Each single pound you weigh adds 4 lbs. of pressure to your knee joints when walking, and more when running or climbing stairs.
Thus (obviously) if you are 20 lbs. overweight, your knees experience it as equivalent to an 80 lb. backpack - plus the normal effect of the rest of your ideal weight. Knees were not designed for 80-lb. backpacks 24 hrs./day. Over years, the damage increases of course until, one sad day, you finally begin to feel the accumulated damage.
...individuals who lost 10 lbs. would be subject to a total of 48,000 less pounds of pressure for every mile walked.
Walking when overweight is brutal to knees and, from the knee point of view, probably is to be minimized until losing weight. Driving is kinder. Being carried by slaves in a litter is even better because it is kinder to Gaia.
Besides trauma (eg accidents, athletic injuries, athletic overuse and related overuse as in dance), extra weight is the main cause or exacerbation of knee arthritis. It's all about gravity and the pounding your knees take with every step.
Unless the idea of knee replacement appeals to you, the kindest thing you can do for your knees (or your hips, for that matter), is to lose weight - or to be carried around town. Or, like you see in WalMart, maybe Medicare will buy you a $25,000 electric wheelchair.
Americans eat too much, and far too many carbs than is good for them. (Soon, I'll repost the Dr. Bliss diet which I follow diligently to stay under 130 - plus lots of athletics. It is essentially carb-free, except at Birthday Parties and special occasions. Absolutely no fruit allowed - fruit is sugar and a sugary dessert, and there is nothing "healthy" about it.) Here are some links about weight and arthritis.
Happy Knee photo via Theo
Image below is Cleopatra, keeping her knees youthful and healthy.
