When it comes to fat and health, you are not off the hook just because you do not see it when you look in the mirror, according to Gail Underbakke, senior clinical nutritionist in preventive cardiology at the UW-Madison medical school.
To understand how fats affect the human body, it is important to understand what the types of fat are and what foods have them, as well as how they work.
'The great majority of the bad fats that we consume in our culture come from animal fats,' Underbakke said.
She warns that meat and dairy products like cheese, ice cream, sour cream, cream cheese, whole milk and butter are high in saturated fat.
'The type of fat that we eat affects the kind of cholesterol that is in our blood,' Underbakke said.
Every cell in the body needs some cholesterol, and it is essential for proper brain and nerve function. But too much cholesterol clogs arteries, said Bertrum Connell, director of nutrition and dietetics at Loma Linda University in California.
People who eat more saturated fat can have significantly higher blood cholesterol levels, especially the level of low-density lipoproteins, or 'bad cholesterol.' LDL's invade artery walls and to begin building blockages throughout the body.
'A high saturated-fat diet too often results in heart disease, stroke and high-blood pressure, which in turn lead to premature death or disability,' Connell said.
Another bad fat that is mostly found in processed foods is trans fat. Also known as partially-hydrogenated vegetable oils, trans fats are processed by adding hydrogen to the fat molecule, said Connell. Candy bars, chips and many fast foods contain trans fats.
'The trans fats have a physical form that makes it easier for the fats to lodge in the arteries of the circulatory system,' he said.
On the other hand, good fats are those mostly found in plant-based foods and include monounsaturated and polyunsaturated fats.
Unlike saturated fat, unsaturated fats do not increase LDL cholesterol levels. Replacing saturated fat with unsaturated fats in your diet can help maintain higher levels of high-density lipoprotein cholesterol, said Underbakke.
HDL's, or 'good cholesterol,' sweep excess cholesterol out of cells and back to the liver where they are broken down to be removed from the body. Yet, there are other benefits to the good fats.
'To some degree, monounsaturates can reverse the deposits of plaque in the arteries that have formed through the use of saturated fats and otherwise high-fat diets,' Connell said.
Foods such as nuts and avocados, as well as olive and canola oils, are high in monounsaturated fats. These are excellent foods to include in meals, as they can protect against the development of heart disease, stroke and high blood pressure, Connell said.
Polyunsaturated fats are found in corn, soybean, safflower and sunflower oils.
Then there are essential fatty acids. Omega-3 and omega-6 fatty acids improve health by affecting how sticky the platelets are in the bloodstream and decreasing the likelihood of the blood to clot. The presence of omega-3s in the diet lower the level of general inflammation in the body, which in turn reduces heart disease, Underbakke said.
Fish, such as salmon and mackerel, contain a lot of omega-3s. They are also found in plant sources such as flax seed oil, Underbakke said.
'The most important concept about fat is that you shouldn't fear it,' she said. '[I]f we can build it in with moderation we can have it without necessarily gaining too much weight or harming our cholesterol.\
