No, there is no maximum amount of protein your body can absorb in an hour

Context

Videos circulating on TikTok claim that the human body can only absorb a specific amount of protein in a single time frame or during a single meal, and any surplus protein is converted to alternate organic acids within the body or oxidized for energy. In one example, a man with over 18 million likes on his profile says that, in general, protein is incrementally absorbed within your gut on a strict 30-40g per hour rota. However, this claim is false because it is not supported by scientific evidence and has been debunked by several studies.

In fact

Protein is a vital macronutrient made of amino acids used by our bodies as the basis of hair, skin, and muscle tissue. The Recommended Dietary Allowance (RDA) for an average adult per day is about 0.75g of protein per kilogram of body weight, which amounts to roughly 50g. This is purely to sustain and maintain normal bodily functions and meet basic nutritional requirements to keep the body functioning correctly. However, athletes who prioritize resistance training specifically for muscle building have a higher protein requirement due to their want or need to actively put on muscle mass. Athletes, therefore, aim to consume more protein throughout their day, often splitting the amount across meals for ease of consumption.

What is MPS?

Muscle protein synthesis (MPS) is the metabolic process that describes how amino acids incorporate themselves into in situ skeletal muscle proteins. In short, MPS is the key factor in how the body adapts to exercise and is commonly used to measure the long-term effectiveness of short-term actions like exercise and nutrition. It is usually defined over a specific time period, such as an hour or a day, purely because this measurement can be and is used as a tangible way for athletes to plan their meals around lean muscle building.

The National Library of Medicine and other studies

Studies show that the relationship between protein intake and MPS is positive, which means that the larger the protein consumption, the larger the MPS response. There is indeed a burning of excess amino acids for bodily energy, but this is minor compared to the amount of protein used for MPS.

Sports science research has shown no strict maximum for protein intake, and this is only a scientific recommendation specifically for MPS. Furthermore, to ensure the target intake is explicitly reached for muscle building, scientists further recommend splitting this into protein weighing 0.4g per kg of body weight per meal across a minimum of four eating sessions throughout the day.

The claim of a 30-40g per hour absorption rate is longstanding despite being debunked by some studies proving that there is no upper limit to protein intake in humans. Research has shown that even if a person consumes an extensive amount of protein in a single sitting, it is still converted into muscle building at a slower rate. 

The verdict

While there is a recommended protein ingestion amount for athletes to optimize lean muscle building, there is no evidence of the maximum amount of protein your body can absorb in a single period or eating session. Therefore, we have marked this claim as false.

(This story was updated on June 6, 2024, to correct the figures for the recommended daily intake of protein.)