Paleo Diet is another popular diet. You have a list of foods to eat and a list to avoid. Sound easy enough, eat all the Paleo friendly foods and you wont gain any weight. Lookup Paleo treats or Keto treats. With all the options out there it makes it seem that being paleo or keto friendly treat means you can eat as much as you want and not gain any weight. I consider very low carb Paleo or low carb Paleo to be similar to Keto if you stick to clean eating with exception of added fats that Keto promotes. This is where Primal differentiates it self from Paleo by allowing added fats like real butter or coconut oil.
Whole30 diet I find pretty similar to Paleo as well, it has a list of foods you are allowed to eat and a list of foods to avoid.
You need to look at all of these diets, Paleo, Keto, Whole30, Mediterranean diet and try to figure out where they overlap and what do they have in common. In their pure basic states they all promote clean eating. Animal meat for protein and plenty of vegetables are on this list of all these diets, and depending if you are watching carbs or you eat fruit. So to keep things simple just eat meat, vegetables, and fruit, minimizing processed foods (anything that comes out of the box or freezer) we can setup a simple meal plan that can set us on a clean eating journey.
So why do people fail on the diets above or other diets. We all believe if we stick to the foods of the diet then how much we eat does not matter. This is simply not true. Many people can overeat on any food, even if its an approved food. And if you overeat, means eating more food than your body needs for energy for the day, and if you do this everyday, then you will gain weight.
Clean eating is the base foundation of Keto, Paleo, Whole30, Mediterranean diets we mentioned and is a base foundation of many others. But controlling calorie intake just by simply avoiding certain foods or eating foods of an approved list may not be enough for everyone. If its not working for you than its time to look at total calories you consume in a day compared to total calories you burn.