In recent years, protein has emerged as a dominant theme in nutrition and fitness conversations, fueled by social-media trends and aggressive marketing that promote superhigh-protein diets. From snack bars and yogurts to ice cream and even bottled water, food manufacturers have found myriad ways to add extra protein to everyday products, tapping into a booming market worth tens of billions of dollars. Influencers and some health professionals often tout high-protein regimens as secrets to building strength, enhancing longevity, and optimizing health. Yet, despite protein’s undeniable importance, the question of how much protein people truly need remains complex and contentious.
Official dietary guidelines typically recommend around 0.8 grams of protein per kilogram of body weight daily. For a 70-kilogram adult, this equates to roughly 56 grams of protein, or about 250 grams of cooked chicken breast. However, wellness circles frequently encourage consuming more than double this amount, sometimes advocating for intake levels above 2 grams per kilogram. Many scientists find themselves in a middle ground, concerned that some popular advice is overstated and unsupported by evidence.
Katherine Black, an exercise nutritionist at the University of Otago in New Zealand, expresses frustration with the protein hype propagated on social media. She notes that while protein needs do vary between individuals and across life stages, there is no solid scientific backing for the extreme intakes often promoted online. The pervasive obsession with protein powders and protein fortification in everyday foods can overshadow the nuanced reality that people should focus on balanced diets that meet their actual needs.
Guidance from health authorities remains crucial for helping the public navigate protein consumption. The upcoming Dietary Guidelines for Americans, expected by the end of 2025, may update protein recommendations in light of new research. Understanding how protein requirements have been estimated helps contextualize these guidelines. Since the 1940s, the nitrogen-balance method has been the cornerstone of determining protein needs. Because protein is the only major macronutrient containing nitrogen, measuring nitrogen intake and excretion allows researchers to estimate how much protein the body uses.
The Recommended Dietary Allowance (RDA) for protein, set by the US National Academies of Sciences, Engineering, and Medicine, currently stands at 0.8 grams per kilogram per day. This level is intended to cover the needs of 97–98% of healthy individuals. Similar benchmarks exist globally, with many authorities recommending comparable or slightly higher amounts.
However, many experts argue that the RDA represents a minimum threshold rather than an optimal target. Donald Layman, a nutrition researcher at the University of Illinois Urbana–Champaign, highlights that consuming between 1.2 and 1.6 grams of protein per kilogram daily may better support overall health, particularly for certain populations. Older adults, for example, often face muscle loss and declining appetite, making adequate protein intake critical for preserving lean mass. Research supports this: in one observational study of adults aged 70 to 79, those consuming about 1.1 grams per kilogram lost 40% less muscle mass over three years than those eating roughly 0.7 grams per kilogram.
Similarly, athletes and individuals engaged in resistance training can benefit from increased protein. A 2017 systematic review found that protein supplementation improved muscle gain and strength among those performing weightlifting exercises, though intakes above 1.6 grams per kilogram did not yield additional gains. For most healthy adults, exceeding this level offers little benefit and may be inefficient, as the body becomes adept at excreting excess protein.
Despite this evidence, some fitness influencers advocate for consuming around 2.2 grams per kilogram or more—levels considered unnecessary for the majority of people. While such high intakes generally pose no harm for individuals with normal kidney function, they do represent an inefficient use of dietary protein. Nicholas Burd, another researcher at the University of Illinois, notes that the protein craze has been largely driven by marketing rather than scientific necessity, with the food industry capitalizing on the popular belief that more protein is always better.
Adding complexity to protein recommendations is the fact that not all proteins are equal in quality. Proteins are composed of amino acids, of which 20 are essential for human health. Nine of these amino acids must be obtained from the diet because the body cannot synthesize them. Animal-based proteins generally contain all essential amino acids in proportions aligned with human requirements, making them “complete” proteins. Plant proteins, in contrast, often lack some essential amino acids or contain them