stew with fries, croquettes cheese or shrimp, fried croustillons are some essential of our culinary heritage. All the little food that cook quickly can be passed to the frying oil, including pieces of meat, fish or vegetables.

Unfortunately, this method of preparation is not healthy. A large study of 70,842 women of Nurses’ Health Study and 40,789 men of Health Professional Follow-up Study shows that there is a link between the consumption of products fried and type 2 diabetes (1). This link is even more evident when the fried products are consumed outside compared to those prepared at home.

This cooking method is also accompanied by a higher risk of cardiovascular disease, although research is less clear on the subject (2). Anyone who eats fried foods more than four times a week will most often confronted with overweight, high blood pressure and high cholesterol. All factors that increase the risk of so-called civilization diseases.

Shock temperatures

Frying causes a series of chemical reactions that make fats decompose, freeing up of harmful degradation products. The extent of this process highly depends on the way they fried, the fat used as well as the food which is fried. The higher the temperature of the fat, the greater the degradation products formed are many. High temperatures also have an adverse impact on antioxidants may hamper the formation of breakdown products (3).

Similarly, prolonged and repeated heating of the fat has a negative effect. There is a direct relationship between the number of fat and uses the formation of harmful degradation products. This is because the presence of oxygen accelerates the degradation process. Gold by immersing large quantities of food in the fryer, more oxygen is introduced into the oil. This is further amplified by the impact of temperatures, for example when frying frozen food or surrounded by ice.

The type of fat

The type of fat used also plays a role in the degradation process. The stability of the fatty acids in the fat is crucial. Unsaturated fatty acids are more susceptible to oxidation and therefore less stable than saturated fats. The more unsaturated fatty acids, less fat is stable and degradation products (cyclic compounds) are numerous. This is why it is recommended not to heat the oil above 180 ° C, and change regularly.

Should we therefore focus on saturated fat? Especially not because they increase for themselves the risk of cardiovascular disease and should therefore be consumed in reasonable proportions. It is best to use monounsaturated oils such as sunflower oil, peanut or corn, especially when the oil is rich or enriched in antioxidants.

They also play a role. They may be naturally occurring (vitamin E oil) or added. Antioxidants inhibit the oxidation of fatty acids, and therefore also the formation of degradation products.

The type of food

Finally, the food that is fried plays a role too, as during cooking is an interaction between the fat and the food. A food rich in liquid, unsaturated fats and starches promotes the formation of degradation products, while the protein would slow. food residues also stimulate the formation of degradation products.

The food is also subject to all kinds of chemical reactions in which form harmful substances such as acrylamide and PAHs (polycyclic aromatic hydrocarbons). More food is fried longer, the harmful substances formed are many.

By Nina Van Den Broecke

Frire in the state of the art

It is not recommended to eat fried products too often. To limit the damage, it must follow certain rules:

– The oil should not exceed 175 ° C

– Do not heat longer than necessary

– Replace completely after 5-10 uses

– Replace immediately the fat that smells strongly, thickens and becomes dark

– Limit the amount of food you dive in fryer basket

– Make sure the food is dry before immersing in fat

– Eliminate charred remains after frying

– do not fried or breaded dishes eat more than once a week.