Ultraprocessed Foods Linked to Increased Knee Osteoarthritis Risk

New study finds connection between diet and muscle fat buildup that can lead to knee problems.

Apr. 17, 2026 at 8:36pm by

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A new study from researchers at the University of California, San Francisco (UCSF) has found a link between consuming high amounts of ultraprocessed foods and an increased risk of developing knee osteoarthritis, a degenerative 'wear-and-tear' condition. The study analyzed data from 615 individuals and found that those who consumed about 41% of their daily food from ultraprocessed sources had higher amounts of intramuscular fat in their thighs, which can increase the risk of knee osteoarthritis regardless of a person's weight or exercise habits.

Why it matters

Knee osteoarthritis is one of the largest non-cancer-related healthcare costs in the United States and around the world, and it is highly linked to obesity and unhealthy lifestyle choices. This new research suggests that diet, specifically the consumption of ultraprocessed foods, may play a direct role in the development of this debilitating condition.

The details

The research team analyzed data from the Osteoarthritis Initiative, a large, long-term public research project focused on the condition. Through non-enhanced MRI scans, they looked for degeneration marked by streaks of fat replacing healthy muscle fibers in the thigh. This fat buildup was found to be true regardless of a person's total caloric intake, their weight, or how much they exercised. Even if someone was 'thin' or active, if their diet was primarily composed of ultraprocessed foods, muscle quality and knee health could still be at risk.

  • The study analyzed data from the Osteoarthritis Initiative, an ongoing long-term research project.

The players

Zehra Akkaya, MD

A researcher at the University of California, San Francisco (UCSF) and the lead author of the study.

Osteoarthritis Initiative

A large, long-term public research project focused on knee osteoarthritis.

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What they’re saying

“Over the past decades, in parallel to the rising prevalences of obesity and knee osteoarthritis, the use of natural ingredients in our diets has steadily diminished.”

— Zehra Akkaya, MD, Researcher, University of California, San Francisco

“It constitutes one of the largest non-cancer-related healthcare costs in the United States and around the world. It is highly linked to obesity and unhealthy lifestyle choices.”

— Zehra Akkaya, MD, Researcher, University of California, San Francisco

What’s next

The researchers noted that while the study showed a clear link between ultraprocessed foods and muscle fat buildup, it could not definitively prove that the food caused the fat buildup, only that they happened at the same time. Further research is needed to establish a direct causal relationship.

The takeaway

This study highlights the importance of diet quality, not just quantity, when it comes to maintaining healthy joints and muscles. Reducing ultraprocessed food consumption may help preserve muscle quality and alleviate the burden of knee osteoarthritis, a debilitating condition that affects millions.