Ask the Dietitian: How Much Protein is Too Much?

Protein is crucial for healthy weight loss, building muscle and controlling hunger, and thanks to the buzz around low-carb, high-protein diets like Whole30 and Paleo, it can feel like protein is king. But, for all the good protein does, it is possible to overdo the macro.

If you were under your daily calorie needs, the protein would be broken down and converted into glucose (a sugar). This glucose is saved for use by the brain and kidneys because they don’t run on fat.

However, if you go over your daily calorie needs, the extra energy needs to be stored either as:

• Body fat, that can be burned for energy.
• Glycogen, that can be burned for energy.
• Actual muscle and organs, that is also functional, meaning it carries out important bodily processes (Think: breathing, detoxing, digesting). Muscles and organs can be tapped into for energy, but only as a last resort.

Extra calories will be stored regardless if they’re from carbs, fat or protein. But where they’re stored depends on their macronutrient identity. While the calories from fat can only be stored as body fat, calories from carbs and protein can go toward body fat or glycogen. Unless there’s a vacancy, extra calories are stored as body fat.

Extra protein is still special because we don’t automatically store it as energy. Instead, protein is prioritized for repairing or rebuilding muscle and other structures first before it’s stored as energy. In other words, you need a baseline level of protein to maintain lean mass — anything above this will be stored for energy.

The recommended daily allowance (RDA) for protein is 0.8 grams per kilogram of body weight.

To figure out your individual needs:

1. Divide your weight in pounds by 2.2 to convert it to kilograms.
2. Take that number and multiply it by 0.8 to get your RDA for protein.

For example, someone who weighs 160 pounds (72kg) would need to 58 grams of protein to meet their basic requirements.

This number may look low, but keep in mind that it’s what an average, inactive adult needs to prevent muscle loss. If your goal is to lose a little weight, anywhere between 0.8–1.2 grams of protein per kilogram (58–87 grams in the example above) will do.

For those with a goal to gain muscle, science suggests your protein needs are higher. Here is a guideline:

• For very physically active people, protein intake at 1.4–2 grams per kilogram of body weight is recommended by International Society of Sports Nutrition.
• This 2014 review suggests bodybuilders respond best when eating 2.3–3.1 grams per kilogram of body weight.
• A small study finds no additional benefit beyond 4.4 grams of protein per kilogram of body weight.

Too much protein can erode kidney and bone health over time. Processing protein creates toxic byproducts that our kidneys must work hard to remove. Some argue this weakens the kidneys and leads to chronic kidney disease over time. It’s a plausible claim, but still controversial since there’s not enough evidence to prove this link. Plus, a high-protein diet produces a lot of acids. The body draws on the calcium in bone to buffer acids. Over time, this loss of calcium leads to weaker, more porous bones (and health issues like osteoporosis).

In particular, eating too much meat — especially red meat — is linked to heart disease, Type 2 diabetes and cancer.

Unless you have a high risk for kidney issues, there’s no need to fear protein — on the flipside, there’s no reason to go overboard. You should strive to get enough of it every day from a variety of real food sources. Try adding more plant-based proteins (Think: beans, nuts, seeds) to your diet, too. Space out your protein consumption throughout the day so you digest and absorb it more efficiently. Finally, aim to balance the protein on your plate with healthy fats and complex carbs.