How junk food could be weakening your body from within

An MRI scan reveals what looks like a richly marbled steak.
But this isn’t food, it’s the thigh muscle of a 62-year-old woman.
Her diet consisted of 87% ultraprocessed foods.
Fine streaks of fat weave through the muscle tissue.
The image highlights how diet can reshape the body in unseen ways.

What her diet looked like

“This participant’s diet was mainly comprised of cold cereals, chocolate candy or candy bars, regular soft drinks or bottled sugary drinks,” said Dr. Zehra Akkaya.
These foods are typical examples of ultraprocessed products.
They are often high in sugar, additives, and refined ingredients.
Such diets are increasingly common worldwide.

Why fat inside muscle matters

Hidden fat within muscle fibers is more than cosmetic.
It can signal deeper health concerns.
This type of fat interferes with how muscles function and repair.
Researchers are now linking it to long-term disease risks.

Ultraprocessed foods and health risks

Ultraprocessed foods are already tied to obesity and weight gain.
They are also linked to cancer, heart disease, and type 2 diabetes.
Mental health effects, including depression, have been noted.
Some studies suggest they may even shorten lifespan.

How common is this diet pattern

More than half of US adults’ calories come from ultraprocessed foods.
Among children, the number rises to 62%.
This makes the issue a widespread public health concern.
The long-term effects are still being uncovered.

Comparing two cases

Another woman in the study consumed about 29% ultraprocessed food.
She also showed fat in her thigh muscles, but far less.
“It was especially concerning because these individuals, scanned at a time when they had no signs of knee osteoarthritis, already showed compromised muscle quality,” Akkaya said.
The contrast highlights the potential impact of diet.

The connection to knee problems

Fat inside muscles weakens them over time.
It blocks proper muscle regeneration and growth.
Weak muscles place more strain on joints.
This is a key factor in knee osteoarthritis.

A growing global issue

Knee osteoarthritis affects nearly 375 million people worldwide.
It was once seen as a disease of older adults.
Now, more than half of new cases occur in people under 55.
Rising obesity rates are believed to be a major driver.

Why thigh muscles are critical

“Thigh muscles are crucial for knee joint stability,” Akkaya explained.
When these muscles lose strength, joint stress increases.
Excess body weight makes the strain even worse.
Strong muscles help protect the knee from damage.

A whole-body effect

Fatty muscle changes don’t stay in one place.
“It’s a systemic process so it’s not just in the thigh,” said Dr. Miriam Bredella.
Other muscles, in the calves, shoulders, and abdomen, can be affected.
This suggests a broader impact on overall health.

Why muscle quality matters

Poor muscle quality leads to weakness.
That weakness can affect recovery from illness or surgery.
“If you are in the hospital, muscle weakness increases your length of stay,” Bredella said.
“It increases surgical complication, tumor recurrence, it is bad.”

What the research found

The study analyzed MRI scans from 615 adults around age 60.
None had knee osteoarthritis at the time.
Those who ate more ultraprocessed food had more fat in their muscles.
“Throughout the study, the more ultraprocessed foods a person consumed, the more intramuscular fat they had in their thigh muscles, regardless of caloric intake,” said Dr. Thomas Link.

What you can do to protect your body

Exercise and diet changes can improve muscle quality.
Low-impact activities like elliptical training and strength exercises are recommended.
Focus on whole, home-cooked foods rather than packaged options.
Swap sugary drinks for water and choose less processed alternatives.
Even small changes can help reduce fat buildup and support stronger muscles.

This article is made and published by Edith Hejberg, who may have used AI in the preparation