A recent study has revealed a concerning link between diets rich in ultra-processed foods and the accumulation of fat deposits in the muscles, particularly in the thighs. This finding has significant implications for joint health, especially in the context of knee osteoarthritis. The study highlights how dietary habits can influence muscle composition, leading to weakened muscles and increased risk of cartilage damage in the knee joints.
The Connection Between Diet and Intramuscular Fat Deposits
According to the study, individuals who consumed large amounts of ultra-processed foods exhibited a higher concentration of intramuscular fat deposits in their thighs. These deposits appeared regardless of calorie intake or physical activity levels, suggesting that the quality of the diet plays a critical role in muscle health.
The study’s findings were unveiled at the Annual Meeting of the Radiological Society of North America (RSNA) in December 2024, based on imaging data from 666 participants in the Osteoarthritis Initiative. The participants, aged around 60 years on average, had a mean body mass index (BMI) of 27. None of them had developed osteoarthritis at the time of the study. However, imaging revealed fatty degeneration in their muscles, where fat replaced muscle fibers—a process visible through MRI scans.
Dr. Zehra Akkaya, a radiologist at Ankara University and one of the study’s authors, explained that these changes in muscle composition weaken the muscles responsible for protecting cartilage in the knee joints. This weakening increases the likelihood of cartilage damage and subsequent osteoarthritis.
What Are Ultra-Processed Foods?
Ultra-processed foods are industrially manufactured products designed for convenience, taste, and affordability. Unfortunately, their nutritional value is often compromised. These foods typically contain five or more ingredients, including high levels of sugar, unhealthy fats, and various additives such as preservatives, flavor enhancers, and food colorings.
Common examples of ultra-processed foods include:
- Sugary beverages like sodas and packaged juices
- Processed snacks such as chips and cookies
- Packaged baked goods
- Ready-to-eat meals and fast food
- Highly refined cereals and bread
The high sugar and fat content, along with additives, make ultra-processed foods a significant contributor to inflammation and various health issues, including insulin resistance, diabetes, and now, as this study suggests, muscle degeneration.
How Ultra-Processed Foods Impact Muscle Health
Experts hypothesize that ultra-processed foods contribute to increased visceral fat—the dangerous type of fat that surrounds internal organs and is linked to inflammation. Dr. Gowri Reddy Rocco, founder of Optimum Wellness and Longevity, noted that these foods likely exacerbate insulin resistance and lead to the replacement of muscle tissue with fat.
Dr. Paul Arciero, a professor at Skidmore College, elaborated that the sugar, refined grains, and fats in ultra-processed foods trigger the release of pro-inflammatory molecules like glucose, insulin, and cytokines. These molecules not only contribute to systemic inflammation but also increase muscle pain and fatigue. Over time, this leads to weakened muscles incapable of adequately supporting the joints.
Muscle Fat Deposits and Osteoarthritis
Osteoarthritis is the most prevalent form of arthritis, characterized by chronic inflammation and the gradual deterioration of cartilage. Cartilage acts as a cushion within joints, protecting bones from grinding against each other. Once this cartilage begins to break down, joint pain and stiffness develop.
Muscle health is crucial for joint stability. Strong muscles absorb impact and reduce the strain on joints during movement. However, when thigh muscles are infiltrated with fat, they lose strength and the ability to protect the cartilage effectively. This increases the risk of osteoarthritis progression.
According to Dr. Rocco, muscle replacement by fat makes the muscles weaker, regardless of exercise or caloric intake. This deterioration underscores the importance of maintaining a healthy diet to support muscle and joint health.
Can Muscle Damage Be Reversed?
The good news is that diet modification can help reverse some of the damage caused by poor eating habits. By reducing the intake of ultra-processed foods and adopting a nutrient-dense diet, individuals can:
- Decrease intramuscular fat deposits
- Strengthen weakened muscles
- Improve cartilage health and joint function
While existing joint damage cannot be undone, these changes can slow or halt the progression of osteoarthritis and reduce associated pain.
Preventing Knee Osteoarthritis: Practical Strategies
To minimize the risk of knee osteoarthritis, experts recommend focusing on lifestyle changes, as genetic factors play only a minor role. Here are some actionable strategies:
- Adopt a Balanced Diet
Shift away from ultra-processed foods and prioritize whole, unprocessed foods rich in nutrients. Include plenty of:
- Lean proteins, such as chicken, fish, and legumes
- Whole grains, like quinoa and brown rice
- Healthy fats from sources like avocados, nuts, and olive oil
- Fresh fruits and vegetables
These foods reduce inflammation and provide the nutrients needed for muscle repair and maintenance.
- Maintain a Healthy Weight
Excess body weight puts additional stress on joints, especially the knees. Losing even a small amount of weight can significantly reduce this strain and improve joint health.
- Stay Active
Regular exercise strengthens muscles, improves joint stability, and promotes overall health. Focus on low-impact activities such as swimming, cycling, or walking to minimize joint strain.
- Wear Supportive Footwear
Proper footwear helps distribute body weight evenly and supports healthy joint alignment, reducing the risk of knee osteoarthritis.
- Be Mindful of Repetitive Movements
Avoid excessive wear and tear on the joints by varying physical activities and using proper techniques during exercise or repetitive tasks.
- Monitor Hormonal Changes
Women going through menopause should pay extra attention to joint health, as hormonal changes can increase the risk of osteoarthritis.
Detecting Intramuscular Fat Deposits
For individuals concerned about their risk of osteoarthritis, healthcare professionals can assess intramuscular fat deposits through various methods:
- Circumference Measurements: Simple tools to estimate fat distribution.
- Skinfold Testing: Measures subcutaneous fat thickness.
- Bioelectrical Impedance Analysis (BIA): Analyzes body composition, including fat and muscle percentages.
- Dual X-ray Absorptiometry (iDXA): Provides precise data on fat and muscle distribution but is more expensive and specialized.
Early detection of muscle degeneration allows for timely intervention, emphasizing the importance of regular health check-ups.
A Holistic Approach to Health
Preventing osteoarthritis and maintaining overall health require a holistic approach. Nutrition plays a central role, but it must be complemented by other healthy habits.
By avoiding ultra-processed foods and embracing a lifestyle focused on balanced nutrition, physical activity, and weight management, individuals can significantly reduce their risk of developing knee osteoarthritis and other chronic conditions. The study serves as a wake-up call to prioritize dietary choices and underscores the powerful impact of food on our muscles, joints, and overall well-being.