14/09/2025
PROTEIN INTAKE CEILING – how much protein per meal can your body take?
It has long been said that you cannot digest more than 30 grams of protein in one meal. This idea of a “protein intake ceiling” derives from outdated research. Because scientists found higher nitrogen loss in the urine with higher protein intakes, they simply concluded that the extra protein was wasted and useless. We now know that this is not correct: protein metabolism is far more complex.
When you eat protein, your body breaks it down into its constituent amino acids and uses those to make its own proteins. When you eat lots of protein, your body can afford to replace more of its damaged proteins: protein synthesis and protein breakdown (protein turnover) increases. The raised level of urinary nitrogen therefore does not reflect a waste of eaten protein, but it is the excretion of damaged proteins, that have been replaced by new proteins.
The notion of a “protein ceiling” was also mistakenly confirmed by a study about the body’s muscle protein synthesis (MPS) response to different intakes of protein. They found that, in healthy adults, eating 90 grams of protein from 90% lean beef didn’t increase MPS more than 30 grams did.
But your body doesn't use dietary protein only to make muscle, or even only to make other proteins. Muscle tissue accounts for only 25–30% of whole-body protein turnover. The nitrogen from the dietary protein’s amino acids is also used to synthesize important nonprotein molecules, such as purines and pyrimidines, the building blocks for nucleic acids such as DNA and RNA. Excess amino acids can also be oxidized for energy.
These recent findings have also shifted the reference range of total protein intake per day. Where FDA still claims 0,8 grams of protein per kg of body weight is enough, this value is highly criticized by experts who consider it the bare minimum for sedentary young people. Physically active people and ageing individuals need far more protein to sustain muscle growth and prevent sarcopenia. Institutions like ISSN (international society of sports nutrition) for instance recommend intake of 2,2 grams/kg per day for active healthy persons, which can even safely be raised to 3 grams/kg/day.
CONCLUSION: Your body does not discard excess amino acids. Eating more than 30 grams of protein per meal does have benefits and is not wasted. Apart from stimulating muscle synthesis, it promotes repair and maintenance of other important molecules and tissues, keeping you strong, healthy and youthful.
