Durian is not a light snack. It is a calorie-dense fruit that sits somewhere between a dessert and a meal. The richness you taste in a good Musang King or Black Thorn seed? That is fat, specifically oleic and linoleic acids, the same types you find in nuts and avocado. Not bad fat, but still fat, and fat has 9 kcal per gram. Add the natural sugars and you get a fruit that hits 147 kcal per 100g for standard D24 and up to 175 to 180 kcal per 100g for the premium grades. Most fruit sits at 50 to 80 kcal per 100g. Durian is basically in a different weight class.
The maths changes fast based on variety and portion. Four seeds of kampung durian is about 145 calories, manageable. Four seeds of Musang King is 210 calories. A full kampung durian at the pasar malam is 600 calories. That is nearly a full meal worth of calories from fruit alone, eaten while standing, usually followed by more food. If you are tracking, weigh the flesh or count seeds honestly. Going from 4 seeds to 8 seeds does not just feel like double the enjoyment, it is double the calories.