Maximize Your Workout With Protein & Nutrition Timing

Wednesday, October 25, 2006 - 10:55am

By Krista Scott-Dixon, PhD

We all know it’s important to eat well. A good nutrition program keeps us healthy and also helps us perform better during our workouts. For people involved in regular strenuous activities, such as strength training or high-intensity/long duration cardio workouts, nutrition timing is also important. The body has particular nutritional needs before, during, and after an intense workout such as a weight training session.

Nutrition before your workout

Your body needs enough fuel to carry you through the training session. This means that in the hour or two before training, you should consume some carbohydrates together with some protein. This could be anything from a protein shake to a turkey sandwich.

For more information on what your should eat before your exercise see the following article from TheDietChannel: Workout Preps: What To Eat Before You Workout.

Food during your workout

Particularly if the workout is lengthy, you should consume some simple carbohydrates, such as by sipping at a little juice or a sports drink.

Why do you need to eat during the post-workout period

First, a little explanation. Bodies like to be in a state known as homeostasis: nothing changes, everything proceeds nicely, no surprises, keep on keepin’ on. Bodies only adapt if they have to, because they’re thrifty and they don’t like to waste energy. In biological terms, a workout is a stress on the body that makes the body adapt by getting a little bit stronger or fitter. After the workout, the body says, “Okay, that was challenging; I need to find a way to manage that more effectively so that next time it won’t be a problem for me.”

Following a training session, the body is a tiny bit damaged at the cellular level, and this damage isn’t just in the areas that you might have worked that day. The whole system is involved: the hormonal environment, the immune system, the muscle tissue, etc. The body needs to repair this damage in order to get stronger and adapt.

For information on coping with eating late following exercise see the following article from TheDietChannel: Post-workout meal: Appropriate after 8 p.m?

Protein’s role in post-workout muscle repair

Protein is the “building block” for muscle (and amino acids are the building blocks of proteins), and during a workout, it breaks down, a process known as protein degradation. After the workout, in the repair process, it’s built up again, a process known as protein synthesis. This ongoing cycle of building-up/breaking-down, which goes on constantly, is known as protein turnover. The body can’t synthesize protein from nothing; it needs nutrients to do so. Thus, after a training session, you need to make sure that the body has the fuel it requires to do its job.

Here’s where things get interesting. Following a workout, protein synthesis shoots up, and it stays up for at least 24 hours afterwards. This is why trainees are instructed to do two things immediately after a workout (i.e. within the first 45 minutes):

  1. Consume some simple sugary or starchy carbohydrates to make insulin spike, which then shoves nutrients into the cells more effectively.
  2. Consume some protein for immediate delivery to hungry cells.

Tip: To make an easy post-workout protein shake that meets the carbs plus protein requirements, shake some fruit juice up with some soy protein powder in a plastic container.

Additionally, trainees should make sure to consume another meal of carbohydrates and protein (this time consume more complex carbohydrates, such as whole grains) within a couple of hours post-workout.

Leucine: The ideal post-workout protein

But what kind of protein is best? A recently released study (Norton and Layman 2006) came to a provocative conclusion: The amino acid leucine plays a major role in protein synthesis, and in fact, replenishes protein faster than anything else.

Unlike many substances that must go through various processes in the body to “work,” leucine can easily be consumed in the diet. The more you eat, the more leucine is available to the body. Remember that I said protein synthesis continues for at least 24 hours? Well, in Norton and Layman’s study, a complete meal containing protein (or leucine alone) produced complete recovery of muscle protein synthesis within the first hour after exhaustive exercise. Woah!

Sources of leucine

What foods are high in leucine? Glad you asked. According to, some of the foods highest in leucine are:

  • Soy protein (especially soy protein powder)
  • Cottage cheese
  • Fish, particularly tuna and cod
  • Turkey
  • Egg white

Poultry, pork, beef, game meats and shellfish also contain leucine.

For more information on maximizing your performance with the right diet see the following article from TheDietChannel: Sports Nutrition: 8 Nutritious Ways to Maximize Your Workout.


Ivy, John, and Robert Portman (2004). Nutrient Timing: The Future of Sports Nutrition USA: Basic Health Publications.

MacDougall, J.D. et al. (1995). “The Time Course for Elevated Muscle Protein Synthesis Following Heavy Resistance Exercise.” Canadian Journal of Applied Physiology. 20: 480-486. 269:E309-315.

Norton, Layne E. and Layman, Donald K. (2006) “Leucine Regulates Translation Initiation of Protein Synthesis in Skeletal Muscle after Exercise” American Society for Nutrition Journal of Nutrition 136:533S-537S (February).