High-fat fish: The mainstay of a keto diet is eating foods that are high in protein and low in carbohydrates. Animal protein, vegetables, dairy products, plant-based protein, lipids, and oils are all permitted on this diet, as are a range of fruits and vegetables. Your diet should mostly consist of entire, single-ingredient meals. Eat fatty fish like salmon, trout, tuna, and mackerel as part of your diet.