The Oil Change Your Body Deserves: Why Switching Oils Can Save Your Health and its importance.

Introduction: 

Cooking oil is one of the most widespread components of our daily diets. Nearly every dish we prepare whether sauteed vegetables, deep-fried snacks, or curries contains oil as an essential ingredient. While oil adds flavour and energy, the type of oil we use and how we use it deeply influences our long-term health. Scientific evidence shows that not all fats are created equal: some support heart and metabolic health, while others can contribute to chronic diseases when over-used or repeatedly heated. Understanding these differences and how to apply them in everyday cooking empowers healthier choices at the household level. 

1. Understanding Saturated vs. Unsaturated Fats: 

Fats in oils are made up of molecules called fatty acids. These come in two major types: 

Saturated Fats 

Structure: Fatty acids are “saturated” with hydrogen atoms with no double bonds. 

Physical trait: They are typically solid at room temperature (e.g., butter, ghee) and often more stable during heating. 

Common sources: Coconut oil, palm oil, animal fats. 

Health effects: Diets high in saturated fats tend to raise “bad” LDL cholesterol levels, which is associated with higher risk of heart disease and metabolic issues. Replacing saturated with unsaturated fats is linked with better health outcomes. 

Unsaturated Fats 

Structure: They have one (monounsaturated) or more (polyunsaturated) double bonds in their fatty acid chains. 

Physical trait: They remain liquid at room temperature (e.g., olive, canola oil). 

Health effects: Unsaturated fats help lower LDL cholesterol and are associated with reduced risk of cardiovascular disease and mortality when replacing saturated fats in the diet.  

In everyday kitchen terms: 

Saturated fats are like heavy, solid grease good in small amounts but can “clog the pipes” of your blood vessels if too much is used. Unsaturated fats are lighter, more fluid oils that help keep those pipes clear and flexible. 

2. Everyday Cooking Oils: What They Are & How They Differ: 

Here are common household oils and how their fat composition influences their health effects: 

Olive Oil: 

• Rich in monounsaturated fats, especially oleic acid. 

• Unsaturated composition supports heart health and lower LDL cholesterol.  

Canola Oil: 

• High in monounsaturated fats and some polyunsaturated fats (omega-3 and omega-6). 

• Favourable fat profile for replacing saturated fats. 

Sunflower & Corn Oils 

• High in polyunsaturated fats (especially omega-6). 

• Often recommended for heart health when fresh and not overheated repeatedly.  

Coconut and Palm Oils 

• High in saturated fats. 

• More stable at high heat but should be used with moderation due to potential LDL effects.  

• Even within one type of oil, fatty acid composition influences oxidation rate (how quickly it degrades with heat and over time).  

• Oils richer in unsaturated fats tend to oxidize faster when heated and stored for long periods, which is why freshness matters.  

3. Why Changing Cooking Oil Matters for Health 

A. Oxidation & Oil Quality Degradation 

When oils are stored or reused repeatedly especially with heat, they undergo oxidation. This is a chemical process where fats react with oxygen, leading to breakdown products such as peroxides and aldehydes. These compounds can: 

• Damage cellular structures, 

• Increase oxidative stress, 

• Promote inflammation, and 

• Impair heart and metabolic health.  

Think of oxidation like rust forming on metal the longer you leave it exposed, the more degraded it gets. Similarly, old or repeatedly heated oil becomes less healthy and more harmful. 

B. Repeated Heating Creates Toxic Compounds 

Scientific studies show that re-heating cooking oil multiple times as often happens in households or street food settings significantly alters the oil’s chemistry and produces toxic substances. These include aldehydes and other oxidation by-products associated with chronic diseases such as heart disease and cancer.

In simple terms: 

Every time oil is heated and reused, its structure breaks down, nutrients are lost, and harmful compounds accumulate burdening your body’s detox systems and increasing disease risk. 

C. Why Monthly Oil Change Is Recommended 

From a nutrition perspective, changing oil monthly (roughly ~500 ml per person per month) helps ensure the oil used in cooking is: 

• Fresh and less oxidized, 

• Higher in beneficial unsaturated fats, and 

• Lower in toxic breakdown products. 

Dietitians recommend this cycle because oils gradually lose beneficial compounds and gain harmful ones with time and heat exposure. While exact scientific consensus on “one month” is still evolving, the underlying biochemical reasoning oxidation over time and with heat is clear.  

4. Practical Tips for Better Health : 

• Use oils with healthier fat profiles (olives, canola) most often. 

• Avoid excessive reuse or reheating of the same oil (fresh is better). 

• Replace oils regularly (about monthly for typical household use). 

• Store oil in a cool, dark place to slow oxidation and rancidity. 

• Match oil type to cooking method (high smoke point oils for frying, delicate oils for salads/dressings). 

What Should We Do in Our Kitchens and Food Policies? 

At the Household Level (Simple, Practical & Science-Backed) 

1. Choose the right oil for the right purpose  For everyday cooking, extra-virgin olive oil (EVOO) is one of the best choices for salads, dressings, and low-to-moderate heat cooking. Research shows that EVOO supports heart health not just because of its healthy fats, but also due to natural plant compounds called polyphenols, which reduce inflammation and oxidative stress in the body.  When higher-heat cooking (deep-frying or prolonged sautéing) is needed and EVOO is not practical due to cost or availability, high-oleic sunflower oil or rice bran oil can be used. These oils are richer in more heat-stable unsaturated fats, making them safer options for higher temperatures.  In simple terms: Use lighter, antioxidant-rich oils for everyday cooking and more heat-stable oils only when necessary. 
   

   

2. Avoid industrial trans fats completely  Partially hydrogenated oils  often found in bakery items, packaged snacks, and fried foods  contain industrial trans fats, which are strongly linked to heart disease and early mortality. These fats damage blood vessels, raise bad cholesterol, and increase inflammation.  Dietitian’s advice: Even small amounts of trans fats are harmful. Avoid foods listing “partially hydrogenated oils” on labels and limit heavily processed foods.
   

3. Never reuse frying oil repeatedly  Reusing oil multiple times or heating it for long hours causes chemical breakdown. This produces oxidized fats and toxic compounds, which burden the liver, increase inflammation, and may raise the risk of chronic diseases. Fresh oil nourishes the body. Overused oil behaves like burnt fuel it harms more than it helps. 
   

4. Change oil regularly don’t wait until it looks bad  Dietitians often recommend around 500 ml oil per person per month and encourage changing oils regularly. Over time, oil loses beneficial nutrients and accumulates harmful by-products, even if it looks “okay.” 

   Discard oil immediately if it shows: 

   ● Dark colour 

   ● Thick or sticky texture 

   ● Low smoke point (smokes quickly) 

   ● Unpleasant smell 

   Health logic: Regular oil replacement reduces exposure to degraded fats and supports better heart, liver, and metabolic health. 

Summary: 

• Choosing and using cooking oil wisely is not just a culinary preference it affects your cholesterol, inflammation, oxidative stress, and long-term disease risk.  

• Unsaturated fats from plant oils can improve heart health and longevity when they replace saturated fats in the diet.  

• Oils degrade chemically when heated and stored, leading to harmful oxidation products that can increase risk of chronic diseases. 

• Changing oil frequently at the household level helps ensure fresh oil with fewer toxic compounds and better nutrient quality. 

• Every drop of oil used daily is an opportunity to support your body’s health or detract from it. Making informed choices, rooted in science, gives your body the oil change it deserves. 

Reference: 

• Li, Y., et al., 2015. Saturated Fat as Compared With Unsaturated Fats and Health Outcomes. 

• Petersen, K. S., 2024. Health Effects of Unsaturated Fatty Acids and Plant Oils.  

• Gharby, S., et al., 2025. Vegetable Oil Oxidation: Mechanisms, Impact on Quality. Science direct.  

• Falade, A. O., et al., 2017. Potential Health Implications of Thermally Oxidized Cooking Oils. Polish Journal of Food and Nutritional Sciences.  

• Mishra, S. et al., 2023. Effect of Repeated Heating on Cooking Oils.