Judo Josh is right. You could be eating a Paleo diet and still be putting on weight. However, if you do it right, the Paleo diet when followed properly (how people advocate) is not only about the quality of the foods you are eating, but it's about nutrient timing as well.
It's mainly about eating whole foods, cutting out any foods that may cause possible allergic reactions (which cause water retention, inflammation, etc). But for example, you can eat sweet potatoes on it amongst other high carb / calories dense foods. For this reason, advocates of the Paleo diet recommend eating starchy foods around your workouts.
I'd say overall that people who follow a Paleo diet will definitely see body composition changes. But if you have strict goals, look for a diet that's geared towards fat loss, for optimal effect. For example, you could possibly follow a cyclical ketogenic diet, but if you choose to - you could strictly eat only Paleo type foods within this diet plan. This would be a much healthier way to eat than how many people will eat on a CKD, as it cuts out dairy / grains / inflammatory foods. This is just one example though.
