Ultra-Processed Foods Linked to More Fat in Muscles, Osteoarthritis: Study

Research shows that more fat in thigh muscle resulting from a diet high in ultra-processed foods raises knee osteoarthritis risk.

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Ultra-processed foods are associated with more fat stored inside thigh muscles, regardless of caloric intake or physical activity levels, according to a study presented on Dec. 4 at the annual meeting of the Radiological Society of North America (RSNA).

Scientists at the University of California–San Francisco (UCSF) found that diets heavy in ultra-processed foods, such as chips, cookies, and pre-cooked frozen dinners, are linked to increased fat deposits within thigh muscles, potentially raising the risk of knee osteoarthritis.

Despite expert recommendations advocating diets rich in natural and minimally processed ingredients, many people still eat many ultra-processed foods that are industrially manufactured, artificially flavored, and chemically altered. Common examples of these foods include breakfast cereals, packaged snacks, hot dogs, soft drinks, and ready-to-eat meals. Such options tend to be both appealing and convenient, but they often contain unhealthy combinations of sugar, fat, salt, and carbohydrates, which can influence the brain’s reward system and make it difficult to stop eating.

Weaker Thigh Muscles Associate With Knee OA

“The novelty of this study is that it investigates the impact of diet quality, specifically the role of ultra-processed foods in relation to intramuscular fat in the thigh muscles assessed by MRI,” study author Dr. Zehra Akkaya from the Department of Radiology and Biomedical Imaging at UCSF said in a statement.

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The new research also represents the first imaging study examining the relationship between MRI-based skeletal muscle quality and dietary quality.

The study analyzed data from 666 individuals involved in the Osteoarthritis Initiative, a nationwide research project sponsored by the National Institutes of Health aimed at preventing and treating knee osteoarthritis (OA). The average age of participants was 60 years, with an average body mass index (BMI) of 27.

Akkaya told The Epoch Times that increased intramuscular fat in the thigh muscles indicates that the normal healthy muscle elements are replaced by fat tissue, resulting in poorer muscle quality and weaker muscles.

“Poor thigh muscle function, decreased muscle size or quality are associated with knee osteoarthritis since thigh muscles are crucially important in biomechanical stability of the knee joint,” Akkaya said.

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“Compared to controls, quadriceps, hamstrings, and hip muscles are significantly impaired in patients with knee osteoarthritis, which is linked to the great functional decline and disability these patients suffer.”

She noted that muscle strengthening exercises are recommended as one of the first-line treatments to control pain and reduce disability related to knee OA.

Notably, approximately 40 percent of the foods the participants consumed in the past year were ultra-processed.

The results indicated a correlation between higher consumption of ultra-processed foods and increased intramuscular fat in the thigh muscles.

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Akkaya said that in her current research, “we have shown a link between diet quality and thigh muscle quality.” Specifically, she added, the more ultra-processed food people ate, the more fatty changes within the muscles, as observed by MRI.

“Our results indicate that not just the total caloric content, but also the quality of the diet, meaning what actually a person eats, could be quite important in the efforts to reduce the overall burden of knee osteoarthritis,” Akkaya said.

Lifestyle Factors and Disease Prevention

Akkaya noted the significance of addressing modifiable lifestyle factors, particularly preventing obesity through a healthy, balanced diet and regular exercise.

“Osteoarthritis is an increasingly prevalent and costly global health issue,” Akkaya said in the statement. “It is the largest contributor to non-cancer related health care costs in the U.S. and around the world. Since this condition is highly linked to obesity and unhealthy lifestyle choices, there are potential avenues for lifestyle modification and disease management.”

According to Akkaya, the study’s exploration into how ultra-processed food consumption affects muscle composition provides valuable insights into dietary influences on muscle health. “Understanding this relationship could have important clinical implications, as it offers a new perspective on how diet quality affects musculoskeletal health,” she noted.