What is workout and post-workout nutrition?
Workout nutrition research has been an intriguing topic lately and rightfully so. Numerous studies have taken place examining everything from the composition of the carbohydrate, to the exact amino acid combination. And newer studies continue to reveal effective workout nutrition strategies for athletes and recreational exercisers of all types.
When looking at the broad topic of “workout nutrition,” one has to understand what the ultimate goal is. Athletes/exercisers are typically trying to accomplish three things:
1) Glycogen replenishment
2) A decrease in protein breakdown
3) An increase in protein synthesis
In other words, they want to replenish their energy stores and increase muscle size and/or muscle quality. And in doing so, they want to increase performance and/or improve their appearance.
Proposed Benefits of Workout Nutrition
Why are workout and post-workout nutrition so important?
Muscle protein synthesis is increased (or unchanged) after resistance workouts, but not as much as protein breakdown. The relationship between these two parameters (rate of muscle protein synthesis and muscle protein breakdown) represents the metabolic basis for muscle growth.
Muscle hypertrophy occurs when a positive protein balance can be established during recovery. This is especially difficult with endurance athletes as protein synthesis drops and protein breakdown goes up (Ivy 1977).
However, studies show that this trend can be reversed – specifically, protein synthesis is stimulated and protein breakdown is suppressed when you consume the right type of nutrients right after exercise (Volek 2001; Essen-Gustavsson & Tesch 1990; Robergs et al 1991; MacDougall et al 1988; Tesch et al 1986).
Protein is not the only concern, however. During exercise sessions, stored carbohydrates can be substantially depleted (Volek 2001; Essen-Gustavsson & Tesch 1990; Robergs et al 1991; MacDougall et al 1988; Tesch et al 1986).
So, in the end, the raw materials we give our body through the consumption of food/supplements in the workout and post-workout periods are critical to creating the metabolic environment we desire.
What you should know!
A main factor that can influence the amino acid/glucose delivery and transport is availability. The blood flow to skeletal muscle during and after exercise is greatly increased. Therefore, by providing an amino acid and glucose packed blood supply during and after exercise, the rate of protein synthesis goes up (Pitkanen et al 2003).
Some refer to this workout and post-workout phenomenon as “the window of opportunity”. During this window, your muscles are primed to accept nutrients that can stimulate muscle repair, muscle growth, and muscle strength. Feed your body properly while this window is open and you’ll obtain the benefits. If post exercise nutrient ingestion is inadequate or delayed by as little as 2 hours, a decrease in muscle glycogen storage and protein synthesis is expected (Ivy et al 1988).
To take advantage of this window, you could certainly eat a whole food meal directly after exercise. However, as whole food is slower digesting, you might want to consider recovery drink/bars that contais rapidly digesting carbohydrates (e.g., maltodextrin, dextrose, glucose, etc) and proteins (e.g., protein hydrolysates or isolates).
Consuming nutrients especially in liquid form can result in rapid digestion and absorption (Jentjens & Jeukendrup 2003), plus, liquids are usually tolerated better during/workouts.
For extra credit
The combination of carbohydrate and amino acids during/after exercise results in a stimulatory effect of growth hormone and testosterone (Chandler et al 1994) that isn’t seen during the rest of the day.
When choosing carbohydrates, keep in mind that glucose is absorbed faster than fructose, and solutions high in fructose have been linked to gastrointestinal distress, greater fatigue, and higher cortisol levels (Cori 1925; Berning 1998).
Summary and Recommendations
As a baseline, start by ingesting 30g carbohydrate and 15g protein (in 500ml water) per hour of workout time. This means if you’re working out for one total hour, you’re sipping your 30g carbohydrate and 15g protein drink during that hour. And if you’re working out for two hours, you’re sipping your first 30g carbohydrate and 15g protein drink during the first hour and your second 30g carbohydrate and 15g protein drink during the second hour. Once your workout is done, have a whole food meal within an hour or two of the workout.