Fatty acid primer
A quick guide to how the carbon bonds in fatty acids can be arranged
Saturated fat molecules (below, left) do not contain double bonds between their carbon atoms, while unsaturated fat molecules (below, right) contain one or more double bonds between their carbon atoms.

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‘Big Picture: Fat’ (2015)
In unsaturated fats, the cis configuration is usual. In trans fats, some bonds are flipped.

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‘Big Picture: Fat’ (2015)