We become overweight when we consume more calories in food & drinks than we burn each day. To lose weight, a person needs to shift that balance and burn more calories than he/she consumes. You can accomplish that by consuming fewer calories, exercising more, or both.
For women, substantial increases in exercise are not enough to produce weight loss if they did not change their eating habits and eat fewer calories. Men, however, tend to be able to burn more calories in exercise than women and are able to lose weight through increased exercise.
Making your body leaner has many benefits. One pound of muscle can burn 30-50 calories per day, whereas one pound of fat can only burn only 3 calories per day.
So, to get to your goal weight, it is a great idea to get on an exercise plan. Three or more times per week would be great.