Since blue agave nectar appears to be in the fruit category, you would consume it as you would a portion of fruit. Usually on an empty stomach and three hours before or after eating either carbs with veges or protein/fats with veges.

The sugar free ones usually have "dairy solids" of some sort which would mean they are partially dairy. If there is fat with the sugar free then the answer is no. If you see a fat free and sugar free and don't mind the chemicals, you will need to check the ingredients to see if it is a fat/protein or a non fat dairy category. Make sure you are combining it with the right food group with whatever you are eating it with. You could use the sugar free vanilla "syrup" and then fat free milk to make your own and then eat with a dairy / whole wheat breakfast.

The Susanne Somers Diet, also called Somersizing, is essentially a low carbohydrate plan that emphasizes food combinations. It's a two-phase plan, with the first phase devoted to weight loss and avoidance of what Somers calls "funky foods." These include sugar, white flour, honey, maple syrup, carrot, avocado, banana, sweet potatoes, nuts, whole milk and yogurt. Combination rules include eating fruit alone and on an empty stomach, combining vegetables with fats and proteins, combining carbohydrates with vegetables and waiting a minimum of three hours between meals with different combinations.