What Happens If You Eat Too Much Protein?

If you’re following the Paleo Diet, Whole30, a low-carb diet, or a very low-carb diet like keto, you’re likely eating higher amounts of protein each day. But here’s the thing: When you cut carbs, your protein and fat intake has to increase in order to meet daily energy needs. There are only so many fat calories that you can add to a salad or a cauliflower bowl, so it’s often easier to incorporate extra protein into meals and snacks.

But what happens if you eat too much protein? Searching online generates conflicting and confusing results. Some sources advocate the importance of increasing protein—particularly if trying to lose weight—while others suggest your risk of developing osteoporosis, kidney issues or cancer increases. So which one is it? Turns out there’s a little bit of truth to both sides. Here’s what you need to know.

Risks of Eating Too Much Protein

Regularly consuming too much protein, especially from animal-based sources, is associated with several increased health conditions. Here are potential risks that may make you want to monitor your consumption more closely.

Poor Bone Health

Calcium loss in urine increases with higher protein intakes, so many are quick to suggest that consuming higher amounts of protein weakens bones and increases risk of osteoporosis. But the calcium-protein relationship isn’t that simple. Bones need both calcium and protein, and the increased risk appears to stem from consuming less calcium than recommended—not necessarily the protein amount. If fact, when calcium is consumed at recommended levels, research suggests that intakes at or above the RDA for protein play a key role in bone health and possible osteoporosis prevention.

Cancer Risk and Heart Disease

Cancer risk is associated with protein, but in regards to specific protein foods—not overall protein intake. Consuming more than 3.5 oz of red meats and processed meats (such as hot dogs) each day is significantly associated with increased risks for both colon and rectal cancers. However, consuming protein from plant sources (such as beans, soy, nuts, and seeds) is associated with a decreased risk for most cancers.

The relationship between heart disease and protein is similar; it’s the protein source that matters most largely because protein foods from animals have higher levels of saturated fats. These fats increase one’s risk for the development and progression of heart disease, so it’s not surprising that higher intakes from animal proteins are also associated with an increased risk.

However, research suggests that choosing plant-based protein sources over higher-fat animal ones improves heart disease symptoms like blood pressure and cholesterol levels. These findings to-date from both cancer and heart research suggest that it’s key to watch the amount of protein coming from animal sources, particularly red and processed meats, and to incorporate more plant-based protein sources.

Kidney Damage

Kidneys play an essential role in removing waste product associated with the breakdown of protein, so consuming protein above estimated needs does put more work on them. This means individuals with chronic kidney disease or some type of kidney deterioration should not consume higher-than-recommended amounts of protein, and many benefit from restricting overall protein intake. But for healthy individuals, research suggests that higher protein intakes have no harmful effects on kidneys. However, increasing water and fluid intake is recommended to help the kidneys flush out additional waste from extra protein.

Potential Benefits of Protein

In otherwise healthy individuals, eating more protein can be beneficial if you're trying to shed a few pounds. Here's what research has to say.

Weight Loss

Research suggests that protein increases satiety and may decrease appetite and cravings, so many individuals consider incorporating protein into meals and snacks a key component to weight loss. A 2013 study in the American Journal of Clinical Nutrition found that individuals who consumed higher protein intakes (ranging from 15 to 50% of total calories from protein) had significantly greater satiety and less hunger in comparison to those who consumed around 14%. Similarly, another study found that when individuals consumed meals varied in protein content, but with the same total calories, those who ate the higher protein option felt full longer.

On the flip side, there’s the misconception that protein can’t be stored as fat. However, if calorie intake regularly exceeds calories burned then that extra energy is stored as fat—no matter if those calories come from carbs, fat, or protein. Also, animal-based proteins like red meat and dairy products may be higher in calories due to fat content. Looking at the big picture, increasing protein may aid in feelings of fullness—something that can be key when trying to lose or maintain weight. Just be sure to opt for leaner choices and watch serving sizes.

How Much Protein Do I Actually Need?

You should know how much protein you need in order to assess if you’re getting too much, so start by calculating needs and establish a range. The Recommended Dietary Allowance (RDA) for protein for a healthy adult is 0.36g per pound of body weight (0.8g/kg body weight) and is based on a person who gets minimal physical activity. And while there are higher protein recommendations for athletes, there aren’t guidelines for active individuals who aren’t athletes.

Many suggest that active individuals may have needs higher than the RDA. A 2016 study suggests that active individuals may benefit from 0.45g to 0.73g per pound of body weight (1.0 to 1.6g/kg body weight), depending on intensity and amount of activity.

How Much Protein is Too Much?

The exact answer is a bit complicated. While there isn’t a set limit for the amount of protein you should eat in a day, most health experts advise not going above 0.91g per pound of body weight (2g/kg of body weight). When assessing your daily protein needs, use your ideal body weight or a healthy body weight for height—not your actual weight—when calculating protein needs. Fat tissue doesn’t need protein, so using ideal weight approximates your needs based on lean body mass.