Nutrient timing for better workout results - the postworkout anabolic window

A workout routine can be tough. Not only because someone is doing a big effort, sweating in the gym or running in a park, but also because of the desired results, which quite often take a lot of time and energy.

The main objective of people who follow a workout routine is to increase muscle mass and/or decrease body fat. This objective does not only come with a strict exercise program, but equally or maybe even more important with a strict diet.


Nutrient timing is a definition that is used for adapting the intake of special nutrients to a workout schedule. The principle of Nutrient timing was first published in the year 2004 by John Ivy and Robert Portman. It was a revolutionary way of explaining the timed intake of different nutrients in accordance to exercise and the related growth of fat free muscle mass.


Since then a lot of research on muscle metabolism has been done and some of the principles couldn’t be replicated while others could.


The strategy is designed to maximize exercise-induced muscular adaptations and facilitate repair of damaged tissue. It seems that these timing strategies can produce dramatic improvements in body composition, particularly with respect to increases in fat-free mass.


A concept that has been extracted from this theory and is repeated as a mantra amongst fitness enthusiasts is the so called “Post workout anabolic window”. What this is, if it works and how you can take advantage of it, will be explained right now.


To start with let us explain the words “anabolic” and “catabolic”:


Anabolism: the synthesis of complex molecules in living organisms from simpler ones together with the storage of energy. In simple words this is when the body builds something up.


Catabolism: the breakdown of complex molecules in living organisms to form simpler ones, together with the release of energy. This is when the body breaks something down.


Anabolism and catabolism is not only referred to protein synthesis, but to all tissue and cells that are built in our body. Today we will have a special look on the anabolism and catabolism of muscle mass.


What exactly is the post workout anabolic window:

During a workout a muscle is generally in a catabolic state. The switch that turns on the anabolic machinery is insulin.


Insulin is a hormone that is highly involved in the carbohydrate metabolism. It is the key for the glucose molecules to leave the bloodstream and enter the muscle cells amongst others.


During a workout the muscle is generally in a catabolic state. To shift from this catabolic to an anabolic state we have to ingest carbohydrates to increase insulin. This can be achieved with carbohydrates, especially with high glycemic carbs or simple sugars. Furthermore it has been found in a scientific work that combining high glycemic carbs with protein is the best way to shift the muscle from a catabolic state to an anabolic one.


The post workout anabolic window is a 45 minute period after working out where the muscle cells are super sensitive to the anabolic effects of insulin. Insulin at this point is able to stimulate protein synthesis aka the development of muscle mass. The sensitivity of the muscle cells to insulin decreases significantly with time and even changes to insulin resistance after 45 minutes.


A study published in 2006 by Cribb and Hayes also showed that protein, carbohydrates, and creatine taken around a training session could lead to more muscle mass and strength gain than those same nutrients eaten further from the session.


So it seems that there is enough evidence to support the importance of taking a protein/carbohydrate mix right after working out or at least in a 45 minutes window. In fact, one study even showed that waiting longer than 45 minutes after exercise for a meal would significantly diminish the benefits of training.


While some time has passed by since nutrient timing was published, we know today that the post workout metabolic window is a bit longer “open”, than initially thought. So you don't have to rush to your protein shake immediately after putting down the barbell. Some more research has shown that the window is about 2 hours.


As usual, as soon as there are theories scientifically proved, investigators start to try to reproduce this theory to back up the conclusions and statements and guess what? They failed. In fact, talking about the post workout metabolic window or the nutrient timing system, there are approximately 7 studies done, all with around 30 trained or untrained people. 4 of are showing that the nutrient timing system works and 3 that it doesn't. As usual here is more evidence needed to know more about this complex topic.


The nutrient timing system, including taking advantage of the post workout metabolic window has helped many people to get really good results. It broke with some really strong beliefs, like the more protein the better, no matter when.


During movement, especially intense ones, like weight training or high intensity resistance training our bodies transform into nutrient-processing powerhouses. During this time our muscles suck in glucose hungrily, either oxidizing it as fuel or more readily storing it as glycogen (instead of fat). And post-workout protein consumption cranks up protein synthesis.


We suggest you to try it, if it works for yourself. No matter in which bootcamp you are, being open to try things and see if they work for you is a good way to find what really works for you. Research gives us a guidelines, but the best research you can do is to try it on your own body.


Muscle metabolism is a complex chemical and physical process. It depends on many factors. It is almost impossible to include all factors that have an impact on muscle metabolism in one scientific work. This is why there are different outcomes. The study designs are always a bit different one from the other.


Bottom line:

The nutrient timing system works for sure. How much in detail depends not only on the external factors but also on every person as we are all different, have different habits and a different gene machinery in our body that plays an important role and that can’t be included in a study.


A really important point are the goals a person has. It is clear that nutrition for a marathon runner, a competing bodybuilder and the typical office guy that hits the gym twice or maybe once a week is totally different.

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