Olive oil isn't really "healthy". It's health
ier than vegetable oil at - and here's the important bit - room temperature, but once it's been heated beyond its smoke point the monounsaturated fats break down and it becomes just as horrid for you as any other oil. Cooling it down again doesn't re-create the lost atomic bonds.
Either way it still has exactly the same calories as vegetable oil, peanut oil, or whichever other oil you choose to use.
Frying in soy sauce... No. I wouldn't do it. Soy sauce concentrates as it evaporates, so if you allow it to boil what you'll end up with is a sticky, salty mess (I seem to be full of innuendo today! Sorry!) which will cause you grief when it comes to washing your wok - especially if you're using a non-stick pan. Kiss goodbye to the teflon if you have to scrape encrusted soy sauce off it too often.
I have a few suggestions here:
- Use the oil of your choice. For stir-frying I reccommend peanut (groundnut) oil because it has the highest smoke temperature and the best flavour for stir frying. But once you've added a small dollop, wad up a sheet of kitchen towel and use it to smear the oil around the wok. Any excess oil will be absorbed into the kitchen towel, which you can then bin.
- Use a few spritzes of Fry Light, but do be aware that this stuff can't take as high a temperature as oil, so you'll need to keep a close eye on your wok to prevent sticking.
- Include your oil when calculating the calorie cost of your meal, and just accept it when figuring out the calories available to you for the rest of the day.
- Fry in fish sauce. It's about as salty as light soy (so, saltier than dark soy), but doesn't devolve into a sticky mess (there I go again) when you get it to a useful temperature. It does add a faintly fishlike flavour to your cooking, but many thai dishes actually require that

- Practice your wok-fu. The art of using a wok successfully is to use one without any non-stick coating, and allow it to get as hot as possible before throwing your ingredients in. You cook fast, then evict the food from the wok, all within about 2-5 minutes. And if food's in there for that little time, you'd be surprised how little oil you can get away with using. If you've got your stir-fry cooking away in a wok for 20 minutes that's at least 15 minutes too long.
By all means throw the soy in a few seconds before you serve. But don't fry in it.
Of course, I'm an Asian cooking purist, so you don't have to listen to me
