Body Weight and Knee Pain

Medically Reviewed by Tyler Wheeler, MD on September 19, 2022
4 min read

Your knees are powerhouses. They’re the biggest, strongest, joints in your body, and most people use them throughout the day to sit, stand, walk, jump, and bend. They bear 80% of your body weight when you stand still and 150% or more when you walk across the room. In a 160-pound person, that’s 240 pounds of force!

More weight puts more strain on joints and on the cartilage that protects the ends of your bones. Extra body fat also sometimes increases chemicals in your blood that inflame your joints.

Both these things can lead to osteoarthritis (OA). In this condition the smooth, slippery cartilage that covers the ends of bones in a joint slowly wears away. Instead of gliding over one another, your bones rub against one another.

Symptoms like pain, swelling, stiffness, and loss of motion often get worse over time.

Normal wear and tear is another leading cause of osteoarthritis, especially after age 50. Extra body weight can also cause OA or make it worse if you already have it.

In addition, extra body fat, especially around your belly, can lead tpo diabetes.The fat triggers your body to stop responding to the hormone insulin, a condition known as insulin resistance.

Weight loss can really help your knees. Drop 10 pounds, and you’ll take as much as 40 pounds of force off them, depending on what you’re doing.

Losing even a small amount can help. And the earlier you do it, the better. Keep the weight off, and you won’t be as likely to get arthritis later in life.

It isn’t just the weight. Fewer fat cells might mean fewer hormones to inflame your knees and other joints. It’s especially helpful if you lose weight with good diet and exercise habits.

Talk to your doctor about your ideal body mass index, a measure of body fat based on height and weight.

Changing your diet will help you lose weight, but eating better food can have other benefits, too.

Healthy eating lessens the inflammation that sometimes causes joint pain. In particular, fatty fish like salmon, tuna, mackerel, and herring are rich in omega-3 fatty acids and are good for this, along with nuts, tomatoes, olive oil, and green leafy vegetables.

It isn’t always easy to put this into a daily diet that works for both weight and general good health. Your doctor or dietitian can work with you to build a plan with the right mix of exercise and diet changes. Or you could try the National Institute of Health’s Body Weight Planner tool, which gives you a meal plan based on your activity level and weight loss goals.

In general, aim for a healthy, balanced diet that you can stick with even after you lose weight. Nuts, beans, eggs, skinless chicken, lean meat trimmed of visible fat, and fish are good proteins. Cover at least half your plate with fresh vegetables, fruits, and whole grains like oatmeal, brown rice, or whole-grain bread.

Exercise that leads to weight loss will help take pressure off your knees. But it, too, has other benefits.

It might lessen chronic inflammation and can strengthen and stretch the complex collection of muscles, ligaments, and tendons that move the knee joint.

Movement keeps your cartilage healthy, too. In fact, people unable to move because of surgery, injury, or illness actually start to lose cartilage in their knees from lack of use.

It’s a good idea to try to mix up your exercise types:

  • Aerobic exercise, like walking, swimming, or rowing, could lessen inflammation and increase your stamina. That allows you to remain active for longer periods.
  • Resistance exercise, like weightlifting or lunges, strengthens and stabilizes muscles around the knee joint, like your hamstrings, calf muscles, and quadriceps.
  • Stretching muscles and connective tissue around your knee helps increase your range of motion, or the distance you can move a joint.

Just make sure you start slow, warm up, and learn the correct technique for any exercise that you do. Talk to your doctor if you already have knee pain so you don’t choose an activity that makes it worse. It may be better to avoid exercise that involves kneeling, bending deeply, or running downhill, which could be especially hard on your knees.