The ketogenic, or keto, diet is a very low carb, high fat eating plan on which carb intake is often restricted to less than 20-50 grams per day. As such, many high carb foods are considered off-limits on this diet, including certain types of grains, starchy vegetables, legumes, and fruits. However, some fruits are low in carbs and can fit into a well-rounded keto diet. Some are also high in fiber, an indigestible type of carb that doesn't count toward your total daily carb count. That means they contain fewer net, or digestible, carbs. This is calculated by subtracting the grams of fiber from the total grams of carbs.Though avocados are often referred to and used as a vegetable, they're biologically considered a fruit. Thanks to their high content of heart-healthy fats, avocados make a great addition to a ketogenic diet. They're also low in net carbs, with around 8.5 grams of carbs and nearly 7 grams of fiber in a 3.5-ounce (100-gram) serving. Avocados provide an array of other important nutrients as well, including vitamin K, folate, vitamin C, and potassium.