Many people use a ketogenic diet to help them lose weight. While a ketogenic diet is not essential for weight loss, many people still find it helpful.
There are several reasons why a ketogenic diet helps with weight-loss:
First, a ketogenic diet helps many people curb cravings for sugar and for high carb foods (like cakes, soda donuts, and pizza) that can often derail any attempt at a healthy weight-loss diet.
Second, most people on a ketogenic diet find that they are less hungry (partially due to the high fat content of the foods) and so they naturally eat less without even trying.
Third, a Paleo ketogenic diet is more nutritious (i.e., they contain fewer empty calories) so your body is less likely to suffer from vitamin and mineral deficiencies that can often make you feel a need to eat more food.
However, no diet can guarantee weight loss. Some people just naturally do better on a higher carb diet. Other people have more serious health problems that make losing weight tough on any diet. So, I would highly recommend talking to your doctors and running some tests if you find a ketogenic diet is not helping you lose weight.