You’ve probably heard that protein is important, especially if you seek muscle gains in the gym. Even though protein is a good thing and something our bodies definitely need, how much protein is too much? Is really possible to eat too much protein, and is too much protein bad? We have all of your answers.

What is protein, and why is it important?

First of all, let’s look at the importance of protein. (I recently received my NASM-CPT, so let me impart some of my new knowledge to you.)

Protein is one of the three macronutrients (the other two being carbohydrates and fat) that serve a variety of important functions. According to the National Academy of Sports Medicine (NASM), “One of the main functions of protein is in the synthesis and repair of cells, tissues, and structures, such as collagen, elastin, and muscle. Proteins are also required for the synthesis of hormones, enzymes, antibodies, and peptides, as well as the transport of various compounds through the body, such as lipids and minerals.” Think of things like calcium. 

Bottom line: Protein is pretty darn important — and if we don’t get enough of it, our bodies pull from our skeletal muscle, which is the main reservoir of protein in the body. If you’re trying to build muscle, this is the last thing you want to do — which is why you want to make sure you’re consuming enough protein on a daily basis.

How much protein is too much?

If protein is so important, how much do you really need every day, and how much protein is too much? Back to my NASM textbook!

“The recommended dietary allowance (RDA) for protein is 0.8 g/kg of body weight and is considered to be a minimum amount of protein required to maintain nitrogen balance in the body to offset nitrogen losses that are a result of normal metabolic processes,” per the NASM. 

Wait, time out. Who cares about nitrogen? Well, according to the National Oceanic and Atmospheric Administration (NOAA), “All living things need nitrogen to build proteins and other important body chemicals.” DNA, RNA, you know minor things that support life. (Kidding, these are major things here, people!)

According to NASM, protein requirements increase under several circumstances including exercise, illness, and injury. Times of intense training, your monthly cycle, or pregnancy can cause your body to require more protein.

Under most circumstances, the actual protein intake of most individuals falls within the range of 10%-35% of total calories, considered the acceptable macronutrient distribution range (AMDR) for protein as a percentage of an individual’s diet. (This is according to the U.S. Department of Agriculture, by the way.)

Exercise can affect protein requirements from muscle breakdown and recovery, so here are some basic sports nutrition guidelines from various sports authorities.

• Sedentary adults: 0.8 g/kg of body weight (USDA Dietary Guidelines)
• Resistance and strength-trained athletes: 1.6-1.7 g/kg of body weight (Academy of Nutrition and Dietetics)
• Endurance athletes: 1.2-1.4 g/kg of body weight (Academy of Nutrition and Dietetics)
• Most exercising individuals (to build and maintain muscle mass): 1.4-2.0 g/kg of body weight (International Society of Sports Nutrition)

An individual’s needs for protein will vary depending on a number of factors including their goals, health conditions, intensity,  medical conditions, and training volume. Mary Sabat, RD, founder of Body Designs by Mary, also says protein needs can be dependent on a person’s activity level, age, gender, and weight.

What’s considered too much protein?

Two questions: How much protein is too much? And is there any danger of consuming too much protein?

Back to that good old NASM textbook: “Unless individuals have a medical diagnosis or condition that requires a limited protein intake, a higher-protein diet that provides greater than 2.2 g/kg of protein is unlikely to have an adverse effect for most healthy individuals and may help improve body composition, especially when combined with resistance training.”

However, some reported side effects of very high protein diets (protein consumption up to 2.2 g/kg of body weight) have been reported and could include constipation, gastrointestinal issues, increased excretion of calcium, and increased risk of kidney stones or gout.

Sabat says consuming excessively high amounts of protein can also put a strain on the kidney and liver, which are responsible for metabolizing and eliminating excess protein. It may also lead to dehydration due to increased water loss through urine.

Additionally, a high-protein diet may increase the risk of certain cancers, heart disease, and osteoporosis due to the increased excretion of calcium. Therefore, it’s essential to maintain a balanced and varied diet to avoid excessive protein consumption and associated health risks.

Oh, and just a heads up: Fluid intake should be increased when protein intake increases to facilitate the body’s removal of urea, a waste product from protein consumption.

If you have any specific goals or questions about your protein intake, connect with an RDN to determine your overall needs and the optimal range of protein that works best for you and your body.

Protein sources

A high-protein diet, particularly one that’s rich in animal sources of protein, may increase the risk of heart disease due to its association with high levels of cholesterol and saturated fat, explains Sabat, so make sure you’re eating high-quality protein sources and mix it up every now and then with some plant-based protein sources.

If you’re looking for some foods that are naturally high in protein, add these to your shopping cart ASAP.

• Almonds
• Black beans
• Chicken breast
• Chickpeas
• Cottage cheese
• Collagen
• Edamame
• Eggs 
• Fatty fish like salmon
• Greek yogurt
• Ground turkey
• Hemp seeds
• High-quality protein powders like blended plant proteins and whey
• Kefir
• Lean beef
• Lentils
• Nutritional yeast
• Oats
• Peanuts and peanut butter
• Pecans
• Peas
• Pistachios
• Quinoa
• Tofu
• Tuna fish

The bottom line on too much protein

Although protein is an essential macronutrient, protein needs will vary depending on a number of factors including your activity level, goals, and lifestyle. If you’re wondering how much protein is too much and if too much protein is bad, the good news is too much protein is tough to consume. But if you do, there aren’t too many negative side effects.

Just remember, optimal protein intake should support health, fitness, and performance goals without compromising the structure of an overall balanced diet that includes adequate nutrients for your needs.