Sweet and sour pork is a three layer problem. The pork is shoulder or belly with visible fat. It is coated in batter and deep fried, which soaks up oil. Then it is tossed in a sauce that is mostly sugar, vinegar and ketchup. CFS found that a single portion sample carried 35g of sugar, which is 70 percent of the WHO daily limit of 50g, before you count the rice under it. That sauce is why it topped the sugar column in the survey.
The per 100g numbers tell you how fast it adds up. At 240 calories per 100g, a normal 200g rice plate portion is 480 calories from the pork alone, and dai pai dong portions of 350g served on a shared plate are 840 before anyone has touched the rice. Compare that to steamed chicken with mushroom at around 90 calories per 100g. Same amount of food on the plate, less than half the energy.
The rice plate version is at least portion controlled. A full cha chaan teng plate at about 800 calories is lower than a plate of baked pork chop rice (1,300) and in the same range as a roast pork rice (930). What tips it over is the second helping of sauce most shops ladle across the rice, which is another 60 to 80 calories of pure sugar, and the fact that fried batter holds oil long after it leaves the wok.