You won't lose any weight unless you make a change. You have to exercise to burn fat, and you cut as much refined sugar out of your diet as you can to stop fat from coming back. Add protein (meats, dairy, beans and other high-protein foods) to your diet to replace sugar and fatty foods. Top it all off with some cardio or weights and you are on your way to losing weight.
It just doesn't work that way. You have to take in less calories (diet) than you burn to lose weight. Diet can help you lose but a regular exercise program will give you a better chance of long term success with permanent wt. loss. Take a walk, use the stairs, bicycle, roller skate. Try to find something you ENJOY doing and someone to do it with you and try to do it every day.