Pre/Post Workout
Pre Workout
Pre-workout meals are to provide alternative energy to preserve energy stores (muscle), and take advantage of increased blood flow to muscle tissue.
Carbohydrates
Consuming simple sugars right before training can reduce the amount of glycogen used during exercise. This can prolong performance.
More importantly, higher blood sugar and insulin levels (from simple carbohydrates) appear to create a hormonal balance that favors’ growth.
Glycogen is the sugar stored in the liver and muscles. Because exercise burns energy at such a high rate, the body is unable to supply sufficient oxygen to be able to use fat for fuel. Instead, it must use sugar both stored in the muscle and brought in from the blood.
Protein
Because the availability of amino acids is often the limiting factor for protein synthesis, a pre-workout protein meal will enhance the delivery of amino acids to muscle tissue. Research has demonstrated the effectiveness of a pre-workout protein drink. This will take advantage of the increased blood flow to muscle during exercise.
Delivery of amino acids has been shown to be significantly greater during the exercise bout when consumed pre-workout than after exercise (Tipton, 2001). Net amino acid uptake across the muscle is twice as high with a pre-workout protein drink as compared to consuming it after.
Post Workout
The food that you eat after training affects the hormonal balance in your body. With the rapid introduction of carbohydrate, protein, and fat post exercise, the body is able to begin repairing damaged tissue and replenish fuel reserves.
Carbohydrates
Carbohydrates are important for performance and perhaps more importantly for glycogen recovery. After a meal, muscle cells transport glucose across the cell membrane in response to the hormone insulin. Insulin binds with its receptors at the cell surface causing a cascade of events that ends with proteins, called glucose transporters, being translocated to the cell surface. Once at the cell surface, these glucose transporters allow glucose to pass through the membrane where they can be phosphorylated and eventually stored as glycogen.
If carbohydrates are lacking in the diet, exercise will cause a glucose deficit and glycogen stores will continue to fall without being replenished to pre exercise levels.
Simple vs. Complex
Studies have shown no difference between different types of carbohydrates eaten post exercise and the rate of glycogen replenishment as long as sufficient quantities of carbohydrate are consumed (Burke 1997).
Over a 24-hour period it is the total amount of carbohydrate consumed that is important.
These processes are influenced by the extent to which glycogen was depleted during exercise as well as the amount of carbohydrate and fat consistently included in the diet, not just a single post workout meal.
Recommendation:
It is recommended that at least 0.7 – 1.0 gram of carbohydrate per kilogram body weight be consumed immediately after exercise.
Try to aim for around 7-10 grams of carbohydrate per kilogram of body weight over a 24-hour period for maximum glycogen storage.
Protein
Without protein, which supplies essential amino acids for growth, the body’s ability to adapt to exercise is greatly diminished.
Protein provides amino acids that are used to rebuild damaged tissues as well as provide enzymes and carrier proteins necessary for adaptation to exercise.
Recommendations:
Current recommendations for total protein intake for athletes is between 1.6-1.8 grams per kilogram body weight, depending on who you read, however, it is not uncommon for bodybuilders to consume in excess of 2 grams per kg of body weight with no ill effects. It should be remembered that the body does not have the capacity to effectively store amino acids. Protein should be eaten at least every 3-4 hours. The evening meal should contain slowly digesting protein that will allow a steady release of amino acids into your system well into the night.
Fat
Eating them immediately after training and at no other time will most likely not have any dramatic effect.
Taken together, research is still lacking where the optimal levels and composition of post-exercise fats are concerned.
Fluids
Hydration is extremely important on the cellular level. Muscle growth is inhibited by dehydration. The rate at which you become dehydrated from training depends on how much you sweat (Gisolfi 1990).
Some people sweat a lot when lifting and others don’t sweat a drop. A good rule of thumb is to drink 1 ml for every calorie that you need. So, if you eat 3,500 calories a day, try to drink 3 liters.
Insulin
Insulin (from carbohydrates) as well as amino acids must be present at the same time. So feeding of the carbohydrate meal can elevate blood glucose and elevated insulin levels, carbohydrates alone are not sufficient to allow protein synthesis to begin.
In Summary
The pre-exercise meal should be high in a quickly digestible protein. This will ensure high delivery of amino acids to the muscle tissue. Carbohydrates can also be taken in to minimize glycogen loss and suppress catabolic hormones.
Fat should be avoided pre-exercise unless the exercise is for endurance.
The post exercise meal should consist of carbohydrate, protein and a small amount of essential fats (fish or nuts), in a form that is easily and quickly digestible.
A liquid meal is the most practical method of post-exercise feeding although it is not essential.
