Diet comes from Latin, and it describes a way of living. The perfect diet would need to be a life long plan for better health, including exercise and eating healthy, always, not just to lose a few pounds.
The only real weight loss diet that exists, is to consume fewer calories then your body demands in a single day. The ones that let you eat “however much you want of this, but none of that” don’t work, because they don’t address how weight loss occurs. You need to create a 3500 calorie deficit to lose a pound. That’s the only way. So to lose weight I’d say eat between 1200 and 1500 calories per day until you reach your target weight. The healthier the foods are that you choose the easier it will be to stay on the diet and meet your goals because they are more filling and actually provide the necessary nutrients for your body. If you’re going to do this, I also recommend getting on a daily vitamin, because you will likely not be consuming enough nutrients in a day.
Exercise is your friend cause it burns more calories, thus increasing the amount the body needs, and making your deficit number higher (or okay allowing wiggle room cause that is important too :P).
Good luck!