@Jockette I eat meats, vegetables, fruit, homemade 100% whole wheat bread sometimes, cauliflower rice, zucchini for pasta and in things like enchiladas instead of tortillas, or in lasagna in place of lasagna noodles, and so on. We do eat tacos sometimes as the taco shells I buy aren't too bad calorie or carb-wise, and I only eat one or two of them. I usually make them with my homemade smoked pulled pork, some Monterey Jack cheese, tomatoes and shredded cabbage (I always use shredded cabbage for tacos instead of lettuce-it's crunchier and doesn't get soggy). When I do eat something like the potato salad I made for company last week, I eat a very small portion, and it's only on rare occasions.
If I make burgers, we either eat lettuce wrapped burgers, or I make beer can burgers. There isn't any beer involved-the recipe calls for you to use a beer can to shape the burger, although I use a straight sided glass for shaping since I don't have any cans of beer around here. I fill them with peppers, mushrooms, onions, some cheese and bacon. The original recipe calls for buns, but they're better (IMHO) with no bun as a main dish. I also make one burger and split it between my husband and I as it's a large burger, too big for one person.
Basically, I don't eat sweets or desserts any more, nor white bread; no potatoes, no pasta, etc. I also keep my calories to 1400 per day max. Basically, losing weight, no matter your activity level, comes down to taking in less calories than you burn off each day. I watch all the components such as carbs, fat, etc also, but make sure to keep my calories low.
Losing weight when you can be active, riding bikes, swimming, long walks, etc, is a lot easier, but when you've had a recent TKR, or need one, moving around a lot isn't always possible. Most people recover after the surgery and can be active again, but I'm still limited so have to be more careful with what I eat since I can't help it along by being more active. Being active doesn't burn a ton of calories, unless you're a pro athlete maybe, but a couple hundred calories burned per day being active adds up over time, plus the activity keeps your metabolism revving for a while after.