The healthiest way to cook vegetables is to fry them, according to a study by researchers from the University of Granada — as long as you use extra virgin olive oil.
The research, published in Food Chemistry magazine, finds frying improves antioxidant capacity and increases the amount of phenolic compounds, which help to prevent conditions such as diabetes and cancer.
The researchers carried out an experiment to determine the healthiest method of cooking Mediterranean vegetables. They cooked 120 grams of potato, pumpkin, tomato and aubergine by either frying them in extra virgin olive oil or boiling them in water. They found that frying increased the vegetables’ fat content and reduced their moisture.
The study’s co-author Professor Cristina Samaniego Sánchez said: ‘Comparing the content of phenols with that of raw vegetables we found increases and reductions alike, depending on the chosen method. Oil as a means of heat transfer increases the amount of phenolic compounds in vegetables, [as opposed] to other cooking methods such as boiling, where heat transfer is done through the water.
‘Therefore, we can confirm that frying is the method that produces the greatest associated increases in the phenolic fraction, which means an improvement in the cooking process, although it increases the energy density by means of the absorbed oil’ — and so the fried vegetables will also be more calorific.