If a sandwich has more than one of the same ingredient, it has a nutritional value as though it only contains one of those ingredients. For example, if you made a sandwich with two garlics (and a non-vegetable ingredient such as cheese), it would only give 1.6 to vegetables (80% the value of one garlic), rather than 3.2, (80% value of two garlics).

This is also true for bread: A sandwich made from two pieces of rye bread will only give 0.8 to grains (50% of one rye bread), rather than 1.5 (50% of two rye breads).