Exercise and diet. I would try daily exercise consisting of cardio and some resistance training as well as earing healthy foods paying attention to portion sizes. Eat low glycemic, high fiber foods such as fruits, veggies and whole grains. Consider talking to a dietitian.
Weight Loss. The balance is diet and exercise. Portion sizes are important to manage. The mediterran diet has good data on weight loss. Exercise with periods of increased activity (interval training). Just keep trying.