The secret's out that not all fats are equal. Some are good, some are bad. But deciphering what's what is a little more complicated for the average Joe or Jane. So here's a simple breakdown on the basics.

Fats, or lipids, are water-insoluble molecules that are an essential part of our body structure and many bodily processes including proper brain function. Every cell in our body has an outer membrane (phospholipid bilayer) that is part fat to help maintain a barrier between the cell's insides and the rest of our bodily fluids. Without turning this into a chemistry lesson, let's just say that each molecule of fat contains a chain of carbon and hydrogen atoms bonded together (fatty acid). Each carbon can bond to multiple hydrogens, so the degree of saturation of the fat molecule depends on how "saturated" the carbons are with hydrogens. The more saturated a fat is, the more solid it can be. Saturated fats, like lard, butter and animal fats are solid at room temperature. Imagine that in your bloodstream. Solid, not fluid, getting stuck in your vessels and clogging things up -- like hair in a drain. Polyunsaturated fats, like in fish oils, remain liquid even at cool temperatures.

Saturated fats (where carbons are fully bonded with hydrogens) are turned into cholesterol by our liver thereby increasing blood levels of LDL (the bad cholesterol). These fats are found mostly in animal meats and products including dairy, coconut and palm kernel oils, and vegetable shortening. These are the fats we want to avoid.

Cholesterol molecules are transported by LDL and HDL molecules. Low-density lipoproteins (LDL -- the bad kind) carry cholesterol from the liver to body cells whereas high-density lipoproteins (HDL -- the healthy kind) carry cholesterol to the liver for excretion.

Monounsaturated fats have one carbon that is not fully bonded with hydrogens. These fats reduce LDL cholesterol levels while possibly raising HDL cholesterol levels. Find monounsaturated fats in vegetable and nut oils, especially olive, peanut and canola; nuts; seeds (including flasxeeds); avocados; whole grain wheat; and oatmeal.

Polyunsaturated fats have more than one carbon that is not fully bonded with hydrogens. They are abundant in corn, soybean and safflower oils, grains, soybeans, fish and seafood (especially herring, salmon, mackerel, and halibut). The essential fatty acids Omega-3 and Omega-6 (dubbed "essential" because our bodies cannot make them so it is essential we get them from our diet) are polyunsaturated fats. Omega-3's are primarily found in fish oils while Omega-6's are primarily found in plant oils. Remember that even good fats are calorie dense, so don't over do it.

Trans-fats are the worst of all. Imagine fat molecules being shaped like a spoon and stacking nicely together. Well, trans-fats are kinked so that they don't stack nicely. Which means they impair membrane flexibility and proper lipid functioning. They also raise bad cholesterol levels and lower good cholesterol levels. These sticky, inflexible trans-fats are found in animal products. They are also created by the hydrogenation process, hence the mass avoidance of hydrogenated and partially-hydrogenated foods.

Maybe now you can get a little healthier, and even skinner, by choosing your fats wisely.

Jennifer Spaide received her master's degree in human nutrition from Columbia University. She is a mom, personal chef and freelance writer residing in New Canaan. As founder of GreenChic, Jennifer is dedicated to inspiring individuals to get fresh in the kitchen and eat their way to a healthy life. Contact her at 203-247-2002 or jennifer@thegreenchiclife.com. Visit www.thegreenchiclife.com to learn more.