The Metabolic Window

Forgetting to bring a post-workout protein shake gives many regular gym goers the fear. For some, it’s almost as if all the hard work they’ve just completed in the gym has gone to waste because they haven’t taken their post workout shake or left their chicken in the fridge.

Is there any truth to this?

You may have heard individuals refer to the “metabolic window” which I like to refer to as the magical window of gains. Let’s have a look at this magical window of gains, it’s validity and its significance to your training…

The Metabolic Window

The metabolic window is typically described as a 30-minute period, post-exercise, where nutrition influences the body to move from being catabolic to becoming anabolic. Many argue that it is important to consume both protein and carbohydrates immediately after exercise in order to facilitate growth in muscle mass.

During training, the muscle fibres experience micro-tears and in order to repair, they require protein. The muscles are repaired and strengthened through a process known as muscle protein synthesis. Additionally, after exercise, there will be a need for glucose uptake to increase in order to replace energy expended during exercise.  It is hypothesised that during the window your body is in a primed state to receive nutrients (specifically protein and carbohydrates) and therefore consuming an adequate amount of them can help replenish energy stores more efficiently, increase muscle protein synthesis and consequently increase muscular growth.

Ensure you read the key terms below if the you didn’t understand all in the above paragraph.

Key Terms:

Metabolism –  numerous chemical reactions within the body to sustain the living state of cells.

Catabolism – a destructive process where molecules are broken down into smaller units.

Anabolism – the opposite of catabolism. A building process where molecules are formed, constructed by smaller units.

What does Science say?

A recent study “The effect of protein timing on muscle strength and hypertrophy: a metaanalysis” (Schoenfeld et al., 2013), reviews 23 scientific studies that assess the relationship between protein timing and muscular growth. The study is known as a meta-analysis which combines the results of numerous scientific studies to come to an overall conclusion on a specific topic which helps to improve the validity and reliability of the results.

Having reviewed these studies, the results seemed to indicate that consuming protein within the metabolic window did not have a significant impact on muscular adaptations and therefore is not critical as many believe. The study came to the conclusion that overall protein intake throughout the day was of more importance than the timing of the protein consumption.

This table should give you an idea of the amount of protein that you should be consuming per day based on your goals / current exercise:

Protein Requirements1

Don’t worry if you forget to take your protein shake with you to the gym, it’s not going to hinder your progress – timing is not hugely important. However., what will hinder your progress is an inadequate consumption of protein throughout the day and therefore it’s important to ensure you’re consuming the right amount for your goals.

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