There are three main macronutrients: protein, carbs, and fat. While protein and carbohydrates get much of the attention, it is important to understand how much fat you need as well. Low-fat approaches can be very useful for dieting, but at some point how low is too low to go for your fat intake? That is what we will cover in this NutriWiki article.
Ideally, you’re getting 0.25g/pound minimum. However, when dieting properly, a diet isn’t forever. Typically, your minimum fat intake is set at 15-25% of total calories during a diet, which often works out to be around 0.2-0.25 grams per pound. Once the diet is over or you’re taking a 1-2 week diet break (once every ~8 weeks) fats should be increased to at least 0.3g/pound if they were below that.
As long as you’re getting enough essential fatty acids in your diet you probably don’t need to worry too much about the total fat intake. Essentially fatty acids are fatty acids your body doesn’t make in enough quantity to survive without getting from your diet. Examples of these essential fatty acids are DHA and EPA, which are commonly found in fish oil and other seafood.
According to the International Society of Sports Nutrition, 0.22g DHA & 0.22g EPA per 2000kcal . While those are the minimums, a good recommendation is to be at 1.8g of DHA & 1.2g of EPA / day (most likely via fish/seafood consumption or through fish oil supplementation). You can also get essential fatty acids from plants; however, they contain much lower amounts and the body must convert the fatty acids from plants into the essential fatty acids, and that is very inefficient 
There is no actual established dietary minimum fat intake. While there is a potential for harm, no one knows where that threshold lies.