Larb is one of the few Thai dishes that gets cooked with no oil. The pork is dry fried in a pan with a splash of water or stock, then dressed with lime, fish sauce and roasted rice powder. A plate uses about 90g of mince, and that is 150 of the 200 calories. The herbs, shallots and lime add almost nothing. The toasted rice powder is 5g and about 18 calories.
The number moves with the pork. Standard stall mince is around 20 percent fat, which gives the 200 calorie plate. Lean mince drops it to about 160. Some Isan stalls add sliced pork skin or a spoon of chopped liver, which adds 30 to 50 calories and, in the case of liver, a decent amount of iron. Larb moo tod, the deep fried version shaped into balls, is a completely different dish at about 400 a plate.
The practical point: this is a 200 calorie plate that gives you as much protein as a chicken breast. With a 150g bag of khao niao it is a 450 calorie meal, and with som tam on the side it is 600 and very filling. Most Thai lunch plates cannot do that. Larb gai (chicken) is about 170, and larb pla (fish) around 160.