how many carbs in lettuce?
1 1.7 grams of carbohydrate in 1 cup of shredded/chopped iceberg lettuce. 2  3 grams of carbohydrate in 3.5 ounces, or 100g, of iceberg lettuce. 3  16-17 carbohydrates in 1 medium head of iceberg (6 inches diameter). 4  1 gram of carbohydrate in 1 ounce, or 28g, of soft green leaf lettuce types.