Debunking the Top 3 Protein Myths

By Professor Stu Phillips

Takeaway points

• Eating more protein does not harm healthy kidneys.

• Protein strengthens bones rather than weakening them.

• Higher protein intakes do not shorten lifespan and may support healthy aging.

Introduction

Protein is one of the most talked-about nutrients. Athletes, older adults, and even children are told that they need it for strong muscles, healthy bones, and improved recovery from exercise. But many myths about protein still confuse. Let’s take a closer look at three common myths and see what the science actually shows.

Myth 1: Eating more protein will cause your kidneys to fail

Many people believe that consuming a high amount of protein is detrimental to the kidneys. This idea originated from studies on individuals who already had kidney disease. For them, reducing protein intake can sometimes be beneficial. However, for healthy individuals, research indicates no harm.

A large review of more than 1,300 adults found that consuming more protein, even up to twice the current recommended amount, did not harm kidney function. Another review agreed, showing that while protein can cause the kidneys to work a little harder, this is a normal and safe response, not a sign of kidney damage. For healthy adults, consuming more protein of between 1-3g per kg body weight, does not increase the risk of kidney disease.

Myth 2: Protein makes bones brittle and easier to break

Some people believe that protein weakens bones because it can increase calcium excretion in the urine. But newer, stronger studies show the opposite. Protein is actually a building block of bone itself, making up about half of bone volume.

A comprehensive analysis of studies found that individuals who consumed more protein had slightly higher bone density in their spines and tended to lose less bone over time. Importantly, there is no evidence that eating more protein increases the risk of hip fractures or other serious breaks. When protein is eaten along with calcium and vitamin D, the results for bone health are even better.

So, instead of harming bones, protein supports them.

Myth 3: Eating more protein will shorten your life

Some headlines have claimed that high protein intake, especially from animal foods, may raise the risk of cancer or shorten life. These claims originated from a single older study; however, more recent and larger analyses do not support this.

A 2025 study using data from nearly 16,000 U.S. adults found no link between usual protein intake and higher risk of death from heart disease, cancer, or any cause. In fact, people who ate normal amounts of protein lived just as long, and in some cases, animal protein was even linked to a lower risk of cancer-related death. Other research indicates that protein may actually support healthy aging by helping to preserve muscle mass as we age.

The latest evidence suggests that protein, whether derived from plants or animals, is not detrimental to longevity.

The Takeaway

Protein does not harm healthy kidneys, it does not weaken bones, and it does not shorten your life. On the contrary, protein is essential for maintaining muscles, bones and promoting healthy aging. The real concern for many people is not eating too much protein, but rather ensuring they get enough, especially as they age or if they exercise frequently.

References

• Devries MC, Phillips SM et al., 2018. Changes in Kidney Function Do Not Differ between Healthy Adults Consuming Higher- Compared with Lower- or Normal-Protein Diets: A Systematic Review and Meta-Analysis. J Nutr.

• Van Elswyk ME, Weatherford CA, McNeill SH.2018. A Systematic Review of Renal Health in Healthy Individuals Associated with Protein Intake above the US Recommended Daily Allowance in Randomized Controlled Trials and Observational Studies. Adv Nutr.

• Shams-White MM, Chung M, Du M et al. 2017. Dietary protein and bone health: a systematic review and meta-analysis from the National Osteoporosis Foundation. Am J Clin Nutr.

• Papanikolaou Y, Phillips S, Fulgoni V, 3rd. 2025.Animal and plant protein usual intakes are not adversely associated with all-cause, cardiovascular disease-, or cancer-related mortality risk: an NHANES III analysis. Appl Physiol Nutr Metab.

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