What’s your favorite way to fuel up before a workout and refuel afterward? Hopefully, you include a source of protein. Most dietitians recommend eating a snack that includes protein and carbohydrates before and after a workout. You need carbohydrates as they are the main source of fuel that your muscles use during vigorous exercise. Your body can also tap into fat as a primary fuel source, but during high-intensity exercise, your muscles crave carbohydrates, the main fuel source during periods of strenuous activity.
In fact, your body doesn’t use protein as a significant fuel source except during starvation and times of extreme stress. If you’re healthy, consuming enough calories, and not taking part in a prolonged fast, your body only uses about 5% protein for fuel during exercise. However, stress can boost protein breakdown. For example, if you exercised for a long period in a fasted state, your muscles would use protein as an alternative fuel source as your glycogen stores would be depleted and your cortisol level would be higher in response to an exhaustive workout during a fasted state. Cortisol stimulates muscle breakdown, and that’s not what you want if you’re trying to get a lean, strong physique.
Why Your Pre-Workout and Post-Workout Snack Should Include Protein
After a strength-training session or a high-intensity interval workout, your muscles must repair the damage they sustained during exercise. During training, muscle fibers sustain microscopic tears that must be mended. It’s also during repair that your muscle fibers increase in size. For repair and growth to occur, your muscle fibers need access to amino acids. Without them, muscle protein synthesis won’t be as efficient.
In addition, studies show that consuming protein from a dairy source after eccentric resistance reduces the loss of strength that happens 24-72 hours occurs in response to an exhausting workout. Athletes who consume enough protein perform better if they have to work out again before their muscles have fully recovered. The question is whether you need protein right after a workout or if you can wait several hours to have a protein snack. We’ll take a closer look at that shortly.
Can Protein Boost Muscle Performance?
You might wonder whether consuming protein prior to a workout can help muscle performance or boost strength gains. In one study, researchers gave volunteers 25 grams of whey protein before a resistance workout. In another situation, they gave participants a similar protein snack 3 hours after a resistance training session after the subjects had fasted for 3 hours. When they measured one-rep max for bench press and back squat, there were no differences between the groups in terms of one-rep max or body composition.
What do these results suggest? Based on this study, it doesn’t matter when you consume protein, pre-workout or post-workout. What counts is that you consume enough dietary protein to support muscle repair and growth. Other research also suggests that when you consume protein is less important than whether you consume enough. Training matters too. If you want maximum muscle growth and strength gains, use progressive overload.
Whether consuming protein before or after a workout improves muscle performance may depend on a variety of factors. For example, the intensity of the workout, how trained the individual is, the type of protein, and how much total protein a person consumes. So, it isn’t a closed case. We need more research to draw conclusions.
What about The Timing of Protein Intake?
Some studies call into question whether the timing of protein intake matters, the idea that we need to get a carbohydrate/protein snack within a window period after exercise to maximize muscle protein synthesis. Some trainers cite 30 minutes as the window during which we should consume protein to maximize muscle protein synthesis. However, more recent research suggests the “anabolic window,” if one exists is longer, at least several hours after a workout. Most of the evidence showing a window is narrower comes from studies on people who trained in a fasted state. If you consume protein prior to a workout, consuming it after doesn’t boost muscle protein synthesis further.
Carbohydrates Matter Too
After a workout, you need carbohydrates to replenish glycogen stores since your muscles use glycogen as a fuel source during exercise. A carbohydrate snack also helps reduce muscle breakdown after a workout because of its protein-sparing effect. Plus, eating a snack that includes carbs helps reduce the body’s stress response and lower cortisol. Most sports nutrition experts recommend eating a post-workout snack that contains a ratio of three parts carbohydrate to one-part protein.
Protein Intake and Endurance Exercise
Some studies suggest that consuming whey protein before an endurance workout may boost performance but not enough to be clinically significant. As long as you consume enough carbohydrates to fuel exercise and optimize performance, adding an additional dose of protein may not offer added performance benefits. However, some research suggests that it could delay the onset of fatigue and it also helps maintain positive nitrogen balance. Some research also suggests that supplementing with whey protein during preparation for a marathon and during post-marathon recovery reduces markers of muscle damage. In one study, biomarkers of muscle damage were reduced in marathon runners who supplemented with whey protein.
Yet there is another reason to get protein after a long endurance exercise. Prolonged endurance training can suppress immune function on a short-term basis and increase the risk of upper respiratory infections. Consuming a protein snack, along with carbohydrates, after a workout helps reduce immune suppression after an exhaustive workout.
The Bottom Line
Make sure you’re getting enough total protein in your diet. Also, have a pre- and post-workout snack that contains protein and carbohydrates. It’s questionable whether consuming protein before and after a workout will improve muscle strength, body composition, or enhance endurance exercise performance if you’re taking in enough total protein. Still, a protein meal helps maintain positive nitrogen balance and reduces the negative impact of intense training on your immune system. So, enjoy that pre- and post-workout snack!
- Effects of Protein Supplementation on Performance and Recovery in Resistance and Endurance Training. Harry P. Cintineo, Michelle A. Arent, […], and Shawn M. Arent.
- Aragon AA, Schoenfeld BJ. Nutrient timing revisited: is there a post-exercise anabolic window?. J Int Soc Sports Nutr. 2013;10(1):5. Published 2013 Jan 29. doi:10.1186/1550-2783-10-5.