We’ve been covering fat synthesis in biochemistry the last few weeks, and it’s been interesting to learn how various dietary changes will affect how much fat a person makes.
First of all; we need fats! They make up our cell membranes, hormones, neural tissue and allow us to store energy. Most of the fatty acids we store (as triglycerides in our fat cells) actually come from the sugars we eat. After breaking down a sugar molecule, some of the byproducts will be shunted to a new enzyme complex to be made into fatty acids. This process is enhanced by insulin, the hormone our bodies release when we’ve eaten sugars. Once the fatty acids are made, they are attached to a glycerol backbone and transported to fat cells for storage.
This system makes a lot of sense for us, since in human natural history we generally haven’t had an overabundance of food - so storing extra energy for later would allow us a safety margin between meals. Our brain and muscles use an incredible amount of energy, and being able to fuel these systems with stored reserves of fat is hugely important. Of course, now that we don’t have to hunt and gather our food, this energy storage mechanism can work against us if we over-eat sugary (or fatty) items. But the fact that we can eat ‘fat-free’ foods and still synthesize fat molecules shows us how important fats really are for a healthy body!