Are there any exercises that don't strain the joints?

hello. .

I used to be able to control my weight quickly just by eating a little less, but lately, I’m upset because the fat around my belly and arms just won’t go away, perhaps due to age. I don’t have the energy to just starve myself, and while I want to start exercising for my health, my knee joints aren’t what they used to be, so I’m even cautious about walking.

Are there any middle-aged women like me who have found an exercise effective for losing body fat without straining the joints?