Sufficient Protein Intake: Quantity Required for Muscle, Energy, and a Healthy Lifestyle; Red Flags Indicating Overconsumption
Protein, a nutrient essential for building and repairing muscles, skin, hair, and tissues, can be found in a variety of food sources. Lean meats, fish, dairy, legumes, nuts and seeds, eggs, and certain plant foods are all good sources of protein [1].
A well-planned plant-based diet can meet protein needs and support a healthy gut [2]. However, it's important to note that the body cannot store protein, so it needs protein every single day [6].
The once-popular 'anabolic window'-a 30-minute post-exercise period believed essential for protein intake-is now seen as less urgent, as muscles remain receptive to protein over several hours [3]. Protein shakes should be approached with caution, as they may contain artificial ingredients and can cause digestive issues if fibre intake is low [5].
Animal proteins are called "complete" proteins because they contain all nine essential amino acids [1]. On the other hand, plant-based proteins are usually low in saturated fat and have no cholesterol [1]. Common types of protein supplements include whey, casein, plant-based (pea, rice, soy, hemp), and collagen [7].
Excessive protein intake, particularly from animal sources, can strain kidneys, especially in those with pre-existing kidney conditions. Chronic high intake of protein can strain kidney function, especially increasing pressure in the kidney’s filtering units (glomeruli), causing hyperfiltration, which may contribute to kidney damage over time, particularly in individuals with pre-existing kidney issues [1][2][3][4]. However, evidence does not show significant harm in healthy people with normal kidney function, and some studies even link higher protein intake to a lower risk of chronic kidney disease (CKD), especially when protein is plant-based [1][2][3][4].
Athletes or those engaging in intense physical activity may require between 1.2 to 2.0 grams per kilogram to support muscle repair and growth [8]. Overemphasizing protein can lead to neglecting fats and carbohydrates, causing potential fatigue or nutrient imbalances [9].
Protein plays a key role in producing hormones like insulin and growth hormone [10]. Whole foods like eggs, lentils, yogurt, tofu, or fish deliver protein plus a bunch of other nutrients, making them a healthier choice compared to protein shakes [5].
It's recommended to consult a doctor if you have any digestive troubles or lactose intolerance [6]. Remember, protein shakes aren't magic meal replacements and should be used wisely, such as after a moderate to intense workout, when a protein-rich meal won't be consumed soon, for building or maintaining lean muscle, or for managing weight with a low-calorie, filling option [5][8].
In summary, while excessive protein intake can burden the kidneys, especially in those with predisposed conditions, moderate to high protein consumption from diverse, especially plant-based sources, is generally safe for healthy kidneys. Caution and medical supervision are recommended for individuals with kidney disease or other risk factors [1][2][4].
[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6172376/ [2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6251458/ [3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4859205/ [4] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6044855/ [5] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6251463/ [6] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6251461/ [7] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6172376/ [8] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4859205/ [9] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6251463/ [10] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6251461/
- Protein, a vital nutrient for building tissues, can be sourced from a variety of foods such as lean meats, fish, dairy, legumes, nuts, seeds, eggs, and various plant-based foods.
- A well-balanced plant-based diet can fulfill daily protein requirements while also promoting gut health.
- Animal proteins are called 'complete' proteins, as they contain all nine essential amino acids, while plant-based proteins are typically low in saturated fat and devoid of cholesterol.
- Protein supplements, including whey, casein, plant-based alternatives (pea, rice, soy, hemp), and collagen, are common in modern lifestyles and diets.
- A healthy lifestyle emphasizes balanced nutrition in food choices, including carbs, fats, protein, and essential nutrients like those found in eggs, lentils, yogurt, tofu, or fish, rather than solely relying on protein supplements.