Whether you leave oil in the sun or fry food in it, the same bad chemicals form — just at different speeds.

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Evidence from Studies

Supporting (1)

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Analysis of the Generation of Harmful Aldehydes in Edible Oils During Sunlight Exposure and Deep-Frying Using High-Field Proton Nuclear Magnetic Resonance Spectroscopy

Cross-Sectional Study

In Vitro

2025 Feb 5

Contradicting (0)

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No contradicting evidence found

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Source Study

Analysis of the Generation of Harmful Aldehydes in Edible Oils During Sunlight Exposure and Deep-Frying Using High-Field Proton Nuclear Magnetic Resonance Spectroscopy

Score: 6

DOI: 10.3390/foods14030513

Similar Assertions

Oils with more unsaturated fats (like sunflower and sesame) break down faster and make more harmful chemicals when heated or left in the sun than oils with more saturated fats (like peanut or olive).

78%

When you fry potato chips over and over in sunflower oil at a medium heat, harmful chemicals build up in the chips — but if you use a special oil called MRAFO, those chemicals barely form at all, even after frying many times.

71%