The Skinny on Fat: A Little Background

Trans-fats, poly-unsaturated fats, fish oil, olive oil, canola oil, omega 3 fatty acids, margarine, and butter: Who the heck can keep track of all the different kinds of fats out there? Some, they say, cause high cholesterol and others reduce it? Some say to avoid it all together?

There are few subjects as complicated, or contravertial, in the field of nutrition as the topic of fat. But to really understand the subject, we’re going to have to have a little crash course in biochemistry.

Ok well first off, what is fat? Well besides it being the stuff that comprises your luv handles and beer belly, fats (AKA lipids if you’re into your biochemistry terms) are one of the macro nutrients that provide calories from the food we eat; the other two being carbohydrates and protein. Fats can be found in two forms in nature, liquid and solid. Oils are the liquid form at room temperature; butter and lard are solid at room temperature.

What about cholesterol you ask? Good question! When the subject of fat comes up, inevitably the subject of cholesterol soon follows. But the thing is cholesterol is not a fat, it actually belongs to a sub-group of steroids called sterols. Sterols are vital for the body’s cell production process, as well as in vitamin and hormone production. Think of athlete’s who use steroids to build muscles; the steroids they are using are specific for the generation of muscle cells. These same athletes have increased testosterone levels, due to stimulated production of that hormone, leading to side effects such as increased acne and “roid rage.”

OK, well here’s where it gets a little complicated. Fats circulate through our bodies by combining with proteins to create vehicles called lipoproteins. Perhaps you’ve heard of LDL and HDL: Low Density Lipoprotein and High Density Lipoprotein?  These fat transport vehicles also pick up cholesterol, to form LDL and HDL (among a few other compounds we won’t get into right now). LDL, the “bad cholesterol” carries cholesterol from the liver back to the body cells. The “good cholesterol,” HDL, picks up the cholesterol from the body and brings it back to the liver so it can be eliminated.

Got it so far? So when you get a blood test to test your cholesterol level, your doctor is checking for the amount of these lipoproteins circulating in your blood stream. Optimally you want low levels of LDL, and high amounts of HDL to protect you from coronary artery disease and heart disease. We’ve been told that when your cholesterol levels are good, then you’ll be safe from heart attacks. So reduce your intake of fat and cholesterol and you’ll be fine. But there’s something seriously wrong with this theory, since a majority (some sources claim as high as 75%) of patients hospitalized with heart attacks have normal cholesterol levels. Yup, there’s a serious piece missing here.

So that’s a little biochemistry background for you to get started. Next we’ll delve into how the fat you consume affects these biochemical pathways.