How Safe Is It To Reuse Cooking Oil? Experts Weigh In

Can you imagine a kitchen without oil? Most recipes use oil as the basis; in fact, it is the first ingredient that kickstarts the entire cooking process. Whether we're sauteing vegetables or frying pakodas, oil plays a crucial role in cooking and enhancing the taste and texture of our dishes. While oil is absorbed in the foods while cooking, the frying method leaves us with unused oil. In many Indian households, it is a common practice to save leftover oil from frying pakoda, samosas or pooris for later use. This recycled oil is often used for deep-frying again, but some people also use it for tempering, sauteing ingredients for other recipes or preparing paranthas. However, the safety and health implications of reusing cooking oil have raised concerns. Is it safe to reuse the oil left from the previous frying session? Let's find out.  

The Impact of Reusing Cooking Oil

According to the book "Diet & Nutrition, A Holistic Approach," the process of overheating or reusing oil leads to changes in its fats, causing polymerisation. This alters the structure of the fat molecules and forms new compounds that are less beneficial to the body. In some cases, these compounds can even be harmful. 

Also Read: Olive Oil, Coconut Oil Or Canola Oil: Which One Is The Healthiest Cooking Oil? Find In This Video)

Leftover oil is often reused in cooking.
Photo Credit: iStock

Effects On The Health: 

Nutritionist Dr Anju Sood advises against reusing cooking oil, highlighting that it turns rancid and increases the levels of trans-fatty acids, which are highly detrimental to health." Cold-pressed oils, in particular, should be avoided when reheating, as they have low smoking points. The act of reusing oil generates harmful free radicals that can have long-term negative effects on the body. Additionally, reusing oil has been linked to elevated levels of bad cholesterol, which can contribute to arterial blockage and heart disease. 

Trans fats, the most hazardous type of fats, can enter the body through various means. When oil is overcooked or reused multiple times, the level of trans fats present in the oil increases. This poses a significant risk to cardiovascular health and can lead to heart disease.  

The Food Safety and Standards Authority of India (FSSAI) states that repeated frying of oil leads to unfavourable changes in its physiochemical, nutritional, and sensory properties. Total Polar Compounds, formed during frying, can have adverse effects on health.  

Cooking Oil: To Reuse or Not? 

According to health experts and regulatory bodies, it is best to discard the oil used once for frying. It should ideally not be used for other purposes like sauteing as well. But, if you must reuse it to avoid wastage or for other reasons, following these tips will reduce its negative impact on our food and our health.  

Watch out for signs of spoilage while frying leftover oil.
Photo Credit: iStock

Safety Measures For Reusing Leftover Oil:

1. FSSAI Regulation: Discard after two uses

• The FSSAI regulation establishes that vegetable oil becomes unfit for use once the Total Polar Compounds exceed 25 per cent.
• Discard cooking oil after it has been used for frying more than two times to protect health and well-being.

2. Avoid heating oil to its smoking point

• Nutritionist Dr Rupali Dutta suggests refraining from heating oil to its smoking point.
• Once the oil reaches the smoking point during frying, repurpose it for other cooking methods like tadka or sauteing.

3. Cool down and filter out food particles

• Allow the oil to cool down after use.
• Filter out any food particles before storing the oil in an airtight glass container.
• Failure to remove particles may cause the oil to turn rancid during subsequent cooking.

4. Store in a cool, dry place and consume within a month

Seal the container tightly to prevent exposure to air and moisture.
Store the container in a cool, dry place away from direct sunlight.
Consume the oil within a month to ensure freshness and quality.

5. Check for signs of oil spoilage

• Regularly check the stored oil for signs of degradation.
• Look for foaming on the surface, a rancid odour, a thick texture, or a dark, murky appearance.
• These signs indicate oil spoilage and it should not be reused if any are present.

6. Smoking before desired frying temperature indicates unsuitability

•  If the oil begins to smoke before reaching the desired frying temperature, it is not suitable for reuse.
•  Smoking oil can release harmful compounds and affect the quality of the food being cooked.

7. Practise moderation

• Use oil in moderation while cooking to minimise the amount of leftover oil.
• Practising moderation reduces the need for reusing oil and helps reduce wastage overall.

Also Read: How To Clean Cooking Oil After Frying - 5 Easy Tips

Reusing cooking oil may seem like a frugal approach, but it poses potential risks to our health. The chemical changes that occur during the reuse of oil can have detrimental effects on our bodies, increasing the levels of trans fats and free radicals. To maintain a healthy lifestyle, it is advisable to use fresh oil for frying whenever possible.  

(This content including advice provides generic information only. It is in no way a substitute for qualified medical opinion. Always consult a specialist or your own doctor for more information. NDTV does not claim responsibility for this information.)