Hellman's Mayonnaise (Best Foods, for shoppers in the western US) is the favorite brand of Cooks Illustrated and Cooks Country test kitchens, but for all its good qualities, mayonnaise can add a tremendous amount of fat to a sandwich or a dip. Cooks Country compared four varieties of their favorite mayonnaise brand this month to see if you could cut back on calories by switching to a lower fat version, or whether you're really missing out if you do.
The types taste tested were Hellmann's regular, canola oil, light and reduced fat. Unfortunately, the tasters all really preferred the original, full-fat (9g per each 1-tablespoon serving) variety and said that it provided the best flavor when tasted alone and in a dip. The reduced fat (only 2 grams fat per 1-tbsp serving) didn't have nearly as much flavor, but it still produced a creamy texture in dips.
Since most people don't want their spinach dip to taste like straight mayo anyway, you can save some fat and calories by using one of the lighter mayos in your dips and save the full-fat for when flavor really counts, on a sandwich.