A new large-scale study has found no evidence that eating more protein—whether from animals or plants—increases the risk of early death. Surprisingly, people who consumed higher amounts of animal protein actually showed a slightly lower risk of dying from cancer.

Published in Applied Physiology, Nutrition, and Metabolism on July 16, the research helps clarify long-standing confusion over whether diets high in meat, dairy, or eggs could be harmful to long-term health.

How the Study Was Done

Researchers analyzed data from over 15,000 U.S. adults who participated in the Third National Health and Nutrition Examination Survey (NHANES III) between 1988 and 1994. The participants, aged 19 and older, were followed for 12 years to track deaths from all causes, including cancer and heart disease.

To ensure accuracy, the team used a multivariate Markov Chain Monte Carlo (MCMC) model, a sophisticated method that estimates a person’s usual nutrient intake, taking into account daily dietary changes and common reporting errors.

The study also looked at insulin-like growth factor 1 (IGF-1), a hormone sometimes linked to cancer risk, to explore whether it played a role in mortality related to protein intake.

Protein consumption was categorized as either:

• Animal protein (from meat, dairy, eggs)

• Plant protein (from legumes, nuts, grains, and seeds)

What They Found

The findings revealed no increased risk of death associated with eating more protein, regardless of the source. This applied to:

• Overall mortality

• Cancer-related deaths

• Cardiovascular deaths

In fact, individuals who consumed more animal protein had a slightly reduced chance of dying from cancer. Including IGF-1 data in the analysis didn’t change the results, suggesting that previously suspected links between the hormone and mortality may not hold up under closer scrutiny.

Age didn’t appear to impact the outcomes either. People under 65, over 65, and those in the 50–65 age group all showed no heightened risk tied to higher protein intake.

The researchers believe this study may offer more reliable insights than previous ones, thanks to more accurate tracking and advanced statistical modeling.

Expert Opinions

Health writer Avery Zenker, who was not involved in the study, said the results are consistent with current dietary guidelines.

“Consuming more than the minimum recommendation of 0.8 grams of protein per kilogram of body weight didn’t shorten lifespan,” Zenker told Healthline. “Higher intake levels still fell within the safe range of 10–35% of daily calories from protein.”

She noted, however, that quality matters. “While protein itself isn’t harmful, not all sources are equal. For example, processed meats are still associated with negative health outcomes like heart disease and cancer,” she explained.

Zenker also pointed out that protein-rich foods contain more than just protein. “Other nutrients—like fats, vitamins, and minerals—also impact health,” she added.

Different People, Different Needs

Maura Donovan, a board-certified sports dietitian at Thorne, emphasized that protein needs vary depending on age, activity level, and overall health.

• Older adults benefit from more protein to maintain muscle mass and function.

• Athletes require higher amounts to support training and recovery.

• Those recovering from illness or surgery often need increased protein to help the body heal.

• Vegetarians and vegans should combine plant-based protein sources to get all essential amino acids.

“There’s no universal rule for protein intake,” Donovan said. “It’s best to tailor your diet to your personal goals and health needs—ideally with the help of a registered dietitian.”

Key Takeaway

This comprehensive study suggests that eating more protein doesn’t shorten your life—and in some cases, it may even help protect it, particularly when it comes to cancer risk. Whether your protein comes from plants or animals, the evidence supports that moderate to high intake within recommended levels is safe for most people.

As always, the focus should be on balanced, nutrient-rich eating and choosing high-quality, minimally processed foods whenever possible.