Honestly, 100 calories for a full plate of vegetables is pretty hard to beat. This is blanched sawi, so the veg itself only contributes about 42 kcal. The oyster sauce adds another 13 kcal, and the garlic oil drizzle is where the biggest chunk comes from, around 40 kcal from just 9g of oil. Total is ballpark 100 kcal, but I want to be upfront: solid nutrition data for this dish specifically is thin on the ground, so treat this as a reasonable estimate rather than a lab reading. That said, even if you're off by 20 to 30 calories either way, this is still one of the lightest sides on the menu. If you're the kind of person who used to skip vegetables to save room for more rice (yes, I was that person at 128kg), this is worth rethinking. Broccoli sos tiram ordered at the same stall will be very similar in calories, though broccoli is slightly denser so a 180g plate may land a little higher, closer to 110 kcal.
What actually changes the maths is almost always the oil. A stall that goes light on the garlic oil can drop the whole plate to around 50 calories. A stall that wok-fries instead of blanches, or is generous with the drizzle, can push it to 140 kcal or more. The sauce itself is not the villain here, 25g of oyster sauce is only 13 kcal. So if you want to order this guilt-free every single day, ask for less oil lah. Portion-wise, 180g is a standard plate. If you pile on a bigger serving, scale accordingly but even 300g of this side is still under 170 calories, which is basically nothing compared to what it does for keeping you full alongside your rice.