Dietary fat intake is mandatory. It's an essential macronutrient, meaning you would literally die if you ate no fat.
Other than life, it's also good for proper hormone production, absorption of certain vitamins, protects your organs, helps control inflammation, improves nutrient partitioning (that means it will help you lose fat), and it keeps your coat shiny. ;)
How much you need is debatable, but until you develop proper habits (meats, veggies, nuts at every meal) I wouldn't worry about exact grams or percentages.