Can you spot the difference between a saturated and unsaturated fat? The difference is that a section of the unsaturated fat is missing two hydrogen atoms. With two hydrogen atoms missing, a double bond has formed between two carbon atoms in the chain. Because this fat has a double bond in the middle of it, it is deemed to be not fully 'saturated' with hydrogen atoms.

Thus, it is unsaturated: There is something else about this particular unsaturated fat that I should point out. It is an Omega 3 fatty acid. Which is officially the healthiest molecule in the world. Indeed, you are looking at the substance that cures just about every ailment of mankind. A veritable Beecham's Powder of the early 21st century. Perhaps I should explain exactly what makes this fat an Omega 3 fatty acid. Firstly, it is called a fatty acid because it has a COOH at one end (the acid group). In fact, all fats have this.

Ergo, all fats are fatty acids, and all fatty acids are fats. But fatty acid does sound so much more scientific and clever than fat: Try saying Omega 3 fat: It just does not have the same ring to it. How can a fat possibly be healthy? But an 'Omega 3 fatty acid'... Now you're talking! The 'Omega 3' refers to the position of the double bond. In a diagram, you will notice the double bond is three carbon atoms along from the right-hand end.

This end of a fat is known as the Omega end. The other end is known as the Alpha end. It's a Greek language thing: from alpha to omega, or A to Z. I think it would be useful if I explained four more things about fats. Namely: What, exactly, a polyunsaturated fat is. How to turn a liquid fat into a solid fat (e.g. a 'cholesterol-reducing' spread). How fats are transported and stored in the body. The lack of connection between fats and cholesterol.