- Protein is an essential macronutrient but there are many myths and misunderstandings circulating about how much protein a person should consume on a daily basis, and what the best sources of protein are.
- Additionally, some people, such as those taking GLP-1 medications for weight loss, often hear that they should up their protein intake more than their peers.
- So what’s fact and what’s fiction, and what should we really know about protein in diet? Two experts, a bariatric surgeon, and a dietitian, answer some of the most widely asked questions.
“Protein is vital for numerous functions, including hormone regulation, the structure and repair of bodily components, digestive health, and muscle maintenance,” Mir Ali, MD, bariatric surgeon and medical director of MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center in Fountain Valley, CA, told Medical News Today.
It is an essential macronutrient obtained widely from diet, and not getting enough protein can lead to serious Health issues, including malnutrition and loss of muscle mass.
As Michelle Routhenstein, MS, RD, CDCES, CDN, preventive cardiology dietitian at EntirelyNourished further explained:
“Protein is essential to human health. It’s needed to repair tissues, make hormones and enzymes, support immunity, and build and maintain muscle and bone. Adequate protein helps with muscle strength, physical performance, energy balance, recovery, satiety, healthy aging, and cardiometabolic well-being.”
But can you have too much protein, do some people need more than others, and what are the best protein sources? Ali and Routhenstein have answered these, and other key questions, for MNT.
Everyone is likely familiar with the notion that fish and meat are the top sources for protein. And there is a widely circulating idea that certain amino acids — the molecules that make up proteins — can only be obtained from meat sources.
This has, further, led to the idea that people who follow a plant-based diet may not be getting all the protein they really need.
Routhenstein, however, told us that this is inaccurate. “There’s a common myth that you cannot get all your essential amino acids from a plant-based diet, but that’s not true,” she said.
“‘Complete’ proteins contain all nine essential amino acids, which are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine,” the dietitian explained.
She advised that:
“Animal foods like meat, poultry, eggs, dairy, and fish are typically complete proteins, meaning each contains all nine essential amino acids in adequate amounts. Several plant foods, including soy (tofu, tempeh, edamame), quinoa, buckwheat, hemp seeds, and chia seeds, are also complete proteins. For other plant protein sources, eating a variety of beans, lentils, whole grains, nuts, and seeds over the course of the day easily provides all the essential amino acids your body needs.”
Ali agreed, noting that, while “certain components, such as collagen, elastin, and myoglobin, are primarily available in animal protein […], alternative sources, such as vegetable-based proteins, are also adequate.”
“Recommended protein intake is typically based on a healthy target weight, usually ranging from 0.75 to 1.0 g/kg [grams per kilogram] of body weight,” Ali advised. “This varies based on age, activity levels, and other factors.”
“Once a goal is determined, apps and other resources can help track intake to ensure adequate consumption,” he suggested.
According to Routhenstein, “the first step [to ensuring your intake is adequate] is knowing how much protein you need to maintain or build muscle, depending on your goals.”
“For active adults without any kidney issues, aim for at least 1 to 1.2 grams of protein per kilogram of body weight per day, spread across meals,” she said. “Include a mix of lean animal and plant proteins, or focus on a variety of plant proteins if following a plant-forward diet.”
People who use GLP-1, or semaglutide, drugs like Wegovy for weight maintenance purposes, may have heard that they should up their daily protein intake.
This, both Ali and Routhenstein confirmed, is correct.
GLP-1 medications, Routhenstein explained, work by “reduc[ing] appetite and slow[ing] digestion, which can make it easy to unintentionally eat too little protein.”
If protein intake drops while losing weight, you may lose lean muscle. Prioritizing protein helps preserve muscle, support metabolism, and keep you full even on fewer calories,” she advised.
“It is important to maintain sufficient protein intake during any weight loss program to preserve muscle mass while burning excess fat,” Ali also emphasized.
A popular option for supplementing protein intake are protein shakes, or protein powder but these have also been linked to dangers such as overeating and blood sugar spikes.
According to Ali, “protein shakes are a beneficial source of supplementation for those who may struggle to meet their protein requirements through whole foods alone.”
Routhenstein agreed, noting that shakes “are especially convenient for people who lift weights or train regularly and may struggle to get enough protein from whole foods alone.”
However, she cautioned that these “should supplement, not replace, nutrient-dense lean proteins from whole foods.”
“What matters most is the total protein amount and quality,” she told us.
Both experts warned that, while protein is certainly key to maintaining good Health, people should not fall into the trap of boosting their intake to a point where it becomes perilous rather than helpful.
“Eating protein well above your needs can have downsides,” Routhenstein pointed out. “It may strain kidney function in people with kidney disease, increase calcium loss in urine, and potentially contribute to vascular inflammation.”
“Excess protein can also displace fiber-rich plant foods and, if highly processed, may raise cardiometabolic risk,” she noted.
The dietitian advised that:
“Staying around 1.2 g/kg per day of quality protein is safe and effective for most Healthy adults, but your needs may vary based on lab results, medical history, and activity goals. It is best to consult a registered dietitian who can evaluate you personally and provide tailored guidance, especially if you have heart, kidney, or liver disease.”
