How to lose weight with diet plan?

I weigh 100 pounds, 5 foot 1, and am 20 years old. I’m not overweight or underweight but I do have a bit of a belly that sticks out. I want to minimize it but I have arthritis making a lot of exercises difficult. Would eating less bread, pasta, sugar, and red meats help? Would becoming more vegetarian help too? And long walks everyday as well?