Our exchange feature follow the principles for exchange nutrition planning, with 1 point or serving equal to 15g Carbohydrates, 7g Protein, and 5g Fat. If you’re not able to add a certain food to a specific category, then the food is outside of the standards for that category. The range is set at 20% for macronutrients, so for a food to be classified in any particular category (Carbohydrates, Protein or Fat) it needs to contain at least 20% of its calories from that nutrient (20% calories of carbohydrates, for instance). If below this, the content is not high enough to fall into that particular category. In this scenario users with our Professional edition are able to add foods to the database, which will allow you to create custom foods you want to include in the exchange plans.