Fried food is widely consumed in India and worldwide. Frying is a complex cooking process that modifies the composition of foods and the frying medium through oxidation, polymerisation, and hydrogenation. During frying, foods can lose water and absorb fat, and the frying oils deteriorate, especially when reused. Moreover, frying makes food crunchy and more appetising, which can lead to excess intake. Several studies done on US population showed that higher consumption of fried foods was associated with an increased risk of Type 2 diabetes and cardiovascular diseases, which are among the leading causes of death. However, little is known about the relation between fried food consumption and mortality.
A study carried out by US researchers which is published in the BMJ journal entitled “Association of fried food consumption with all cause, cardiovascular, and cancer mortality: prospective cohort study,” concluded that frequent consumption of fried foods, especially fried chicken and fried fish/shellfish, was associated with a higher risk of all cause and cardiovascular mortality in US women. Earlier studies found fried food consumption was associated with a higher risk of heart failure, acute myocardial infarction (heart attack) total ischemic heart disease, and death.
Frying practice and medium vary by cooking tradition and the location where fried foods are consumed. How does frying deteriorate food quality? The food could lose water and absorb fats during frying, which would increase the energy density of food. Frying could also lead to excess energy intake by making food more aromatic and appealing in texture, thus improving food palatability. Additionally, frying deteriorates oils through the process of oxidation and hydrogenation, leading to a loss of unsaturated fatty acids such as linoleic acid and an increase in the corresponding trans-fatty acids such as trans-linoleic acid.
Another possibility is the higher levels of dietary advanced glycation end products as a result of frying, which could have an important role in the development of cardiovascular disease, mainly through induction of oxidative stress and inflammation. Moreover, frying at a high temperature can lead to acrylamide formation in some foods, such as French fries and potato chips, which is associated with higher risk of cardiovascular and cancer mortality. In addition, reused cooking fat could inhibit the activity of paraoxonase, an enzyme that inhibits the activity of low density lipoprotein cholesterol, which is involved in the pathogenesis of atherosclerosis.
High sodium present in ultra-processed foods like chicken or fish could partially contribute to the higher mortality risk. As sodium accumulates, the body holds onto water to dilute it, which increases both the amount of fluid surrounding cells and the volume of blood in the bloodstream. Increased blood volume means more work for the heart and more pressure on blood vessels, which over time, can stiffen blood vessels, leading to high blood pressure, heart attack, and stroke.
