Water convolvulus (kangkong) is 19 kcal per 100 g. One of the lowest-calorie leafy greens you can eat. A staple in Southeast Asian stir-fries (kangkong belacan, rau muống xào). Even a generous 200 g serving is under 40 kcal. Log for volume, not calories.
How should I track Water convolvulus?
Water convolvulus is a good source of magnesium. For consistent tracking of Water convolvulus, 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.