Now, about that whole low-fat and low-sugar thing. It can be tricky come dessert time, but Gorin has a hack for surviving that as well: "One way to feel like you’re getting the dessert that you crave while still following the diet is to eat a fruit-based 'nice cream,' like my chocolate-banana recipe. By combining frozen bananas and unsweetened cocoa powder, you'll wind up with a treat that resembles the texture of ice cream yet contains no added sugar and also counts toward your daily fruit servings."
DASH is based on the following foods: fruits, vegetables, low fat milk, whole grains, fish, poultry, beans, and nuts. It recommends reducing sodium, foods and beverages with added sugars, and red meat. The diet is heart-friendly as it limits saturated and trans fat, while increasing the intake of potassium, magnesium, calcium, protein, and fiber, nutrients believed to help control blood pressure. 
On a ketogenic diet, your entire body switches its fuel supply to run mostly on fat, burning fat 24-7. When insulin levels become very low, fat burning can increase dramatically. It becomes easier to access your fat stores to burn them off. This is great if you’re trying to lose weight, but there are also other less obvious benefits, such as less hunger and a steady supply of energy. This may help keep you alert and focused.