Short answers, pulled from the story.
Frying first emerged in the Ancient Egyptian kitchen during the Old Kingdom around 2500 BC. This early technique transformed how humanity approached food preservation and flavor by utilizing the unique properties of fats. Archaeological evidence suggests that early cooks utilized open-air methods to achieve a level of control over heat that was previously impossible.
Unlike water, fats can reach temperatures much higher than 100 degrees Celsius before boiling. This thermal property allows for the rapid searing and carbonization of food surfaces while maintaining a sterile and dry end product. The ability to cook food much more quickly than other methods has made frying a global phenomenon.
Deep-frying involves totally immersing the food in hot oil, which is normally topped up and used several times before being disposed of. Shallow frying uses only enough fat to immerse approximately one-third to one-half of each piece of food. The fat used in shallow frying is typically only used once, whereas deep-frying oil is often reused.
A 2021 meta-analysis found that the highest category of fried food consumption compared to the lowest is associated with a 3% increase in the risk of all-cause mortality. Those who ate the most fried food had a 37% increased risk of heart failure, a 28% increased risk of major cardiovascular events, and a 22% increased risk of coronary heart disease. The study concluded that fried food consumption may increase the risk of cardiovascular disease and presents a linear dose-response relation.
A 2023 meta-analysis found that fried food consumption is linked to a 52% increase in the risk of stomach cancer. Fried food intake is also associated with prehypertension, hypertension, and obesity, creating a complex web of health risks that extend beyond cardiovascular issues. The high temperatures used in frying can generate harmful compounds that contribute to the development of chronic diseases over time.