Now before we get into the technical parts of this blog post, I want to make one thing very clear. There is 'optimal' when it comes to any nutrition recommendations. But it is incredibly easy to over-analyse and micro-manage all aspects of our diets.
Ensuring an adequate protein intake is important, but it is simply one part of the bigger picture. We would love for you take this knowledge below, use it to make small improvements to your diet, then rest safe in the knowledge that even if things aren't "perfect" we can still make some great changes and progress.
Right, back to the blog. If you're wondering 'how much protein can your body absorb', then we have you covered.
How your body processes protein
Protein digestion begins in the stomach and continues into the small intestine. Here the protein is broken down into its building blocks (amino acids) where they are then absorbed into the bloodstream.
When we exercise we cause micro-tears in the muscle fibres that need repairing. Then in comes muscle protein synthesis. Muscle protein synthesis is the process where the body uses these newly available amino acids to repair and build muscle tissue.
Maximum protein absorption rate per hour
The body can absorb amino acids from protein at a rate of 8-10 grams per hour, depending on the protein source (whey protein is faster absorbing than casein protein, for example).
It is often proposed that muscle protein synthesis is maximised when you consume around 20-25 grams of protein in one feeding. But there are many factors that influence optimal protein intake and to look at protein in an individual feeding window just isn't helpful.
Just to add a little confusion here, if you're looking for an exact answer to 'how much protein can your body absorb in one sitting', then the research is still pretty inconclusive. One research paper found that 20g of protein was enough to maximise muscle protein synthesis in young men (Schoenfeld & Aragon 2018), whereas another research paper found that eating 90g of protein in one sitting did not stimulate muscle protein synthesis more than consuming 30g of protein. The general research finding seem to be that if you aim for 20-30g of protein per meal, then you will be pretty close to maximising muscle growth.
Common Myths About Protein Absorption
Myth: "The body can only absorb 20-30 grams of protein per meal."
This is a very common misconception. While MPS may plateau at around 20-40 grams per meal for most people, the body can still use and absorb the protein for other functions (like enzyme production, immune support, etc.). Excess protein isn't 'wasted', it is simply utilised in other bodily processes.
Myth: "Eating more protein in one sitting is harmful."
There’s no conclusive evidence to suggest that consuming higher amounts of protein in a single meal is harmful for most people, as long as the individual is generally healthy. However, for individuals with kidney issues, protein intake should be monitored more closely.
How much protein should you eat per meal for muscle gain?
The UK Reference Nutrient Intake (RNI) for protein is 0.75 grams of protein per kilogram of body weight per day, which is around 56 grams for the average male and 45 grams for the average female. These recommendations are to prevent deficiency, rather than optimise intake - especially if you have additional fitness goals.
Optimal Protein Intake for Athletes: According to the International Society of Sports Nutrition, for muscle growth and athletic performance, an overall daily protein intake in the range of 1.4–2.0 g protein/kg body weight/day (g/kg/d) should be sufficient for most exercising individuals.
Protein rich foods for muscle gain
Common dietary protein sources include chicken, eggs, fish, dairy products (like milk and yoghurt), legumes, and plant-based alternatives like tofu and seitan.
High-Quality Protein: Animal proteins such as beef, fish, and dairy contain all the essential amino acids that your body needs for muscle protein synthesis. However, plant-based proteins can still provide sufficient amino acids when combined properly to ensure all amino acids are present, for example: rice and beans.
The UK’s Eatwell Guide encourages getting protein from a variety of sources, including plant-based ones, to ensure a balanced intake .
Practical advice for maximising muscle protein synthesis
Timing of Protein Intake: The research suggests that it would be beneficial to spread your protein intake evenly throughout the day rather than consuming large amounts all in one sitting. Aim for 20-30 grams of protein per meal multiple times per day to help maintain steady muscle protein synthesis levels.
Post-Workout Protein: Consuming protein after exercise has been shown to be particularly effective for boosting muscle protein synthesis. Aim for 20-25 grams of high-quality protein post-workout.
Protein Supplementation: Whey protein is a popular and fast-digesting supplement often used post-workout for rapid amino acid delivery. Whey protein has the highest protein bioavailability rating of all protein supplements - a high protein bioavailability means that it is a very efficient protein source at providing your body with the amino acids that it needs. Casein protein, a slower-digesting protein, is often consumed before bed to provide a steady supply of amino acids overnight.
Other factors affecting protein utilisation
Age: Our ability to utilise the protein that we consume decreases with age. Therefore, older adults may require more protein per meal to stimulate the same level of MPS as younger individuals. This might be closer to 40 grams per meal for those over 60 years of age.
Caloric Surplus/Deficit: If you are in a calorie deficit (trying to lose weight), then your protein requirements may increase to prevent additional muscle breakdown. When you are in a calorie deficit/trying to lose weight it is essential to ensure adequate protein intake to preserve your lean muscle mass.
Training Status: Individuals with more muscle mass or those engaging in high-intensity resistance training may require more protein to support muscle repair and growth.
How much protein can your body absorb: to sum it all up
We hope that you have found this 'how much protein can you absorb in one sitting' blog post helpful! Here are the key takeaways:
Protein absorption is not capped at 20-30 grams per meal as the body utilises protein for various functions beyond muscle building.
For optimal muscle growth and muscle protein synthesis, aim for 20-40 grams of protein per meal. Aim to spread these protein feedings across the day.
Individual needs vary based on factors like age, muscle mass, and training frequency, but balanced, consistent intake is key.
Practical guidelines for athletes suggest 1.6-2.0 grams of protein per kilogram of body weight per day.
References:
Schoenfeld & Aragon (2018), How much protein can the body use in a single meal for muscle-building? Implications for daily protein distribution
T Symons, et al (2008), A moderate serving of high-quality protein maximally stimulates skeletal muscle protein synthesis in young and elderly subjects
International Society of Sports Nutrition Position Stand: protein and exercise
Protein Digestion and Absorption - NHS (National Health Service)
Protein and Muscle Mass: The Effects of Protein Intake on MPS - PubMed
Dietary Guidelines for Protein Intake - British Nutrition Foundation
Protein Needs for Athletes - UK Sport & Exercise Nutrition Register (SENr)
Eatwell Guide on Protein - Public Health England
Protein Timing and Muscle Growth - Journal of the International Society of Sports Nutrition
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