A ketogenic diet follows a strict ratio for total grams of fat to combined grams of carbohydrate and protein and typically has 80-90% of total kilojoules coming from fat, which is very high fat.
Research on the use of classical ketogenic diets for weight loss is limited. But there are many studies that compare lower-carb diets to other approaches.
You will find that in most cases Keto diets will help in weight loss by creating a kilojoule/ calorie deficit. But may not be the healthiest or be adhered to long-term.
For more info on keto diets check here: https://theconversation.com/do-ketogenic-diets-help-you-lose-weight-81810.
And for tips on how to lose weight without FAD diets check this out: https://theconversation.com/health-check-six-tips-for-losing-weight-without-fad-diets-52496.