10-Pound Weight Loss Cuts Knee Force by 40 Pounds Per Step, Expert Says

For every 10 pounds lost, the force exerted on the knee drops by 40 pounds with each step, according to Dr. Abby Cheng, an orthopedic surgeon and physiatrist at Washington University School of Medicine in St. Louis.

What knee osteoarthritis does to joint function

Knee osteoarthritis develops as cartilage between the bones of the joint deteriorates over time. This tissue normally enables smooth motion while absorbing shock and shielding the joint. As it thins, pain, stiffness, and functional limitations may appear — and often progress.

“Osteoarthritis can cause knee pain and stiffness, which can negatively impact a person’s activity level, risk of falling, mood and general quality of life,” Cheng said.

Risk factors beyond age

Osteoarthritis affects more than 30 million adults in the U.S., with the knee being the most frequently involved joint. Although incidence rises with age, approximately half of all diagnosed cases occur among working-age individuals.

Cheng identified several established risk factors: weak leg muscles; overweight or obesity; female sex; older age; prior knee injury; and family history of osteoarthritis.

How lifestyle habits influence disease progression

Healthy behaviors and medical interventions can alleviate symptoms such as pain and reduced mobility — and may slow disease advancement.

“Eating more plants and less processed or sugary food reduces inflammation in the body, which can reduce pain from osteoarthritis in all joints,” Cheng said. She also cited strengthening thigh muscles, using knee braces, anti-inflammatory medications, cortisone and other injections, and, in some cases, knee replacement surgery as common treatment approaches.

Prevention begins before symptoms appear

Strategies used to manage knee osteoarthritis — including regular physical activity, maintaining a healthy weight, and consuming whole grains, fruits, and vegetables while limiting processed and refined foods — may also lower the likelihood of developing the condition.

Running, contrary to widespread belief, does not inherently damage knees and remains compatible with joint health when performed appropriately.

“Some people think that because a parent or grandparent had osteoarthritis, they will develop it too,” Cheng said. “And while it’s true that osteoarthritis can run in families, it doesn’t mean there’s nothing a person can do to successfully lower their risk of developing it.”

The condition differs from diseases such as cancer and heart disease but still significantly affects health, well-being, and quality of life for millions. Like those conditions, individual actions may reduce personal and familial risk.