Study Links Processed Foods to Thigh Fat Gain—Regardless of Calories

A recent study reveals that processed foods like cereal can increase thigh fat, regardless of your total daily calorie intake.

Researchers from the University of California, San Francisco’s Department of Radiology and Biomedical Imaging presented these eye-opening findings on December 4 at the annual North American Radiological Society meeting in Chicago.

The team analyzed data from 666 participants in the U.S. Osteoarthritis Initiative study, exploring the connection between ultra-processed food consumption and fat buildup in thigh muscles.

With an average BMI of 27, the study subjects were overweight, and a whopping 40% of their diet consisted of ultra-processed foods.

The more ultra-processed foods people eat, the more fat accumulates in their thigh muscles. Shockingly, this held regardless of calorie intake, BMI, socioeconomic status, or physical activity. Even seemingly innocent instant meals were culprits in increasing thigh fat. These dietary choices impacted muscle quality, no matter how much people exercised.

Fat accumulating around the thighs increases the risk of knee osteoarthritis. This painful condition can make simple activities like running, climbing stairs, or kneeling a real struggle.

Lead author Dr. Zehra Akkaya highlighted that this groundbreaking study is the first to utilize MRI imaging to examine the impact of diet quality, particularly the consumption of ultra-processed foods, on fat accumulation in thigh muscles.

So, what exactly are considered ultra-processed foods? These foods have been transformed through multiple processing steps and are loaded with chemical additives, colorings, and sweeteners. Your favorite cereals, frozen pizzas, sodas, and even margarine fall into this category—basically, anything with a long shelf life that’s quick and easy to eat.

These foods are often packed with additives, emulsifiers, and high sugar, fat, salt, and carbs. The result? Intense flavors light up your brain’s reward system, making it nearly impossible to stop munching.

Dr. Akkaya warned that consuming ultra-processed foods is associated with increased thigh muscle fat, even for those not at risk for knee osteoarthritis. She emphasized that managing arthritis early and preventing obesity hinges on maintaining a healthy diet and exercising regularly.