The simplistic formula for losing weight is to intake less and use up more. Less intake means less eating (especially carbs, empty calories, sweets, and excess food), and "use up" means activity and/or overt exercising.
It's not like you have to "exercise" exercise (go to the gym, etc.), to be active enough to burn off the food you eat. If a person were to be always moving all day, never sitting or lying down except to sleep, they would doubtless use up what they have eaten (unless they up their food intake to go with the activity). But most people are limited (by their desk jobs and/or their stamina) in how much "moving all day" they can get in. (Unless you're lucky enough to be a postal carrier who walks his or her route. Basically, those people get paid to keep fit! lol) This is one reason people who want to lose weight add more overt exercise to their routine, such as going to a gym or doing a fitness routine. Among other benefits, it helps them burn calories.
If someone doesn't want to exercise, and can't build other ad-hoc "workouts" into their daily routine (like changing from driving to work to walking to work, for example), but they want to lose weight, they need to reduce their food intake, especially sweets, sodas and junk. They would need to eat the most healrhy foods only, not snack at all, and watch the total amount, eating only moderately sized meals that don't feature a lot of carbs.
You might also reconsider your exercise ban. Your heart will thank you if you get more exercise, as will your brain. "Exercise" is not all "doing exercises" or working out at the gym. Just adding walking to your routine might be a big help.