Diets don't work for various reasons. Often times they are too restrictive and only cause you to slip-up and go back to your old ways. One of the most restrictive diets are those that require you to count calories. I have tried counting calories before and gave up within a week. Life is busy enough without having to account for every calorie that you eat.
I've come across many diets but have ultimately realized that the best way to lose weight without counting calories is by cutting out the foods that keep you fat. These foods are carbs such as bread, rice, baked goods, and other processed food. You don't need to follow a diet but make an important lifestyle change. Two eating plans that I recommend are the paleolithic diet and the clean eating diet. Neither require any calorie counting (unless you want to.)
The paleolithic diet is based upon the eating plan of the hunter-gatherer. This diet consists mainly of meat, vegetables, fruit, and nuts. The clean eating diet is similar excluding all processed foods. Just like any diet, it's easy to start but even easier to slip and eat foods you shouldn't.
If you're used to eating anything you want, you can make the transition easier by slowly incorporating your new way of eating. As you may notice, both diets avoid processed food (which aren't very healthy anyway) so cutting back gradually on junk food and fast food will allow you to become accustomed to eating the proper foods without feeling guilty every time you "cheat."
The best thing about eating clean or following the paleo diet is that you don't have to keep track of calories. Another diet that makes the transition to healthier eating much easier is the "Every Other Day Diet" by Jon Benson. You can eat your favorite foods without worrying about calories.
