Just only buy high-grade oil?

Compared to three-grade oil and four-grade oil, high-grade oil and secondary oil have indeed a lot of advantages. High smoke point, fewer impurities, low harmful ingredients when cooking smoke fumes is relatively small. However, because of the high degree of refining, there have to be more nutrient loss, fragrance are often not as rich as level 3 and level 4 oil.

In other words, they both have weaknesses and strengths. we buy just according to our own preferences to choose on the line. We can also use the level 1 and level 2 oil cooking, level 3 and level 4 oil to do that do not require high temperature stir vegetables. Do not worry about the low level oil is hazardous to health, provided that they meet national quality standards and health standards, even if it is level 4 oil, also can safely eat.