If you're reading this blog, you're probably sick and tired of hearing so many different opinions on what an optimal post-workout meal should look like. In this post, I'll give a simple rundown of what goes on in the body during/after a workout and how we as nutritionally contentious CrossFitters can respond to what our body needs in the 30-60 min time frame following a workout. This post includes information from Jim Stoppani, an avid powerlifter and Ph.D, as well as the British Journal of Sports Medicine on their study of post-exercise anabolism and the search for the optimal recovery drink.
During a workout, the body calls on blood sugar, muscle glycogen and ATP for the energy it needs during a workout. The body only has small storages of glycogen and ATP, and thus the body calls on more oxygen to create additional ATP for energy. If not enough oxygen is available, lactic acid will form, and while it can be used as an energy source, lactic acid is attributed to post-workout muscle soreness. Lastly, during a workout, tiny tears form in the muscles that help them grow bigger and stronger as they heal. A healthy and nutritious post workout meal can help the body heal and recover, and while muscle soreness is the indication that muscles are changing, eating protein and carbohydrates can help reduce said soreness.
Lactic acid typically leaves the system within 30-60 minutes after a workout, and in order to help repair the tiny tears in the muscles, avoid muscle breakdown and replenish energy storage's in the body to regulate insulin levels, a nutritious meal should be consumed within that exact time frame.
There are a couple components to a healthy and effective post workout meal:
I will go over the importance of each below:
When you train, your body burns glycogen, or sugar. Both blood sugar and muscle glycogen are consumed by your body during a workout, and to recover, as well as progress, you need to restore depleted glycogen levels as quickly as possible. However, not all sugars are created equal. Of the 4 types of sugars out there (fructose, dextrose, lactose and sucrose), you want a sugar that is quickly converted, and will make it to your muscles as fast as possible to speed you on your way to recovery. Fructose can be considered fruit sugar; dextrose comes from wheat, potato or corn starches; lactose comes from milk; sucrose is table sugar. According the the glycemic index that is scored out of 100, dextrose converts to glycogen the quickest (score of 100), followed by sucrose (65), lactose (46) and then fructose (20). It seems appropriate, therefore, that consuming foods with dextrose prior to a workout would make for the most efficient and effective recovery. Ruling out all fruits because they contain a low glycemic index is poor logic, since not all fruits only contain fructose sugars. For example, dried apricots and plums have 9 grams of dextrose and 3 grams of fructose in one serving. One cup of cranberry juice cocktail has 17 grams of dextrose to 12 grams of fructose. Medjool dates have equal amounts of dextrose and fructose, as does pomegranate juice. Read labels of your favorite foods, most natural, healthy and "whole" foods have a combination of dextrose and fructose. Carbohydrates in addition to sugar (since sugar is a carbohydrate) are important to restore blood and muscle glycogen levels. Carbs serve as the key to the door that allows protein and amino acids to absorb into your muscles. Consuming carbs (including sugar) spikes insulin levels which signals muscle cells in the body to open up, thus allowing glucose and protein to enter the muscles.
After a workout, you have successfully broken down muscle tissue which is in need of repair, this is the ideal time for both protein and carbohydrates. Lean proteins such as certain fish, shrimp, chicken, turkey or even whey protein are all excellent sources of protein following a workout. Since protein (amino acids) is the main element of what builds and sustains muscle, it is critical to consume after a workout to ensure that your workout was worth the while.
Insulin and Fat
If this information has caused you to believe that eating a donut after a workout is going to benefit you, you are sorely wrong. A momentary spike in one's insulin post workout through sugars/carbs will indeed allow protein to absorb quicker into the muscles for synthesis. However, once insulin has been released from the pancreas, it signals the body that it has just been fed. Since the human body is always trying to spare energy, this signal halts the body from burning the stored fat and instead turns to the nutrients that have just been ingested. If the food you have just ingested is high in saturated or trans fats (monounsaturated and polyunsaturated fats are good in moderation), the body will simply store those fats for later use and will break down whatever takes less energy to convert to nutrients (the carbohydrates and proteins). Thus, More fat is stored, less is burned. So while sugars are meant to be replenished in your system and will allow for protein to better absorb into your muscles to repair and build, there are still healthy and unhealthy manifestations of sugars to choose from. Like I said above, dextrose (the highest converting sugar) can be found in healthy foods such as whole wheat grains, sweet potatoes (for you paleo-folk), quinoa, and most chocolate protein powders have maltodextrin which converts even faster than dextrose.
In short, eat a quickly digesting carb source 15-20 min prior to exercise and within an hour post-exercise. The post exercise meal should include a ratio of carb to protein right around 4 to 1. Keep your post workout meal low in fat and enjoy the benefits of fueling your body intelligently!