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Fast vs. Slow Protein Absorption and How it Affects Your Body

Fast vs. Slow Protein Absorption and How it Affects Your Body

Looking for a protein powder that’s right for you can be a serious fitness challenge in itself. You want a protein that will help with all aspects of training, including promotion of muscle growth, muscle repair, and prevention of muscle breakdown -- what’s the point on gaining and repairing hard earned muscle if you don’t have anything to help prevent it from breaking down? The solution is all in the protein and its absorption rates!

The Breakdown of Protein

Proteins are composed of 21 amino acids, which are the building blocks for muscles and provide energy to the body.1  Nine of these amino acids are known as ‘essential amino acids’ as our bodies cannot produce them -- we can only get them through the food we consume. The nine essential amino acids include: phenylalanine, leucine, lysine, valine, threonine, methionine, isoleucine, histidine, and tryptophan. All of the essential amino acids are broken down from the protein we eat and then our bodies use all nine for slightly different purposes.2

A ‘complete protein’ contains all nine essential amino acids.1 Several whey and casein proteins will say they are a complete protein, but don’t be fooled! Just because a protein contains the essential amino acids, doesn’t mean your body is getting all of them. The amino acids need to be in proportion similar to what is required by your body, which can be measured by a biological value. A biological value score is based on how well the amino acids are absorbed by the body, with 100 percent being the best and 0 percent being the worst. Therefore, a low percentage means the amino acid did not get absorbed as much as you may have thought it did. It is even possible for an essential amino acid to not be absorbed at all! This is really important to understand because unlike carbohydrates or fats that can be stored in your body, unused protein is excreted if it is not absorbed.1

We have to dig a little deeper and understand that it isn’t about what you are consuming, but what you are absorbing that matters.

Fast vs. Slow Absorption Rates

Protein in liquid form is absorbed faster than protein that is consumed from whole foods.3 When comparing digestion speed in whey and casein protein powders, it is whey that wins the race while casein is digested at a slower rate. Sounds like digesting protein fast is a good thing, right? Let’s take a look...

First we need to understand how protein is metabolized. When we metabolize our food, we use two processes: anabolism and catabolism.4 Anabolism is the process which builds molecules the body needs, and requires energy to do so. Catabolism on the other hand, is the process that breaks down complex molecules into smaller molecules and releases energy for the organism to use and recycle these smaller molecules. When we look at these processes with regard to effects on exercise, it is the anabolic process that builds muscle mass with the energy stored from the catabolic process of breaking down the molecules. The catabolic process also provides the energy to burn fat and calories.4

With whey protein there is a large increase in amino acids that results in rapidly absorbed proteins, the result is an increased amino acid catabolism -- energy.5 This is great when working hard at the gym as a lot of energy is required to exercise.

With casein protein, amino acids are supplied in a more continuous way which does not stimulate amino acid catabolism but does result in protein anabolism.5 This is great for building muscle and preventing muscle breakdown.

Studies have shown it takes whey protein approximately 1.5 hours to pass through the section of the gut that can absorb it.6 The maximum rate whey protein can be absorbed is around 8-10g per hour. That being said, in the 1.5 hours the protein is able to be absorbed, a maximum of 15g is actually taken in, meaning it has a low biological value.

In order to sustain protein synthesis for longer than 1.5 hours, you would need repeated doses of whey protein throughout the day. So anytime you see whey protein that claims to include 50g of protein, note 35g of that precious protein is going down the toilet (literally).6

Casein protein as previously noted, takes longer to absorb allowing for prolonged increase in free amino acids. Therefore, casein protein prevents muscle breakdown, but on the other hand, lacks the initial burst of amino acids required for energy. In contrast, whey protein as previously noted, is absorbed faster allowing for a surge in energy, and muscle growth and repair, but unfortunately, whey protein does not stay in the body long enough to absorb the majority of the serving, which in turn results in muscle breakdown.5

So now we are back at the start -- how do you know which protein is for you?

Plant-Based Protein

It appears the only way to have it all is to take both whey AND casein, right? WRONG!

Let’s talk about plant-based protein.

Many plant-based proteins are free of lactose (found in several casein proteins) and whey (also containing lactose), both of which are very common food allergies/intolerances. If you consume a protein you are allergic or intolerant to, your body will absorb very little of the proteins! To find out more about symptoms of a lactose and whey intolerance or allergy check out The Problems with Whey Protein.

Other plant-based proteins such as pea and brown rice are also found to have slower absorption times. With this in mind, Dr. Robert Pastore, Chief Science Officer, Founder, and CEO of Modus Nutrition created a hypoallergenic, plant-based protein that offers 30g of protein per serving using a blend of pumpkin seed protein, cranberry seed protein, and potato isolate protein.7 Modus is proud to have a bioavailability score of 100 percent (meaning all 30g will be absorbed)!

This special blend includes 7g of instantized branched chain amino acids to spark protein synthesis, 22g of fast-absorbing protein allowing for muscle growth and repair, and 8g of protein with a delayed absorption to prevent muscle catabolism (breakdown) hours after consumption.7

For the first time, Modus Professional Plant-Based Protein breaks the barrier of plant based protein products, and is a true competitor to dairy based protein powders with a higher total essential amino acid content and total protein content per serving.

It is possible to have it all with just one protein -- Modus!


  1. Lose weight & improve your health with a real food diet | Fooducate.!page=post&id=54637528-C22F-288D-4494-86B7BD5B9737. Published November 12, 2014. Accessed October 5, 2018.
  1. Van De Walle G. 5 Proven Benefits of BCAAs (Branched-Chain Amino Acids). Healthline. Published July, 11 2018. Accessed October 5, 2018.
  1. Busch S. How Many Grams of Protein Can Your Body Absorb in One Sitting?. Published October 3, 2017. Accessed October 5, 2018.
  1. Anabolism vs Catabolism - Difference and Comparison | Diffen. Published 2018. Accessed October 6, 2018.
  1. Mosoni L, Mirand P. Type and timing of protein feeding to optimize anabolism. Curr Opin Clin Nutr Metab Care. 2003;6(3):301-306. doi:10.1097/01.mco.0000068961.34812.77
  1. Kollias H. Protein supplements: Is protein absorption the problem? | Precision Nutrition. Precision Nutrition. Published 2018. Accessed October 5, 2018.
  1. Modus Nutrition. What Modus Nutrition Stands For As A Company; 2018. Accessed October 9, 2018.