Protein has been the most-loved macro for a while now. Want to lose weight? Up your protein intake! Want to see those muscle gains? More protein!
Truth: Protein is an important macro (as in macronutrient), to be sure. “Protein is made up of amino acids, the building blocks of muscle,” says Amy Kubal, RDN, a registered dietitian in Sioux Falls, South Dakota. “In order to preserve, repair, and grow muscle, protein is vital in your diet.”
Another truth: It is possible to go overboard on it. “You can eat too much of anything, including protein,” Kubal says. So…does that mean something bad will happen to you if you go to town on a big-honking steak? What about if you kinda got a little obsessed with chicken breasts over the last few months?
Here’s what you need to know about eating too much protein.
First: How much protein is the ‘right’ amount—and what’s too much?
If you want specific recommendations, the RDA recommends 0.8 grams of protein per kilogram of body weight. (To do quick math, divide your weight in pounds by 2.2 and then multiply that by 0.8 to get the amount of protein your bod requires, in grams.) So a 140-pound woman would want about 50 grams of protein per day.
But while that’s the current RDA, there’s been a growing movement toward recommending higher intakes of protein, particularly among active people. “As you age and the more active you are, you break down muscles during exercise,” says Kubal. “The recommendations for those populations needs to be higher in order to compensate for that.”
If you’re lifting weights regularly or are training for an endurance event, The American College of Sports Medicine (ACSM) recommends bumping your protein intake up to 1.2 to 1.7 grams of protein per kilogram of body weight, or 0.5 to 0.8 grams per pound. So for comparison, a 140-pound active woman should consume between 70 and 112 grams of protein.
Where you fall in that range depends on your needs and goals, and if you really want a customized recommendation, you’ll want to see a registered dietitian or a sports dietitian to plan out what’s right for you.
Wait—where does getting too much protein come in? “Ultimately, your body can only use so much protein,” says Kubal. That’s around 30 grams of protein per meal. For reference, that’s the amount you’ll find in half of a small boneless chicken breast—or a cup of cottage cheese plus two eggs is 34 grams of protein.
Research shows that spreading out protein intake during the day at each meal is best for muscle protein synthesis, particularly if you’re active and doing resistance training. Ideally, you want one-quarter of your plate to be lean protein at every meal. Options like chicken, turkey, lean cuts of steak are great, and Kubal also likes non-meat sources like cottage cheese, Greek yogurt, and eggs.
Watch women learn the answers to common food and nutrition questions:
What can happen if you eat too much protein?
Even if you went to town on steak tacos last night, you probably won’t suffer any side effects besides feeling pretty full. “Protein takes more energy to digest, and often you’ll feeler fuller compared to eating a carb-heavy meal,” says Kubal. If your goal is weight loss, then eating around 30 grams of protein at a meal can be a smart idea to boost the satiation factor of that meal. Above and beyond that, though, your body will metabolize and store excess protein as fat, she says.
In some cases, going overboard on protein can even be dangerous—but you’ll likely have been warned about this by your doctor if this applies to you. If you’ve been diagnosed with kidney disease, for example, a high-protein diet can further harm your kidneys. And if you have heart disease and are choosing fattier cuts of meat or processed meats (like hot dogs and sausage), then this type of higher-protein diet can also get you into trouble, says Kubal.
Some of the less-serious side effects you can expect if you’re eating too much protein, according to Kubal:
- Feeling uncomfortably full: Some people also find that eating a lot of protein “just sits like a rock in their stomach,” she says.
- Constipation: If you’re going overboard on high-protein foods, the risk is that these will displace other healthy foods or macronutrients—including fiber. “If you’re eating a big steak, you’re probably not eating a lot of veggies with that,” says Kubal. Remember, meat and dairy have no fiber, and your digestive system needs fiber to stay happy.
- Not being able to lose weight if you’re trying to: As mentioned above, any extra carbs your body can’t consume at a given meal are turned into carbs. That’s also why, if you’re a keto dieter, having too much protein might prevent you from going into ketosis.
An easy way to know if you’re eating too much is to look at your plate. “If your plate is centered around a 16 oz ribeye, you’re probably doing it wrong,” says Kubal. The old one-quarter protein, one-quarter starch (starchy veggies, whole grains), and one-half non-starchy veggies is an awesome—and easy—guideline for filling your plate properly. If these ratios are off in any direction, it’s an indicator you may be skimping on—or going overboard on—a particular macro.
What can you do if you’ve gone overboard on protein?
Relax! You can’t ruin your kidneys, gain weight, or do irreparable harm from a single meal, says Kubal. For right now, you can drink more water to help your kidneys move things through and flush the nitrogen from the protein out of your system, she recommends.
And then at your next meal, look at it as an opportunity to take in some of the other macronutrients your body may have missed out on lately—like complex carbohydrates, and healthy fats.
Above all else, check in on how you’re feeling. “If you ate 60 grams of protein at one meal, but you feel normal, you can eat normally at your next meal,” Kubal says. “If you didn’t have any veggies and are feeling off, then be sure to get those in.” Yet another instance when listening to your body is your best bet.