What grumpyphil said is right. You need to eat a balanced diet for the long term. Lowering your fat intake is good for general health as well as losing weight. If you want to put on muscle then lift weights and increase your protein intake a bit. Don't try lifting more than 3 times a week, but cardio you can do as often as you like.
Calories are everything. Find your Base metabolic rate and aim for 500 calories beneath that and adjust over time. Then any exercise you do will bring your weight loss to 1-2 pounds a week.
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