Everyone looking to gain lean muscle and lose fat has probably heard that consuming protein is a key part of the process. (Learn more about post-game nutrition.) But can you eat too much protein? The simple answer is yes, but there is more to the story. Read on to find out how much protein is safe for athletes.
The most common one is the concern about kidney function with a high-protein det. To understand this issue, you need to distinguish between "more work" and "damage." It's true that if you eat more protein, your kidneys have to do more work to break it down. However, this is not an entirely bad thing in healthy people, and it does not cause kidney damage.
Think of your kidneys as muscles. When you go to the gym and work out, your muscles get bigger and stronger by adapting to the stress you put on them. The kidneys are similar. If you look closely, you will see increased markers of more work being done, but no indications of damage. The kidneys work harder, but they soon adapt to the increased demand and go on their merry way without any complaints.
Dr. Lonnie Lowery has performed some great studies on this issue, since he got tired of hearing how higher protein intakes would cause your kidneys to explode out of your body and fly across the room (okay, maybe not). His most recent one was presented at the International Society of Sports Nutrition conference last year, which concluded: "A multi-year intake of ample protein among male Caucasian strength athletes does not affect common markers of renal (kidney) function." This was a multi-year study in strength athletes just like you. They were not looking at couch potatoes who ate more protein.
Of course, anything that can help you can also hurt you (including water). Thus, consumption of more than 1.5 grams of protein per pound of body weight is neither needed nor recommended.
When I teach nutrition, I give extra credit to anyone who can show me an actual peer-reviewed study of healthy people in which protein was considered bad for renal (kidney) health. After many classes, nobody has found anything, even though many nutrition textbooks will still tell you too much protein is not safe.
A higher intake of protein in healthy subjects has not been shown to be harmful to their kidneys. The kidneys may do work, but are able to adapt to the increased demand.
It's best to take around 1 gram of protein per pound and do not exceed 1.5 grams per pound. While there is no conclusive evidence that protein harms the body, anything taken in excess can have potentially damaging effects.
Get the scoop on protein through STACK's Protein Guide.
Glassock RJ. "Is the presence of microalbuminuria a relevant marker of kidney disease?" Curr Hypertens Rep. 2010 Oct;12(5):364-8.
Lonnie M Lowery, Allison Daugherty, Brian Miller, Sarah Dye and Loren Liming. "The effect of habitually large protein intake on renal function of strength athletes: an update." Journal of the International Society of Sports Nutrition, 2011, 8(Suppl 1):P33 doi:10.1186/1550-2783-8-S1-P33
Lorena Devia, Josh Huffman, James Mihevic, Anna Huszti and Lonnie Lowery. "Dietary protein, resistance training and health: a call for evidence." Journal of the International Society of Sports Nutrition, 2008, 5(Suppl 1):P23 doi:10.1186/1550-2783-5-S1-P23