Cucumber with peel has 16 kcal per 100 g. The peel adds fiber and crunch. At 16 kcal, cucumber is effectively a free food in any calorie budget.
About this food
How should I track Cucumber, with peel?
For consistent tracking of Cucumber, with peel, 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.