The 2026 Levels Guide to the best protein sources

Getting enough protein is vital for better health—use this guide to determine the optimal mix of protein-rich foods to reach your goals.

WRITTEN BY

Stephanie Eckelkamp

REVIEWED BY

Zoë Atlas, MPH, RDN

Updated: 02/12/2026|15 min read

If you’re familiar with protein’s benefits—helping to maintain muscle mass, control blood sugar, produce hormones, and boost satiety at meals—you may already aim to get between 1.2 and 2.0 grams per kilogram of body weight each day (or roughly 25 to 30-plus grams per meal), depending on your activity level and health goals.

Meeting your protein needs while supporting optimal metabolic health isn’t as simple as checking nutrition facts. The idea of a high-protein, low-carb diet is often associated with thick cuts of steak, burgers, and loads of chicken breast—all highly concentrated sources of bioavailable protein. At the same time, we keep hearing about the health benefits of plant-based eating for metabolic health and longevity. And, of course, there’s protein powder, which diet experts tend to recommend as a supplement, not a primary source of protein.

So, how does it all fit together? Use this guide to clear up the confusion and learn how to think about the best mix of protein types in your diet for optimal health. (Spoiler: Variety is key!)

Why protein sources matter

Dietary protein is a macronutrient that provides the structural components required to build and repair every type of cell and tissue in the body, including bones, hair, nails, the intestinal lining, and, perhaps most notably, skeletal muscle via a process called muscle protein synthesis (MPS). Protein is also the most satiating or filling macronutrient, which can aid in weight loss, and it supports hormone production, immune health, and stable blood sugar by slowing the rate at which glucose from carbohydrate-containing foods is absorbed into the bloodstream.

When you eat and digest protein, it’s broken down into smaller molecules (or protein “building blocks”) called amino acids, which are then absorbed into blood circulation via the small intestine and taken up by cells throughout the body. Inside cells, these amino acids are used to build and repair tissues and help synthesize a range of vital compounds (hormones, enzymes, antibodies). The human body needs 20 different amino acids to function: Eleven are non-essential (your body makes them), and nine are essential (so you must get them from food).

What’s important to keep in mind, though, is that not all protein-containing foods have the same composition of amino acids, so you have to pay attention to the types of protein you’re eating. The most obvious difference is between animal proteins and plant proteins: Animal sources of protein like meat, fish, eggs, and cheese are considered “complete” as they contain all nine essential amino acids in the approximate proportions needed by the human body; while most plant sources of protein like nuts, seeds, whole grains, and legumes (with the exception of soy and hemp) have too little of one or more essential amino acids and are therefore “incomplete” on their own.

For example, a “limiting amino acid” (i.e., the essential amino acid present in the lowest quantity in a given food) in beans, lentils, and peas is methionine, while most nuts, seeds, and grains are low in lysine and threonine. This is why strictly plant-based eaters must consume a variety of plant proteins throughout the day (think: bean chili topped with pumpkin seeds) for optimal health. Eaten together, these different plant proteins compensate for each other’s shortcomings and result in an overall “complete” amino acid profile. Vegan-friendly essential amino acid supplements (like this or this), which contain isolated versions of all nine essential amino acids, can also be a convenient way to help cover your bases—though they haven’t been explicitly studied in the context of plant-based diets.

Beyond just amino acids, the nutritional makeup of different protein sources can vary significantly in several other ways, too. Here are a few to consider (we’ll elaborate on most of this later):

• Fat content and composition: High-protein foods can differ significantly in their amount and type of fat. For example, meats contain predominantly saturated and monounsaturated fats, but some cuts are much leaner than others; fatty fish are the best dietary source of omega-3s, while some other fish such as white fish are pretty low in fat; nuts and seeds have primarily monounsaturated and polyunsaturated fats; and most legumes have very little fat.
• Vitamins and minerals: Some protein foods are a concentrated source of certain micronutrients compared to others. For example: Meat (iron), seafood (iodine), fatty fish (vitamin D), eggs (choline), dairy (calcium), lentils (iron), edamame (magnesium).
• Fiber and phytochemicals: Plant (but not animal) protein foods contain healthy fiber and phytochemical antioxidants such as polyphenols, which may be one reason eating more plant proteins—and plants, in general—is associated with healthy aging and longevity.
• Protein density: Most animal proteins contain more protein per calorie or serving than plant proteins, making it easier to hit your protein goal with less food. But among plants, you can still find relatively protein-dense options like various soy foods and hemp seeds.
• Processing and additives: Highly processed protein foods, whether animal- or plant-based (e.g., processed meats, plant-based alternative meats, some protein bars and shakes), contain more additives and fewer naturally occurring micronutrients.

Given the nutritional profiles of different protein sources, many nutrition experts recommend considering your personal health needs (e.g., health conditions or habits that might increase or decrease your need for different nutrients) and then seeking out a variety of whole and minimally processed proteins from various food groups to support those needs. As opposed to loading up on just a couple of other protein sources, this will help you maximize nutrient intake and avoid getting too much of any single nutrient that may cause harm.

Animal vs. plant protein quality: What’s the difference?

Both animal and plant protein sources can be a great addition to your diet. But, in general, animal proteins are considered higher quality than plant proteins for these reasons:

1. They are complete proteins, meaning they contain all nine essential amino acids our bodies need in the approximate proportions required to function optimally.
2. They are highly digestible and bioavailable, meaning they are readily broken down into their individual amino acids. These amino acids are efficiently absorbed into the bloodstream and subsequently taken up by the body’s cells for use. Most animal proteins are 90 to 99% digestible, while plant proteins are often less than 85% digestible due to the presence of fiber and other plant compounds like phytic acid (so, fewer amino acids end up being absorbed from plants than from an equal amount of animal protein). However, it’s worth noting that there is debate about these so-called antinutrients.
3. They are a denser source of protein than plant sources—meaning you get more protein per calorie or serving, and they tend to have fewer carbs. For example, three ounces of chicken has 24 grams of protein, 0 grams of carbs, and 122 calories, while a cup of chickpeas has 14.5 grams of protein, 45 grams of carbs (12.5 grams of fiber), and 269 calories.

To better determine the protein quality of foods, scientists have developed protein quality indicators like the protein digestibility-corrected amino acid score (PDCAAS) and the digestible indispensable amino acid score (DIAAS). For each, a higher number equals higher quality.

• The PDCAAS formula compares (i.e., divides) the amount of the limiting amino acid in one gram of a protein-containing food to the amount of that same amino acid in one gram of a reference protein like egg or milk; this number is then multiplied by the food’s digestibility percentage to get a PDCAAS score ranging from 0.0 (low quality) to 1.0 (high quality). Results are truncated, or capped, at 1.0 or 100 percent.
• The DIAAS formula compares the digestible quantity of an essential amino acid in one gram of a protein-containing food to the amount of that same essential amino acid in one gram of a reference protein. This formula is repeated for each essential amino acid, and the lowest value indicates the protein’s quality. Unlike the PDCAAS, results aren’t capped at 1.0 or 100%, so certain protein foods that are a particularly potent source of essential amino acids and easily digestible could have a slightly higher score (e.g., whey protein isolate’s PDCAAS score is 1.0 while its DIAAS score is 1.09).

Using the PDCAAS formula as an example: Many animal proteins—including the milk proteins whey and casein, egg, ground beef, and tuna—have a score close to 1 (100 percent), which indicates that a food is highly digestible and provides sufficient quantities of all essential amino acids to the body. Plant proteins tend to have a lower score and are, therefore, somewhat less effective at meeting the body’s essential amino acid needs: Lentils, peas, and other legumes have scores ranging from 50 to 75 percent, and grains range from 40 to 55 percent. The significant exceptions are soy protein isolates and concentrates, which have PDCAAS scores of around 100 percent. Less processed forms of soy, such as soybeans and tofu, have lower scores (around 80 to 85 percent) due, in part, to the presence of other food components such as fiber.

Because of the differences in protein quality between plant and animal foods, there’s a general consensus that animal proteins are better at stimulating processes like muscle protein synthesis (MPS) than non-isolated plant proteins. But this doesn’t mean that plant proteins aren’t effective for building muscle—you may just need to eat a bit more of them. For example, some research suggests that MPS is maximized with an intake of 20 to 25 grams per meal of a high-quality protein such as whey protein, while other posits that 30 grams of protein may be ideal, especially for mixed macronutrient meals containing less easily digestible protein sources.

Keep in mind that protein quality, by definition, is not an indicator of a food’s overall healthfulness, so it shouldn’t be the only thing considered. As previously noted, protein sources can vary greatly in their other nutrients—so looking at the whole “protein package” is key.

What research on diet patterns can teach us about the health effects of different protein types

Health research loves to pit diets against each other—and often, when comparing diets rich in animal protein vs plant protein, the plants win. But this take is oversimplistic, in part because many observational studies don’t isolate for the health impact of specific animal proteins or plant proteins, despite there being significant nutritional variation within each category, and they don’t perfectly factor in the effect of other aspects of a person’s diet, lifestyle, or health that could skew results. Still, it’s helpful to see what broad patterns emerge in studies of diets rich in different protein sources. Here are some to consider, with some added nuance.

Protein sources and chronic disease risk

Diets rich in animal proteins tend to be associated with increased risk of chronic diseases compared to those rich in plant proteins, which contain unique health-protective nutrients such as fiber and phytochemicals (e.g., polyphenols). However, not all animal proteins carry the same risk. Based on several long-term observational studies, the main culprits appear to be red meat and processed red meats. Diets rich in these protein sources have been associated (to varying degrees) with Type 2 diabetes, cardiovascular disease, and cancer risk (especially colon cancer), and some studies suggest replacing them with other protein sources such as nuts, legumes, poultry, seafood, yogurt, and cheese might curb chronic disease risk.

A 2021 study analyzing data from nearly 150,000 adults found that people who reduced consumption of processed and unprocessed red meat over four years and replaced these with other protein-rich foods (poultry, seafood, low-fat dairy, high-fat dairy, eggs, legumes, or nuts) had a reduced risk of Type 2 diabetes over the next four years. Additionally, a 2022 meta-analysis found that replacing processed and unprocessed red meat with poultry, dairy, eggs, nuts, or legumes was associated with a lower risk of coronary heart disease. A 2019 meta-analysis also found that diets rich in legumes, soy, or nuts were associated with a greater reduction in LDL cholesterol—a risk factor for cardiovascular disease (CVD)— than diets rich in red meat.

But, when you look closer at these studies, you’ll see a significantly greater beneficial effect for eliminating processed red meat—which is more consistently and strongly associated with chronic disease than its unprocessed counterpart (more on why these are so bad later). Unprocessed red meat can still be a rich source of saturated fat, which may elevate LDL cholesterol, but a recent analysis of research found only weak evidence of its association with heart disease, cancer, and diabetes. Among different types of unprocessed red meat, there are also differing levels of risk: Eating lean unprocessed red meat (<10 g total fat, <5 g saturated fat, and <95 mg cholesterol per 100 g) is less likely to increase LDL cholesterol than fattier cuts.

Protein sources and healthy aging and mortality

Getting enough protein overall is vital for maintaining good health as you age, but some studies suggest plant proteins have an edge. A 2024 observational study on women found that for every three percent increase in calories from protein, people had five percent higher odds of healthy aging (defined as being free from 11 major chronic diseases, good mental health, and no impairments in memory or physical function). But when the effects of each type of protein were isolated, there were apparent differences: animal protein, dairy protein, and plant protein were associated with seven percent, 14 percent, and 38 percent higher odds of healthy aging, respectively. This supports a previous meta-analysis from 2020, which found that higher total protein intake was associated with a lower risk of all-cause mortality (death from any cause) in men and women, and higher intake of plant protein, specifically, had a more substantial effect and was also associated with reduced risk of cardiovascular-related death.

Again, whole-food sources of plant protein may have some benefits over certain animal proteins due to the presence of fiber, polyphenol antioxidants, and certain micronutrients. Researchers also point out that plant proteins tend to have a more favorable impact on blood pressure and cholesterol, and they are associated with lower levels of the hormone insulin-like growth factor 1 (high levels of which may increase the risk of cancer)—all of which may impact aging, disease risk, and mortality. Neither study compared plant proteins to specific animal proteins, though.

Interestingly, other research suggests that animal protein can have unique benefits for aging, too—particularly for maintaining physical function over time. In a 2021 study on older adults (average age 75), increased intake of animal protein, but not plant protein, was associated with reduced overall mortality risk; both animal and total protein were associated with reduced cardiovascular mortality risk. This beneficial relationship may be related to animal protein’s protective effect on muscle strength and function, which declines with age. The study authors note previous research showing that increased intake of total or animal protein was associated with increased muscle strength, which, in turn, was associated with reduced mortality. Older adults tend to need more protein per kilogram of body weight than younger adults due to altered protein metabolism and increased demands related to chronic and acute inflammatory health conditions—and including animal protein, which is protein-dense and easy to absorb, is an efficient way to meet those increased needs.

Protein sources and muscle mass

Diets higher in total protein are associated with having more lean body mass (which includes metabolically active skeletal muscle) and enhanced muscle strength compared to lower protein intake—and animal protein may enhance some of these effects, though research is mixed.

In a 2021 systematic review and meta-analysis comparing the effects of plant protein and animal protein, both types supported an increase in absolute lean mass and percent lean mass, but the impact on percent lean mass was greater for animal protein. Changes in strength, however, weren’t significantly impacted by the protein source. The researchers speculate that animal protein’s positive impact on lean body mass is related to protein quality—i.e., animal proteins provide all essential amino acids in sufficient quantities and are generally well digested, which enhances the absorption and utilization of amino acids for building muscle via MPS.

Additionally, some research suggests you need to consume more plant protein to achieve muscle growth similar to animal protein. For example, a 2024 study found that a four-ounce beef patty (27 grams protein, 279 calories) stimulated muscle protein synthesis similarly to an eight-ounce soy-based patty designed to mimic an Impossible Burger (41 grams protein, 462 calories) despite containing less total protein. The authors credit this to a greater and more rapid availability of essential amino acids in the blood following beef consumption.

Researchers speculate that animal protein, on average, is also a more potent stimulator of muscle protein synthesis due to its higher concentration of the essential amino acid leucine, which appears to trigger a more robust increase in MPS following protein intake. Results of a 2020 study seem to support this theory: Men and women who followed a 12-week resistance training program experienced similar increases in muscle growth and strength when they consumed whey protein or soy protein supplements matched for leucine content.

For people who are trying to optimize muscle gains and strength while controlling overall caloric intake, or those who may be struggling to meet a higher protein goal because they can’t physically eat enough food (like older adults with a reduced appetite), including animal proteins (dairy, meat, fish, eggs) and/or denser sources of plant proteins that contain higher levels of leucine (e.g. soy protein, edamame, tofu, tempeh, hemp seeds) may be a good idea.

Bottom line: When it comes to deciding which type of protein—animal- or plant-based—will better curb the risk of disease, maintain good health over time, and efficiently build muscle and strength, research suggests the answer doesn’t have to be either/or, it can be both.

Other factors to consider in choosing the best protein source for you

Certain groups may want to seek out more (or less) of certain protein-containing foods based on factors like their life stage and health status. While this list isn’t comprehensive, here are several populations to consider and how each may want to tailor their protein intake.

• Healthy, physically active adults: This group can generally be flexible and include a variety of whole and minimally processed protein sources for maximum nutrient diversity (more on the best options below)—and if building muscle and strength are key goals, including some animal protein may help you get there more efficiently. However, if you lean heavily on animal proteins with saturated fat, keep tabs on your cholesterol levels.
• Those at risk for high cholesterol (based on age, ethnicity, or family history): People who have elevated LDL or ApoB cholesterol or who are at higher risk—e.g., people with a family history of high cholesterol, people over age 40, people of Asian descent (e.g,. Indian, Filipino, Japanese, and Vietnamese), and post-menopausal women—should consider including ample plant protein sources in their diet, many of which also have heart-healthy fiber, and opting for animal proteins lower in saturated fat such as fish, lean meats, and certain dairy products.
• Women (pre- and post-menopausal): Interestingly, some women may experience a 10 to 15 percent jump in LDL cholesterol levels during menopause, so prioritizing plant proteins and leaner animal-based options could be wise at this stage. Additionally, some studies suggest that higher plant protein intake (about 3-4 servings per day from sources like soy/tofu, peas, beans, and nuts) before menopause may prolong female reproductive function and actually delay the onset of menopause.
• Older adults trying to maintain muscle: Adults over age 60 are at much higher risk of sarcopenia or age-related muscle loss, which can impair physical function and promote insulin resistance. Eating more protein helps counter muscle loss, and some guidelines suggest that older adults aim for 25-30 grams of protein per meal, making a point to prioritize leucine-rich foods (e.g. ,dairy, meat, fish, eggs, edamame, tofu, hemp seeds).
• People with chronic kidney disease: There’s not enough evidence to officially recommend one protein type over another for people with chronic kidney disease (CKD), but some research suggests prioritizing plant-based options may help preserve kidney function and slow disease progression by reducing the severity of hypertension (a primary driver of CKD) and reducing the phosphorus load of the diet (in CKD, kidneys can’t efficiently filter phosphorus, and animal foods are a bigger contributor). Some studies suggest getting about two-thirds of daily protein from plant sources may be beneficial.

Remember: There’s no one-size-fits-all approach for metabolic health—it’s about choosing what best complements your personal health needs and goals in the context of your overall diet.

A guide to the metabolic health impact of different protein sources

Getting a variety of different protein sources in your diet is essential to maximize nutrient diversity. But to really understand why, it’s helpful to examine the unique nutritional profile and health considerations for each of the protein source categories below.

Meat and poultry proteins: Beef, bison, chicken, turkey, pork, lamb

Most meat and poultry contain, on average, seven grams of protein per ounce plus micronutrients such as various B vitamins, heme iron (which is more bioavailable than the non-heme iron in plants), zinc, and selenium, all of which impact metabolic health in a variety of ways:

• B vitamins are vital cofactors in metabolizing all macronutrients (carbs, proteins, and fats), particularly in converting carbohydrates to energy.
• Iron helps transport oxygen via the blood to all bodily tissues to support their function, and it supports the function of mitochondria, which drives energy (ATP) production.
• Zinc plays a role in the proper processing, storage, secretion, and action of the hormone insulin, which regulates blood glucose levels. It’s also a key component of one of the body’s endogenous antioxidant enzymes [superoxide dismutase (SOD)](https://www.sciencedirect.com/topics/neuroscience/copper-zinc-superoxide-dismutase#:~:text=Copper%2DZinc%20Superoxide%20Dismutase%20(SOD,transport%20chain%20activity%20in%20mitochondria.), which helps neutralize the reactive oxygen species (ROS) that drive oxidative stress. (In excess, oxidative stress can promote inflammation, cell damage, and insulin resistance.)
• Selenium helps form the antioxidant enzyme glutathione peroxidase (GPx), which helps curb oxidative stress, and adequate selenium is essential for the secretion and action of insulin.

Together, iron, zinc, and selenium also support thyroid hormone metabolism and synthesis. In turn, nearly every organ in the body relies on thyroid hormone to regulate its metabolism. Selenium, for example, helps convert inactive thyroid hormone (T4) to active thyroid hormone (T3).

What else to consider

Some meat and poultry are relatively high in saturated fat, such as ribeye, beef short ribs, 80 percent lean ground beef, pulled pork, pork belly, and lamb shoulder. Depending on your overall diet and lifestyle, making these a primary food source could increase risk of high cholesterol, which can set the stage for CVD. Though you don’t need to eliminate these, be mindful to vary your protein sources if you have high blood lipids or a family history of heart disease. Leaner options with less saturated fat include:

• >90 percent lean ground beef
• Beef tenderloin
• Beef sirloin
• Flank steak
• Bison
• Pork tenderloin
• Pork loin
• Center-cut pork chops
• Lamb's leg
• Lamb loin chops
• Lamb shank
• Skinless chicken or turkey
• Ground turkey or chicken

In addition to saturated fat, meat and poultry can also vary in other aspects of their nutritional profile, and there are important considerations to help guide your intake.

• Iron content: Compared to other widely available meats, beef and bison have a higher iron content—a three-ounce serving of bison contains 2.7 mg iron (15 to 34 percent of the RDA for adult women and men, respectively), while the same amount of 90 percent lean ground beef contains 1.9 mg iron (11 to 24 percent of the RDA for adult women and men, respectively). If you have anemia or experience heavy menstrual periods, you may need to be more mindful about selecting iron-rich protein sources like these. Keep in mind: Bison is also slightly lower in calories, total fat, and saturated fat than beef.
• White vs. dark meat: White meat (e.g., chicken breasts) and dark meat (e.g., chicken thighs and drumsticks) poultry tend to be similar in calories but differ in several nutrients. Using one cup of skinless chopped chicken as an example: White meat contains 10 grams more protein, plus more vitamins B12, B3 (niacin), and B6. On the other hand, dark meat contains seven grams more total fat, two grams more saturated fat (which contributes to a juicer flavor and mouthfeel), and more iron, zinc, and vitamin B2 (riboflavin). Both can be part of a metabolically healthy diet, so consume both or choose whichever option you enjoy more or better meets your health needs.
• Grass-fed vs. conventional: Choosing 100 percent grass-fed, grass-finished beef, lamb, and bison could be metabolically advantageous for a few reasons. Grass-fed animals tend to be leaner than their grain-fed counterparts, and the fat they do contain is higher in anti-inflammatory omega-3s (though still much lower compared to fatty fish) and two to three times higher in conjugated linoleic acid (CLA). This polyunsaturated fat has been studied for its potential to support immune function, though more research is needed to establish the dose at which these effects would kick in for humans. Additionally, while the overall content of saturated fat is similar between grass-fed and grain-fed beef, some research suggests grass-fed meat tends to have a lower proportion of cholesterol-elevating saturated fats (myristic acid and palmitic acid) and a higher proportion of saturated fats with a more neutral effect on cholesterol (stearic acid).
• Processed vs. unprocessed: Opt for unprocessed, fresh meat and poultry, and scale back on or altogether avoid processed meats like cold cuts, beef jerky, sausages, and hot dogs, which can be high in saturated fat, sodium, and preservatives such as nitrates and nitrites. Processed meats have been strongly linked to increased risk of cancer (particularly colorectal cancer), as well as cardiovascular disease, insulin resistance, fatty liver, Type 2 diabetes, and dementia. Research has also found that replacing processed meats with unprocessed poultry and red meat is associated with a lower risk of some chronic diseases, including Type 2 diabetes.

How much meat and poultry should you eat?

There’s no definitive recommendation for an optimal number of daily or weekly servings of meat and poultry. While you may see suggestions to limit red meat (such as no more than 18 ounces of cooked red meat per week, per MD Anderson Cancer Center), your ideal intake comes down to your health risk factors (e.g., blood lipids, heart disease risk, cancer risk) and other sources of saturated fat you may be consuming. Vary your meat intake with fish, eggs, dairy, and plants—and stick to leaner cuts if you’re worried.

Fish and seafood proteins: Salmon, sardines, mackerel, trout, tuna, cod, haddock, tilapia, oysters, clams, mussels

Fish and seafood are a source of high-quality complete protein, with an average of six to seven grams of protein per ounce. Like meat and poultry, marine proteins can be a good source of metabolism-friendly B vitamins (especially B12), iron, zinc, and selenium.

Many types of fish and seafood are also relatively high in iodine, vital for the production of metabolism-regulating thyroid hormone, and choline, essential for brain function, liver function, fat metabolism, and cell membrane formation. Some varieties also contain high levels of long-chain omega-3 fatty acids (EPA and DHA), which curb inflammation and protect against chronic diseases like CVD, and vitamin D, which helps regulate immune function and inflammation, and supports normal cardiovascular function and glucose metabolism.

Cold-water, fatty fish, including salmon, sardines, mackerel, and trout, are top protein picks for supporting metabolic health, as they are the best food source of naturally occurring omega 3s and vitamin D. For example, studies have found that 100 grams (3.5 ounces) of salmon typically contains around 450 IU of vitamin D or 75 percent of the recommended intake, and somewhere between 700 and 1,500 mg of EPA and DHA, far exceeding the intake level at which health benefits are thought to kick in (250 mg per day). Salmon is also a standout for its high levels of the antioxidant astaxanthin, which is responsible for salmon’s pink color and is associated with reduced blood glucose, improved insulin sensitivity, and neuroprotective effects.

Canned tuna can also be a healthy pick, depending on the brand. Typically, canned tuna loses most of its omega-3s during processing, but brands that cook their tuna just once, directly in the can, retain these healthy fats. (We like Wild Planet Skipjack Wild Tuna, which has 32 grams of protein, 582 mg of EPA/DHA, and 320 IU of vitamin D (40 percent of the RDA) per can.)

Despite their relative lack of omega-3s, white fish like haddock, cod, and tilapia, as well as shellfish like oysters, mussels, and clams, are still highly nutrient-dense and should also be included in your seafood rotation. Case in point: Haddock contains the highest concentration of iodine of all seafood, cod is a good source of iodine and choline, oysters contain more zinc per serving than any other food, and tilapia is an excellent source of selenium.

What else to consider

Wild-caught seafood may be a better metabolic choice compared to farmed, given these animals are exposed to a broader range of foods and nutrients and potentially fewer contaminants like polychlorinated biphenyls (PCBs). Some research also suggests that wild-caught salmon is higher in astaxanthin, EPA, and DHA compared to farmed. Lastly, choose low-mercury choices as often as possible, as this heavy metal can contribute to neurological problems and oxidative stress that would negate any metabolic benefits.

How much fish and seafood should you eat?

There’s no definitive recommendation for everyone, but the 2020-2025 Dietary Guidelines for Americans (DGAs) recommends at least eight ounces of seafood per week or two four-ounce (palm-sized) servings for adults. The American Heart Association (AHA) recommends at least two servings of seafood per week, particularly fatty fish, due to the beneficial impact of omega-3s on cardiovascular health. Note that pregnant women should aim for at least eight to 12 ounces (two to three servings) of low-mercury seafood per week, given the importance of the nutrients above in fetal development.

Egg protein

Until the recent price spike due to avian flu, eggs were traditionally an inexpensive source of high-quality complete protein. When used to replace a high-carb breakfast, they can support weight loss and lower blood sugar and insulin. They’re also a potent source of nutrition: One egg has about 6.5 grams of protein, a variety of antioxidant nutrients (vitamin A, vitamin E, lutein, and zeaxanthin), and a good percentage of your recommended intake of metabolism-friendly vitamin B12 (21 percent), selenium (28 percent), iodine (16 percent), vitamin D (8 percent or more), and choline (31-40 percent). Some research suggests that eggs from pasture-raised hens exposed to sunlight and a more varied diet contain higher concentrations of vitamin E, omega-3 fatty acids, and vitamin D compared to eggs from conventionally raised hens.

What else to consider

Eggs are less protein-dense than meat, fish, and some dairy, meaning you need to eat more to get the same amount of protein. For example, to meet the goal of 25 to 30 grams of protein in a meal, you’d have to eat four eggs, which clocks in at 26 grams of protein, 288 calories, 6.5 grams of saturated fat, and more than 800 mg of cholesterol. Comparatively, one cup of 2-percent cottage cheese contains about 24 grams of protein, 183 calories, 2.8 grams saturated fat, and 27 mg of cholesterol. (This is why pairing an egg or two with another protein-dense food source could be a smart way to hit 30+ grams of protein without overdoing it on anything else.)

The higher calories, saturated fat, and cholesterol per gram of protein from eggs versus other animal proteins isn’t necessarily a problem, especially if you don’t have high blood lipids or a history of heart disease. However, people with elevated LDL cholesterol or at higher risk need to be aware of their overall dietary load of saturated fat, which can drive up LDL if consumed in excess. Also, keep in mind: Dietary cholesterol from sources like eggs has little impact on blood cholesterol levels for the average healthy person, but for about 15 to 25 percent of the population, it can more strongly impact cholesterol levels. If you get bloodwork and notice your LDL creeping up after increasing your egg consumption, reduce your intake or opt instead for egg whites, which are cholesterol-free. Remember, the whites are a less nutrient-dense option overall, as most of the vitamins, minerals, and other micronutrients are found in the yolk.

If you want to cap the number of eggs you have in one meal, for whatever reason, consider pairing them with other protein-rich foods:

• Make a scramble with your choice of veggies, two eggs, and ½ cup cottage cheese. Blend the eggs and cottage cheese before cooking for a smoother texture.
• Serve two scrambled eggs alongside ½ cup plain Greek yogurt and berries.
• Serve a fried egg or two atop reheated dinner leftovers, such as roasted veggies and chicken.

How many eggs should you eat?

On the conservative end of the spectrum, some research suggests that in the context of a healthy diet, most people can safely eat up to seven eggs per week (about one per day) without negatively impacting cholesterol and cardiovascular health. But you may be able to eat more. As mentioned, many people don’t experience a rise in cholesterol with increased cholesterol intake.

Dairy proteins: Milk, yogurt, kefir, cottage cheese, some cheeses

Dairy products are another source of high-quality, animal-based, complete protein. Of course, whole milk or full-fat dairy products can also contain a significant amount of saturated fat, so keep this in mind if you’re watching your LDL cholesterol. Depending on the type of dairy, protein content can vary quite a bit, but here are some high-protein picks:

• 2-percent cottage cheese has about 24 grams per cup
• Plain Greek yogurt has 21 grams (full-fat) to 24 grams (low-fat) per cup
• Plain whole-milk kefir has about 10 grams per cup
• Whole cow’s milk has 8 grams per cup, but some ultra-filtered brands have 13 grams per cup

Some harder cheeses are also a relatively good source of protein. Per ounce, Parmesan contains 10 grams of protein, Swiss contains 8 grams, and sharp cheddar and part-skim mozzarella each contain 7 grams. Consider using these as a protein-rich condiment to boost your meal’s overall protein content and flavor (try shaved Parmesan on a salad), or eat them as part of a balanced snack (like a wedge of cheddar with raspberries).

Beyond protein, dairy products can be a good source of nutrients that support energy metabolism, brain health, thyroid health, and the body’s antioxidant status, including B vitamins, vitamins A and D, choline, zinc, and selenium. They’re also a good source of bone-building calcium and blood pressure-regulating potassium. And yogurt, kefir, and cultured cottage cheese contain probiotics, which help increase the diversity of your gut bacteria, and, in turn, reduce inflammation (look for “live and active cultures” on the label). Lastly, like grass-fed beef, dairy products from grass-fed cows may contain significantly higher levels of conjugated linoleic acid (CLA), a fat associated with metabolic benefits.

What else to consider

Dairy—mainly milk—also contains some carbohydrates in the form of lactose. So, compared to other animal protein sources, dairy may contribute to a rise in blood glucose, followed by insulin release to help clear that glucose from the bloodstream. Interestingly, some research suggests that dairy triggers a disproportionately high surge in insulin for the carbs it contains, though it’s unclear why. This potentially harmful effect appears to be strongest for low-fat and fat-free milk, while full-fat milk, fermented forms of dairy (yogurt, kefir, cultured cottage cheese), and low- and full-fat cheeses may have a favorable effect on insulin levels and metabolic health. Full-fat dairy also appears to be less harmful to cardiovascular health than previously thought, though you still want to watch your saturated fat intake if you have elevated cholesterol.

How much dairy should you eat?

The 2020-2025 DGAs recommend that adults consume three cup-equivalent servings of dairy daily, primarily for the calcium content. That said, no protein-specific recommendations exist for dairy. So consider your overall protein needs and vary your dairy intake with a variety of plant proteins and other animal-based proteins for maximum nutrient diversity.

Plant-based proteins: Traditional soy foods, legumes, nuts and seeds, nutritional yeast

While hitting your daily quota with animal proteins is easier, don’t skimp on plants. Most whole and minimally processed plant proteins like edamame, lentils, and hemp seeds also contain fiber, a variety of micronutrients, and phytochemicals with antioxidant effects that work together to support cellular health, curb chronic disease risk, and support healthy aging and longevity.

Fiber, which is unique to plant foods, has been shown to help balance blood sugar, lower insulin resistance, reduce cholesterol, and feed healthy gut bacteria, which, in turn, can help curb inflammation. Magnesium, a mineral abundant in plant proteins like edamame and pumpkin seeds but found in relatively small amounts in animal foods, supports glucose control, insulin sensitivity, and energy metabolism. And polyphenols, a class of phytochemicals found in nuts, seeds, and legumes, help reduce oxidative stress and inflammation, two main drivers of metabolic dysfunction. Plant proteins are also very low in saturated fat, which can support healthy cholesterol levels; and some, like hemp seeds, contain omega-3s in the form of alpha-linolenic acid (ALA). All of which underscores the importance of varying your protein intake.

What else to consider

Broadly, plant protein categories include legumes (beans, peas, lentils), soy foods (edamame, tofu, tempeh), and nuts and seeds—but not all of these plant proteins are created equal.

• Only a few plant proteins are considered complete and contain all nine essential amino acids in sufficient amounts: for example, soy and hemp. Other plants are low in one or more of these amino acids. But, as long as you eat a variety of protein foods daily (whether from just plants or a combo of plants and animal foods), you’ll get the amino acids you need.
• Some higher-protein plants come packaged with a moderate to high amount of carbohydrates (e.g., legumes like lentils, beans, and peas), and others may be a concentrated source of calories and fat (e.g., nuts, seeds, and nut butters). This is not a dealbreaker, but it means these foods aren’t the most efficient source of protein. Pro tip: Always pair legumes with a source of healthy fat to support stable blood sugar.
• Soy foods (tofu, tempeh, edamame), hemp seeds, and nutritional yeast are more dense protein sources and contain fewer carbohydrates per serving. If you are predominantly plant-based, regularly add these to your plate to help meet your goals.

Below are some nutrient-dense plant-protein options to help guide your intake, including some of the most concentrated whole-food or minimally processed sources in their plant category. Many of these are excellent sources of metabolism-friendly micronutrients, too. For example, edamame, pumpkin seeds, and almonds are good sources of magnesium; pumpkin seeds, edamame, and (especially) lentils are high in non-heme iron; pistachios are packed with the antioxidants lutein and zeaxanthin; and nutritional yeast is fortified with a variety of B vitamins.

• Tofu (½ cup): 22 g protein, 181 calories
• Edamame (1 cup): 18 g protein, 188 calories
• Tempeh (½ cup): 17 g protein, 160 calories
• Split red lentils (¾ cup): 18 g protein, 225 calories
• Green peas (1 cup): 8 g protein, 117 calories
• Hemp seeds (3 tablespoons): 10 g protein, 180 calories
• Pumpkin seeds (¼ cup): 9 g protein, 180 calories
• Dry pistachios (¼ cup): 6 g protein, 172 calories
• Whole almonds (¼ cup): 7.5 g protein, 207 calories
• Nutritional yeast (2 tablespoons): 5 g protein, 40 calories

What percent of your protein should be plant protein?

Eat plant proteins liberally. There’s no recommendation or cap on what percentage of your protein, or how many daily or weekly servings, should come from plants. However, the above foods can safely be incorporated into daily meals and snacks.

Protein powders and other processed protein sources

Whole-food protein sources are preferable to protein powders, as they’re naturally packaged with a broader range of metabolism-friendly nutrients (like vitamins, minerals, antioxidants, fiber, healthy fats). That said, if you don’t eat animal products and have a tough time meeting your needs, or if you’re simply busy, high-quality protein powders (like these) are convenient options to add as much as 20 to 30 grams of complete protein to a meal, snack, or post-workout shake. Just avoid having more than one serving a day, as you’ll miss out on more nutritious protein sources. Essential amino acid supplements (like this or this – both vegan), which contain isolated versions of all nine essential amino acids, may also help cover your bases.

What else to consider

When selecting a protein powder—whether it’s whey, casein, egg white, hemp, soy, a plant protein blend, or beef—opt for one with minimal ingredients. Ideally, it should contain just the source of protein (e.g., whey protein isolate, soy protein isolate, hemp protein concentrate). Also, aim to steer clear of those with added sugars, which can spike blood sugar, and avoid artificial sweeteners, which can negatively impact the gut microbiome. To reduce exposure to heavy metals, which have turned up in some protein powders, opt for a product that’s been third-party tested for safety (NSF Certified for Sport is a well-respected seal).

Important to note: Collagen powder is not a complete protein, as it lacks the amino acid tryptophan and is low in the amino acid leucine. Therefore, it could be less effective at stimulating muscle protein synthesis than something like whey or soy. However, it can still be a worthwhile and convenient protein source in the context of a varied diet.

To bolster the protein content of your meals and snacks, try:

• Adding protein powder to a smoothie with berries, greens, and hemp seeds
• Mixing it with Greek yogurt, nuts, and berries
• Blending it into pancake batter
• Stirring it into overnight oats or chia pudding for a filling breakfast
• Use it to make no-bake protein bites

Like protein powders, protein bars can also be handy in a pinch. Still, many varieties contain added sugars, low-quality vegetable and seed oils, and funky additives—and some don’t contain much protein. When choosing a bar, opt for one with 10 to 20 grams of protein, zero added sugars, and a short ingredient list (try one of these).

Finally, highly processed forms of protein, such as popular egg substitutes (like Just Egg) and alternative meats (like Beyond Meat and Impossible Foods products), should be consumed sparingly, if at all, when trying to optimize metabolic health. These food products tend to be an amalgamation of multiple highly processed ingredients, some of which add calories but not much in the way of nutrient value, such as sunflower and canola oils. Additionally, while these food products are technically “plant-based” in that they are not from animals, many lack the range of naturally occurring micronutrients, phytochemicals, healthy fats, and fibers you’d get from eating a variety of whole-food and minimally processed plant proteins. If you’re going to eat one, read the ingredients label to know exactly what you’re getting.

Bottom line

There are so many high-quality protein options to choose from. To efficiently hit your daily protein goals while maximizing nutrient variety and overall metabolic health, remember these basic guidelines:

1. Opt for variety among both animal and plant-based sources (or just plant sources if you follow a vegan diet).
2. Choose whole or minimally protein foods, and don’t rely on convenience products.
3. Be mindful of saturated fats and switch up your animal proteins to contain lean sources or sources rich in healthy fats like omega 3s.
4. Make sure some of your plant protein picks are ones with a more concentrated source of protein.

To recap, here are some of the top sources of protein to include in your diet for metabolic health:

• Eggs
• Lean meat (bison, >90 percent lean ground beef, flank steak, pork tenderloin, lamb chops)
• Poultry (skinless chicken or turkey breasts or thighs, ground chicken or turkey)
• Fatty fish (salmon, sardines, mackerel, trout, skipjack tuna)
• White fish (cod, haddock, tilapia)
• Shellfish (oysters, clams, mussels)
• Fermented dairy (cultured cottage cheese, plain Greek yogurt, plain kefir)
• Cheese (Parmesan, Swiss, sharp cheddar, part-skim mozzarella)
• Whole or traditional soy foods (edamame, tofu, tempeh)
• Legumes (lentils, green peas)
• Nuts and seeds (hemp seeds, pumpkin seeds, pistachios)
• Nutritional yeast
• High-quality protein powders

Track your protein intake and find the best sources for you

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