Not all oils are stable enough or intended for use in cooking, particularly in high heat preparations. Others do better in cold preparations or used as dietary supplements, for example.

The following oils are best to avoid when it comes to high heat cooking:

1. Fish or algae oil. These are intended to be omega-3-rich dietary supplements that you should take cold and in small doses. Don’t use these products for cooking purposes.

2. Flax oil. While high in the heart-healthy unsaturated fatty acid alpha-linolenic acid (ALA), this oil has a low smoke point at around 225°F (107°C), and you should reserve it for cold uses like salad dressings.

3. Palm oil. Health-wise, palm oil is calorie-dense. The main problem here is ethical, as the production of palm oil has been strongly linked to rainforest destruction and a loss of biodiversity.

4. Walnut oil. This oil is high in ALA and offers some anti-inflammatory and potential anticancer benefits. However, it is also best to reserve for cold preparations like salad dressing. It has a lower smoke point, sitting around 320°F (160°C)