More protein doesn’t give you more muscle… experts separate science from marketing – and reveal what really works

Today’s supermarket shelves are stocked with protein-fortified cereal, pasta, chips, pretzels, coffee, bread and even protein-fortified Pop-Tarts.

When a breakfast pastry best known for its sweetness and convenience is marketed as a protein source, it’s clear that food companies are capitalizing on consumers’ growing interest in protein.

Although there is good science behind much of the current enthusiasm for protein, many people already get adequate amounts of protein in their diets.

That’s how it is important to separate the marketing push to add protein to everything from what is really needed for good health.

What are proteins?

Along with carbohydrates and fats, protein is one of the three macronutrients that you must eat in sufficient quantities for your body to function.

Carbohydrates and fats are your main energy sources. Although protein can also be used for energy, its main purpose is to build and repair the body.

Proteins are needed to build and maintain muscle. This includes skeletal muscle, the muscles that keep your heart beating, the muscles that push food through your stomach and intestines, and the muscles that open your airways for breathing.

But muscles aren’t the only part of the body that needs protein. Proteins are also important for the functioning of your nervous system, immune system, skin, hormones and other essential components.

So protein is not just ‘muscle food’. It is needed throughout the body, even though the marketing of protein foods focuses on the muscles.

What are amino acids?

Proteins are made of amino acids, of which there are 20 types. It is the combination and number of amino acids, as well as the shapes of the proteins they create, that give proteins different roles in the body.

Your body obtains amino acids by digesting the proteins you eat and breaking them down into these individual building blocks.

How well your body absorbs amino acids and makes them available for use is affected by many factors, including the protein source and cooking.

Animal proteins are generally more digestible than vegetable proteins, and cooking generally improves protein digestibility.

Of the twenty different amino acids in proteins, nine are considered essential because the human body cannot produce them directly and must obtain them from the diet. Most protein-containing foods contain most of these essential amino acids, but some foods are low in one or more of them.

Animal proteins, such as eggs, dairy, fish, poultry and lean meats, are good sources of the essential amino acids. Most protein-rich plant foods, such as most beans, nuts and rice, are low in one or more essential amino acids. Soybeans are an exception and offer a complete composition of essential amino acids.

Medical professionals recommend eating a variety of protein sources, including some complete ones, to ensure you get all the essential amino acids. Eating a mixture of protein-rich plant foods can overcome deficiencies in a particular plant food.

Protein powders, often used as supplements, vary in their essential amino acid content and composition. Compared to animal-based powders, plant-based powders tend to have lower levels of one or more essential amino acids and lower protein levels overall.

How much protein do you need?

There is little scientific debate that dietary protein is critical to good health. A more difficult calculation is how much protein you need.

An often cited standard is the federal recommended dietary allowance (RDA). In January 2026, the US government increased the RDA for dietary protein for adults from 0.8 grams per kilogram of body weight to 1.2 to 1.6 grams per kilogram.

For a 150-pound person, this nearly doubles the recommendation from 54 grams to 80 to 110 grams per day. Some experts have interpreted this update as a focus on optimizing health, as opposed to ensuring adequate protein intake to prevent deficiencies.

However, the new federal guidelines are not without controversy. How much protein a given person needs is a complex question that depends on individual health goals, age, gender, activity level, medical history and other factors. Consultation with a medical provider or licensed nutritionist can help individualize protein goals in the diet.

Many experts agree that the average, healthy American adult already gets enough protein. Although most healthy adults can tolerate a moderately high protein intake, too much protein can cause health problems such as kidney damage and digestive problems.

Companies market high-protein diets to encourage weight loss, because consuming more protein tends to increase feelings of satiety. A 2026 study identified a link between the amino acid leucine and appetite suppression via a connection between the gut and the brain.

That said, while suppressing appetite can aid weight loss, it can also reduce the consumption of calories from fruits, vegetables, beans and whole grains that provide fiber, vitamins and other important nutrients.

What about protein powders and supplements?

Protein powders are a $20 billion industry, and their popularity reflects both the idea that dietary protein can support muscle growth and reduce muscle loss and how lucrative protein supplements can be.

For people with a low appetite or for those who have difficulty meeting dietary protein recommendations, high-protein foods can be a helpful way to increase protein intake.

This may include those taking GLP-1 weight loss medications, which can reduce appetite and make it harder to eat enough protein and other nutrients.

But while a protein shake can provide essential amino acids, it does not provide the broader nutritional benefits of protein-rich foods, such as fish, beans, nuts, yogurt and soy products.

In addition, protein-enriched packaged foods may contain increased sugar, salt or saturated fat content. A protein bar may be closer to a bar with better branding.

For these reasons, medical organizations recommend consuming well-planned combinations of protein sources from non-packaged foods.

Building muscle requires more than just protein

In addition to bodybuilding, science has increased society’s appreciation of the importance of dietary protein in combating muscle loss due to aging, weight loss or injury.

Some experts don’t think doubling your protein intake is as important for building muscle as resistance training, a type of exercise that creates force and tension on the muscles to signal the body to repair and grow more muscle.

This is different from endurance training which improves aerobic capacity.

A 2021 clinical trial found that older adults only saw improved muscle size, strength and function when high-protein diets were combined with heavy resistance training.

Eating more protein alone will not build muscle, because the crucial molecular pathways for muscle growth and strength require repeated heavy forces on the muscles.

Challenging your muscles with repetitive training and increasingly heavier weights encourages the muscles to adapt by becoming larger and better able to produce force. The nervous system also adapts and becomes better able to activate and coordinate muscle movements.

Resistance training is also key to preventing muscle loss associated with weight loss caused by GLP-1 medications, aging and injury recovery. The key takeaway is that dietary protein and resistance training work together to promote muscle growth and maintain strength.

Protein in everything: science versus sales pitch

So, is the protein craze based on real science, or is it a fad?

It’s both. The science is clear: Dietary protein supports muscle maintenance, growth, recovery and recovery from injuries, fullness and weight regulation, and healthy aging. The craze is the idea that any food with added protein is automatically better – and that you can always benefit from more protein.

Protein deserves attention. But marketing protein-fortified food products is not a shortcut to a quality diet that provides a complete source of amino acids from nutritious foods.

This article is adapted from The Conversation, a nonprofit news organization dedicated to sharing the knowledge of experts. It was written by Linda M Boland, professor of biology at the University of Richmond. It was edited by Alexa Lardieri, the US health editor at the Daily Mail.