can be reduced by 650%. Less protein breakdown during exercise means easier protein buildup and adaptation post-exercise. Further research indicates significant reductions in 24-hour Cortisol release following consumption of a protein-carbohydrate based beverage compared to a carbohydrate-based beverage. Cortisol is a stress hormone responsible for muscle breakdown and fat preservation; as such, researchers believe that decreasing its production can help to facilitate improvements in body composition.
Practical Implications and Recommendations
The research is clear and definitive. The use of sports beverages containing small amounts of high quality whey protein (6-12g) and fast acting sugars (15-25g) is critical to nearly all training adaptations. The research demonstrates that it is not so much the volume of nutrients that matters, but their quality and timing.
With respect to quality, high-grade whey protein isolates are desirable, as these have greater essential amino acid content (the important portion of the protein that results in adaptation). Sugar quality doesn’t vary so much as it comes in different forms. Research seems to suggest the simpler the sugar, the better, hence, dextrose is the preferable form of sugar.
More important than even the quality of the nutrients is the timing of their ingestion. Consume the nutrients at the right time, and you can see significant adaptation. Do so at the wrong time, and you won’t notice any difference. The data seems to suggest three critical periods – in the following order (and at these specific times): (1) during exercise, (2) post-exercise (within 20 minutes of stopping), and (3) pre-exercise (20-30 minutes before). Ideally, you would consume about 6-12g of protein and 15-25g of sugar at all three intervals (spreading out the during-workout dose for the duration of the workout). However, if you couldn’t spare the calories (due to calorie restriction), you would want to consume the during-workout dose partially during and partially after (within 20 minutes) exercise. In this scenario, you might consume 6g of protein and 15g of carbohydrates during exercise, and the remainder after.
As for purchasing this type of supplement, there are several options from which to choose. Applied Fitness Solutions has private-labeled its own nutrient timing supplement, formulated from the research referenced above. Accelerade, Endurox, and Gatorade G Series Recovery also are products formulated from similar research. You can also make your own mixture of high quality whey protein isolate and dextrose (by buying each separately and combining them), although this is cumbersome.
Take Home Message on Nutrient Timing
When you were told that breakfast is the most important meal of your day, someone lied to you. Research (and a lot of my professional and personal experience) suggests otherwise. Pre-, during-, and post-workout nutrition is the most important meal of your day if you perform any type of exercise, for any goal, at any fitness level. The calories and nutrients you consume in these supplements are the most valuable calories you can consume during your day, period. You owe it to yourself, and the effort you put forth with exercise, to at least try nutrient timing for a month – I guarantee the difference you will you notice with respect to energy, recovery, and adaptation will be so great that you will be hooked forever.