Forty calories per 2 tablespoons sounds almost too good for something made from durian, right? The numbers here are honestly a ballpark estimate because hard data on fermented durian is basically nonexistent in any nutrition database worth citing, so take these figures with some salt, literally. What we do know is that fermentation doesn't magically add fat or sugar, so plain tempoyak stays close to durian's natural calorie profile. Carbs are the dominant macro in durian, not fat or protein, which is why the macros here lean carb-heavy at roughly 4g carbs per 2 tbsp. The issue is never the tempoyak itself. It's what surrounds it. You have tempoyak as one of four lauk on your nasi campur plate, you're staring at 600 calories total before you've even sat down properly, bro.
The maths changes completely the moment tempoyak gets cooked into something. Sambal tempoyak at 45 calories per portion is still fine as condiments go. But ikan patin masak tempoyak or masak lemak with santan? Now you're eating a proper bowl of coconut milk curry, and that 30g of tempoyak has absorbed fat from the gravy and brought fifty other ingredients along for the ride. Keep it as a side condiment and the calorie cost is minimal. Order it as the cooking base in a curry and it depends entirely on how much santan went in and how big your portion is.