Many people are used to stir-frying only when the oil in the wok is smoking, which is not a scientific practice. High-temperature oil not only destroys the nutritional components of food but also produces some peroxides and carcinogenic substances. It is recommended to heat the wok first, then add oil, and you can start stir-frying without waiting for the oil to smoke.
It's not advisable to exclusively eat vegetable oil and avoid animal oil. In moderate amounts, animal oil (saturated fatty acids) is beneficial to the human body.
Nowadays, it's difficult for the average family to use different oils for different dishes, but it's best to alternate and combine several types of oils for consumption, which is more nutritious.
For the elderly, people with abnormal blood lipids, obese individuals, those with obesity-related diseases, or people with a family history of obesity, the daily oil intake per person should be kept at 20 grams. People with normal blood lipids and body weight should keep their oil intake around 25 grams.