Red leaf lettuce has 13 kcal per 100 g. Among the lightest salad greens. The red color adds visual variety without any calorie difference worth tracking.
About this food
How should I track Lettuce, red leaf?
For consistent tracking of Lettuce, red leaf, weigh it raw. Cooking method changes both weight and calorie density — steaming barely changes anything, but roasting with oil or frying can double the calories. A systematic review (Whitton et al., Adv Nutr 2022) found vegetables are omitted from food logs 2–85% of the time, often because people assume they are "free" calorically. While most vegetables are indeed low-calorie, the fats added during cooking are not. Log the oil, butter, or dressing separately to keep your tracking accurate.