562 Grams of Protein a Day?!

Do you know someone who still believes that high-protein diets are bad for the kidneys or liver? Here’s something to set the record straight. And while we’re at it, discover a study that pushes the boundaries of protein intake!

For years, we’ve been told that consuming too much protein would damage our organs. But is this really true? Spoiler alert: No. It’s like saying the Earth is flat or that all politicians always tell the truth. In short, a persistent myth.

Let’s first explore where this idea comes from and then see what modern research says about very high-protein diets.

The Origin of the Protein Myth

The liver and kidneys play a key role in protein metabolism. The kidneys filter waste like urea, while the liver processes amino acids. Some researchers theorized that excessive protein intake could overload these organs. But this hypothesis was based on studies conducted on people with kidney disease. For these patients, limiting protein sometimes helped, but not always.

What’s curious is how this idea was generalized to the entire population, even healthy individuals. It’s like saying that because some men with heart problems die during sex, everyone should stop having sex. (And for the record, no one has ever died from “too much protein.”)

Other factors have fueled this fear:

• Animal studies: Some research on animals suggested negative effects, but metabolic differences make these results largely inapplicable to humans.
• Institutional bias: Public health organizations worried that eating too much protein would lead people to avoid grains. That probably upset a few lobbyists.
• Vegan activists: To reduce animal product consumption, some groups promoted the idea that protein harms kidneys.

What Modern Studies Say

Dozens of recent studies show that high-protein diets are not only safe for the kidneys and liver but also offer numerous benefits:

• Metabolic health: Improved blood sugar and lipid levels.
• Muscle maintenance: Especially important for aging individuals.
• Fat loss: Protein increases satiety and thermogenesis, promoting weight loss.

Even for people with kidney or liver issues, current recommendations no longer call for drastically reducing protein. Some doctors take a moderate approach, but that’s more out of caution than necessity.

The Bodybuilders’ Study: An Extreme Experiment

A recent study pushed protein intake to unprecedented levels. Five bodybuilders, already on high-protein diets, were followed for two years. Their protein consumption increased significantly:

• Subject 1: Up to 255 g/day for 93 kg (205 lbs).
• Subject 2: Up to 285 g/day for 73 kg (161 lbs).
• Subject 3: A record-breaking 562 g/day for 99 kg (218 lbs).

Results? No significant negative effects on the kidneys or liver. Some clinical values were temporarily outside normal ranges but had no pathological consequences. The subject who consumed over 500 g/day even reduced their body fat percentage from 18% to 13%.

Practical Tips

You don’t need to consume 500 g of protein a day. But this study shows that fears surrounding protein are unfounded. Here are some useful guidelines:

• To control appetite: 15–25% of daily calories from protein (around 85–138 g/day).
• To build muscle: 1.6–2 g of protein per kilogram of body weight.
• To lose fat and stay full: 2.2 g per kilogram of body weight, or up to 2.5 g during strict cutting phases.

So next time someone tells you that protein will “damage your kidneys,” you’ll know what to say. And remember: your body is an incredible adaptive machine, capable of handling high demands, whether in fitness or nutrition!