Key Takeaways

• High consumption of ultra-processed foods is linked to poorer muscle quality.
• MRI scans show increased fat accumulation in thigh muscles among high consumers.
• This effect occurs regardless of calorie intake, BMI, or physical activity.
• Poor muscle quality is associated with reduced mobility and higher osteoarthritis risk.
• Cutting back on ultra-processed foods may help preserve muscle function and overall health.

Introduction: Why Muscle Health Matters More Than You Think

When we think about diet and health, weight and heart disease often take center stage. However, emerging research suggests that diet also plays a crucial role in muscle quality, which directly impacts strength, mobility, and long-term independence.

A new study published in Radiology provides compelling evidence that diets high in ultra-processed foods may negatively affect muscle health—even in ways not visible on the scale.

What the Study Examined

The study analyzed data from the Osteoarthritis Initiative, collected between 2004 and 2015, involving 615 adults at risk for knee osteoarthritis.

Participant Overview

• 340 women and 275 men
• Average age: ~60 years
• Ultra-processed foods made up ~40% of daily intake
• 65% overweight, 25% obese

Researchers used MRI imaging to assess muscle composition, offering a detailed look at how diet influences muscle structure.

Key Findings: Ultra-Processed Foods and Muscle Fat

The study found that individuals who consumed higher amounts of ultra-processed foods had significantly more fat stored within their thigh muscles.

Importantly, this association remained even after adjusting for:

• Body mass index (BMI)
• Total calorie intake
• Physical activity levels

This indicates that diet quality plays a direct role in muscle health, independent of other lifestyle factors.

What Is Intramuscular Fat—and Why Does It Matter?

Intramuscular fat refers to fat stored within muscle tissue. While some level is normal, excessive accumulation is linked to:

• Reduced muscle strength
• Poor physical performance
• Increased risk of osteoarthritis
• Declining mobility with age

In essence, higher muscle fat can mean weaker, less efficient muscles, even in individuals who appear otherwise healthy.

What Are Ultra-Processed Foods?

Ultra-processed foods are industrial formulations typically made with additives and minimal whole ingredients. Common examples include:

• Sugary beverages
• Packaged snacks
• Ready-to-eat meals
• Breakfast cereals

These foods are highly prevalent, accounting for over 50% of calorie intake in the United States.

The Broader Health Impact of Ultra-Processed Foods

This study adds to a growing body of evidence linking ultra-processed foods to serious health risks, such as:

• Cardiovascular disease
• Coronary heart disease
• Certain cancers
• Increased mortality risk

Now, reduced muscle quality can be added to that list—highlighting another reason to rethink dietary habits.

Why This Study Is Important

According to lead author Dr. Zehra Akkaya from the University of California, San Francisco, this is the first study to use MRI imaging to directly link diet with muscle quality.

This advanced approach provides deeper insight into how food affects the body beyond traditional metrics like weight or BMI.

Practical Tips to Improve Muscle Health Through Diet

To support better muscle quality, consider the following:

1. Reduce Ultra-Processed Foods

Limit intake of packaged and highly refined products.

2. Focus on Whole Foods

Incorporate:

• Fresh vegetables and fruits
• Lean proteins
• Whole grains
• Healthy fats

3. Balance Diet and Exercise

While physical activity is essential, this study shows that diet quality is equally important.

Conclusion: Diet Quality Is Key to Stronger Muscles

This research underscores a critical message:
Your diet affects not just your weight, but the internal health and function of your muscles.

As we age, maintaining muscle strength becomes essential for independence and quality of life. Reducing ultra-processed food intake may be a powerful step toward preserving both.

References

1. Akkaya, Z., et al. (2026). Association Between Ultra-Processed Food Consumption and MRI-Based Muscle Quality. Radiology.
2. Osteoarthritis Initiative (OAI) Database (2004–2015).
3. Monteiro, C. A., et al. (2019). Ultra-processed foods: what they are and how to identify them. Public Health Nutrition.
4. Srour, B., et al. (2019). Ultra-processed food intake and risk of cardiovascular disease. BMJ.
5. Fiolet, T., et al. (2018). Consumption of ultra-processed foods and cancer risk. BMJ.