Sugar free. Low calorie. 80% Less calories than regular blackberry preserves. (Fifty 50 Blackberry spread contains 10 calories per serving compared with regular blackberry preserves which have 50 calories.) For use in a low glycemic diet. Nutra Sweet. Exchange information for people with diabetes: One tablespoon equals a free food exchange. Calculations based on Exchange lists for Meal Planning, 2003 American Diabetes Association, Inc., The American Dietetic Association.