 In the early 21st century, non-hydrogenated vegetable oils that have lifespans exceeding that of the frying shortenings became available.As fast-food chains routinely use different fats in different locations, trans fat levels in fast food can have large variations.Some studies have found that deep frying in olive and sunflower oils has been found to be less of a detriment to health and in some cases have positive effects on insulin levels.