Protein is a crucial macronutrient for many fitness goals including muscle-building and weight loss. But, you can have too much of a good thing.
Whether you're getting calories from protein, fat, or carbs, consuming more per day than you burn off will always lead to weight gain, explains Emily Kyle, RD, the co-owner of Emily Kyle Nutrition.
Plus, not all protein sources are equal: "High-fat, processed sources of protein consumed in high amounts can lead to negative health outcomes and increase risk factors for heart disease, high blood pressure and cancer," says Maggie Michalczyk, RDN, founder of Once Upon a Pumpkin. "Eating quality sources of protein in sufficient amounts is key."
Trying to get more protein in your diet, but want to make sure you're doing it in a healthy way? Here's what you need to know about how eating a high-protein diet *could* lead to weight gain, and ways to make sure you’re taking in just the right amount.
Meet the experts: Bonnie Taub-Dix, RD, is a nutritionist and the author of Read It Before You Eat It – Taking You from Label to Table.
Emily Kyle, RD
, is a nutritionist and co-author of The Clean Eating Meal Prep and The 30-Minute Thyroid Cookbook.
Keri Gans, RD
, is a nutritionist and the author of The Small Change Diet. Maggie Michalczyk, RDN, founder of Once Upon a Pumpkin.
Christy Brissette, RD, is the founder and president of80 Twenty Nutrition
, RD, runsMPM Nutrition
in New York.
How can eating too much protein lead to weight gain?
Here are four reasons your protein intake might be causing the number on the scale to tick up.
- You’re eating too much meat. While that marbled ribeye will definitely help you feel full, it also packs more calories than you probably bargained for: A 10-ounce steak—a small restaurant portion—can clock in at 1,000 calories. “Those excess calories don’t go to your biceps. They turn into fat,” says Bonnie Taub-Dix, RD, the creator of BetterThanDieting.com and author of Read It Before You Eat It.
- You’re setting yourself up for binges. Cutting out too many carbs can put a damper on your mood and make your body crave starch and sugar, which can lead to binges. “Your brain’s preferred fuel source is glucose, or carbs,” says Kyle. When you do eventually have carbs again, there’s a good chance you’ll overdo it and undo all of the progress you’ve made. “Usually when my patients are really being strict on protein diets, even a piece of Melba toast looks delicious,” says Taub-Dix.
- You don't have the energy to work out. “Carbs are the best source of fuel for any activity,” says Taub-Dix. Cutting them out entirely to make way for protein can also cause you to feel tired, which means you end up working out less—and that’s counter-productive to any weight-loss plan. “It’s a revolving cycle. You feel lethargic so you don’t work out, and you don’t work out so you feel more lethargic,” adds Kyle.
- You’re not getting enough fiber. Fiber absorbs fluid to help you feel more full and keeps your GI tract in tip top shape by feeding healthy gut bacteria, and lots of studies have linked fiber to weight loss. But if you’re focusing too much on protein, you might not get enough fruits, veggies, and whole grains—major sources of nutrients and fiber that can help you feel more satisfied with more volume for fewer calories. “If you’re eating too much protein, you’re not fueling the good bacteria in your gut,” says Taub-Dix.
What are the signs and symptoms of eating too much protein?
As you know, weight gain isn’t really a health issue (it’s normal!) unless it’s impacting other parts of your body or contributing to adverse conditions. That said, there are actual problems that can be caused by eating too much protein. "While protein is necessary for optimal health, consuming too much protein on a regular basis can contribute to various health issues and conditions," confirms Michalczyk. Here are some additional symptoms to look for:
- You’re feeling extra thirsty. If your mouth is super dry, there’s a protein-linked reason for that. Your kidneys have to work doubly hard to flush out excess protein through your urine, and that can make you really thirsty, says nutritionist Christy Brissette, RD, the founder and president of 80 Twenty Nutrition. Because you’re peeing out more sodium, potassium, and magnesium, “people on high-protein/low-carb diets tend to need more of these electrolytes,” she says. And take note: Long term consumption of excessive protein may put strain on the kidneys and increase the risk of developing kidney-related issues, per Michalczyk.
- You’re constipated or have diarrhea. “If you cut out all whole grains, nuts, seeds, veggies, and fruit, all of which are good sources of fiber, it can lead to issues with digestion including constipation,” says Brissette. A high-protein diet can also rid your gut of helpful bacteria. “If gut flora are out of whack, it can lead to bowel irregularities including diarrhea or alternating diarrhea and constipation, and you might experience some bloating and cramping,” she says.
- You’re super moody lately. A quick PSA: Only eating protein-dense foods can put you on edge. “If you aren’t correcting imbalances in your gut bacteria, research links your gut microbiota to mental health, depression, and anxiety,” says Brissette. “Carb-rich foods increase levels of serotonin in your brain, which is a happy neurotransmitter,” says Brissette. “By not getting enough carbs, certain people will notice a change in their mood and outlook.”
- Your breath is smelly. If you’re on a super low-carb diet, bad breath is a common sign of ketosis, a process where your body has churned through all your stored carbs and is instead burning fat for energy, explains nutritionist Vandana Sheth, RDN. However keep in mind that going into ketosis can be dangerous, especially if you have other health conditions. Talk to your doctor before committing to a ketogenic diet.
- Your menstrual cycle changed. Cutting out carbs for too long can stop you from getting your period, too. When you burn through too many fat stores, that can change your metabolism in a way that impacts your hormone levels and fertility. “Your body is going into preservation mode. It’s a sign your body is under stress, and it isn't a good time to bring a baby into the world because food is scarce,” says Brissette. Basically, women need a certain amount of fat for proper hormone levels, fertility, and overall health, so you should head to the doctor if you notice your protein intake is impacting menstruation.
What is a healthy amount of protein to eat every day for weight loss?
Remember: Everyone’s different, so there’s really no one-size-fits-all prescription when it comes to a healthy amount of protein for you. “Protein intake really depends on your size and activity level, but there are some numbers we can look at,” explains Marissa Meshlaum, RD, who runs MPM Nutrition in New York.
“The Recommended Dietary Allowance (RDA) for protein is set at 0.8 grams of your body weight, but that is a minimum, not necessarily optimal,” Meshlaum notes. TBH, your best bet is to try and get roughly 30 percent of your calories from protein. This rounds out to be about one gram of protein per pound of body weight, Meshlaum says. (And yep, the more active you are, the more protein you will need for optimal muscle recovery.)
How can I make sure I'm eating a healthy amount of protein and not going overboard?
Okay, so now that you know the risks and symptoms associated with eating too much protein, it’s time to focus on how you can keep protein in your daily diet without going overboard. Here are some tips for eating protein in a healthy way, according to dietitians.
- Go for high-protein, low-cal, plant-based foods. As often as possible, opt for veggies and dairy that are high in protein but still low in calories. A cup of Greek yogurt or beans, for example, net you around 15 grams of protein for less than 200 calories. And when you do eat meat, choose lean cuts and keep your portions in check. One serving should be about the size of a deck of cards, says Taub-Dix, and you can try yummy veggie-protein combos like this steak and apple watercress salad.
- Eat your carbs, folks. To keep things in balance, Taub-Dix suggests getting about 50 to 55 percent of your daily calories from healthy carbs. “Carbs are the nutrient we love to hate, but in reality you can still lose weight eating carbs,” she says. Great, weight-friendly sources include whole grains, fruits, and veggies, all of which can be found in this baked potato skins recipe.
- Don't forget that fiber is your friend. Make sure you’re hitting your daily recommended intake of about 25 to 30 grams of fiber daily. Good sources include fruits, vegetables, and whole grains. “One way to ensure you're eating a healthy amount is to use the plate method,” says Keri Gans, RD, the author of The Small Change Diet. “One-quarter of your plate is protein, one-quarter of your plate is carbs, and half your plate is veggies.” For serious inspo, check out this sautéed chickpeas and spaghetti squash bowl.
- Maintain regular exercise. "I think the best way to keep your weight stable is [to] exercise regularly along with eating a diet that's well-rounded with a balance of protein, carbs and healthy fats," says Michalczyk. And as noted, to maintain your weight, it's important not to consume more calories (of any kind) than you burn. So in theory, fitting in time for exercise could make it so you could consume slightly more cals in the form of protein without gaining weight. Since protein is used to repair tissue, which is how your muscle recovers, there's a sort-of virtuous cycle effect, too.
What are the best sources of protein to eat for weight loss?
Not all protein sources are created equal—some are better for weight loss than others.
- Chicken thighs. Chicken breast is the more traditional low-calorie protein option, but the higher fat content of chicken thighs increases satiety and it’s more flavorful. “Additionally, because of the higher fat content chicken thighs hold up better in moist heat cooking like braising, which allows even more flavor development and a juicier end product,” Wilson notes.
- Eggs. Eggs are incredibly filling and a great on-the-go snack. They can be enjoyed hard-boiled, poached, or scrambled. “Eggs have a bit of fat, which is partly what makes them so filling,” says Audra Wilson, RD, CSOWM, a bariatric dietitian at Northwestern Medicine Delnor Hospital. “Filling proteins help us to eat fewer calories overall because they really quell hunger without the crash like after eating strictly carbohydrates.”
- Fish. Fish is the animal protein lowest in fat but still just as high in protein, says Wilson. Fish is quick to cook even from frozen or can be enjoyed anywhere like a tuna or salmon pack.
- Lean beef. “Lean beef is a good option to mix in for variety and if you purchase lean beef and drain the fat after cooking,” says Wilson. Limit it to one to two times per week, though. The fat in beef imparts flavor and provides satiety. Top it with lots of veggies for additional filling fiber. Pro tip: Get the leanest option available like 90/10 unless you are making burgers on the grill, where 80/20 would be more appropriate.
- Lentils. “Lentils are technically deemed carbohydrates because of their higher carb count, but their fiber and protein make them very filling so a small portion goes a long way,” says Wilson, who recommends combining lentils with tofu and veggies for a high-protein and fiber plant-based meal option.
- Low-fat cottage cheese. Low-fat cottage cheese packs lots of protein in a small number of calories. It can be paired with fruit for a quick breakfast or post-workout snack. Cottage cheese is savory and satisfying with a little bit of carbohydrates and fat.
- Plain Greek yogurt. Plain Greek yogurt contains a good balance of protein and carbohydrates. It also goes great with almost anything. “You can use it with berries for a sweet and satisfying breakfast, add it to any creamy dish to increase protein, use it to prepare savory dips and sauces, which are much lower in fat and higher in filling protein than their sour-cream-based counterparts or use it in place of sour cream on tacos or in chili,” says Wilson.
- Pork tenderloin. Tenderloin is a super lean cut of pork. The size and shape of the tenderloin make it perfect for meal prep. Just two to three slices can easily be portioned out for many meals, says Wilson. You can also flavor the tenderloins differently and bake or roast a few at the same time, giving you lots of lean protein ready for later use.
- Rotisserie chicken. Rotisserie chicken breasts are a lean and tasty option for those in a hurry. Since it is cooked for a longer period, Wilson says most fat is rendered off of the meat, leaving a low-fat protein. The chicken is brined, making it a flavorful and juicy protein that can be eaten as it is or shredded for use in salads, soups, stews, or tacos.
- Tofu. Tofu is naturally high in protein and contains all the essential amino acids your body needs. Just like plain Greek yogurt, tofu has endless uses and can pick up any flavor profile. Silken tofu can be added to any dish to boost the protein content or as part of a creamy dessert, says Wilson.
- Turkey sausage. Turkey sausage has up to 75 percent less fat than traditional pork sausage, says Wilson. You can swap ground beef or pork with this alternative in any recipe to cut down on calories while still getting lots of protein. Pre-cooked, flavored turkey sausage options can also be a quick add-on to a salad or sautéed with fresh or frozen veggies and paired with rice or pasta for a super-quick and satisfying dinner.
Not-so-great protein options include full-fat dairy and processed meats. The high saturated fat content in both is not great for your heart, Wilson says, and the overconsumption of processed meats have been linked to a higher incidence of colorectal and stomach cancers.
“You can get just as much protein with far fewer calories and fat by opting for the low- or reduced-fat varieties of cheese, milk, and yogurt,” she adds. But Wilson does not recommend fat-free dairy, as the flavor and texture can be off-putting for some.
Colleen de Bellefonds
Colleen de Bellefonds is an American freelance journalist living in Paris, France, with her husband and dog, Mochi. She loves running, yoga, and wine, and is very particular about her baguettes.
Ashley Martens is a Wellness Writer based in Chicago, Illinois. With a digital marketing background and her knowledge of general nutrition and a lifelong passion for all things health and wellness, Ashley covers topics that can help people live happier and healthier lives.
Emily Shiffer is a freelance health and wellness writer living in Pennsylvania.