What are the differences between low carb, low fat, and low glycemic diets?

The difference between the carbs and glycemic index is the type of carbs. You should stay away from simple and starchy carbs, which has a high glycemic index, this includes any sugars (even some fruits) and starchy carbs such as potateos, white rice and most breads (mainly enriched). You should be eating low glycemic foods which take longer to digest, these would include green leafy veggies, whole grains, and other veggies such as roots and beans. Low fat should not mean no fat, you just have to consume the correct fats. Stay away from saturated fats such as butter, margerine, and vegetable oils. Go for Olive oils and leaner nuts such as pecans and walnuts.