When people with severe obesity lose a lot of weight, they start walking differently — taking longer steps and moving faster — and this might actually reduce some of the benefits that weight loss should have on their knees when walking every day.

If someone with severe obesity loses about a third of their body weight, their knees experience nearly two times less pressure when walking — meaning their joints get a lot more relief than the weight they lost would suggest.

After people with severe obesity lose a lot of weight, they tend to walk faster and take longer steps, which means their knees don’t get as much relief as expected — the pressure only goes down by about a third instead of two-thirds, so the knee load drops about as much as the weight they lost.

If older adults with extra weight and knee arthritis lose 1 kilogram, their knees experience about 4 times less force with each step — which could really add up to less wear and tear over time.