"Diets" don't work. Ever. They lower your caloric intake to a point that you'll lose weight, but diets arent maintainable long term. You lose weight, but then what? You can't sustain a 1k calorie intake the rest of your life. It isn't realistic, and it's not healthy.
Better idea is a realistic, long term change in your lifestyle. Something that will help to lose weight but is also maintainable long term. Cut out certain things- soda, fast food, rich coffee drinks, etc. Eat real food- lean meats, veggies, healthier options for carbs- sweet potato, brown rice, black beans.
The Paleo diet certainly has a point. Eat the way cavemen ate. Only foods in their natural state. Meats. Veggies, fruits, (dairy certainly existed, and still exists- but today it's extremely processed.) But the human today isn't the human of the caveman days either.
The best thing you can do for yourself as far as nutrition is to eat whole foods. Foods unprocessed. Lean meats- chicken, turkey. (Sometimes lean beef). Lots of Veggies. Limit the fruit. Eat sweet potatoes, brown rice, sprout breads, black beans etc. It's tough but worth it. And exercise helps a lot!
I personally eat in a way that benefits me gaining/maintaining muscle, and I also weight lift 5 days a week. I eat a shit ton of chicken, some turkey, occasionally a Filet, a lot of vegetables. No fruit. No dairy. A lot of sweet potatoes. Fish oil every day, a probiotic, and calcium