Unsaturated fats are considered beneficial fats because they can improve blood cholesterol levels, ease inflammation, and stabilize heart rhythms, and play a number of other beneficial roles.
Unsaturated fats are monounsaturated and polyunsaturated
Monounsaturated fats are found in high concentrations in:
Olive, peanut, and canola oils
Avocados
Nuts such as almonds, hazelnuts, and pecans
Seeds such as pumpkin and sesame seeds
Polyunsaturated fats are found in high concentrations in:
Sunflower, corn, soybean, and flaxseed oils
Walnuts
Flax seeds
Fish
Omega-3 fats are an important type of polyunsaturated fat. The body can’t make these, so they must come from food. An excellent way to get omega-3 fats is by eating fish.
Good plant sources of omega-3 fats include flax seeds, walnuts, and canola or soybean oil.
EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) – both are long chain omega 3 fatty acids, and both come from animal sources. DHA keeps the nervous system functioning and provides anti-inflammatory benefits. Higher consumption correlates with improved mood, greater insulin sensitivity, increased muscle growth, and better sleep.
ALA (alpha-linolenic acid) – is a short chain omega 3 fatty acid. ALA comes mostly from plant sources, and most animals can’t really use it, so they convert it to DHA.
Omega 3s are an integral part of cells membranes throughout the entire body and affect the cell receptors in these membranes. Omega 3s also help make hormones that regulate blood, heart, and genetic function. Studies show that omega 3s help prevent heart disease and stroke, may help control lupus, eczema, and rheumatoid arthritis, and may protect against cancer. (
https://www.hsph.harvard.edu/nutritionsource/omega-3-fats/)
Saturated Fats
All foods containing fat have a mix of specific types of fats. Saturated fat is mainly found in animal foods, but a few plant foods are also high in saturated fats, such as coconut, coconut oil, palm oil, and palm kernel oil.
In the United States, the biggest sources of saturated fat in the diet are:
Pizza and cheese
Whole and reduced fat milk, butter and dairy desserts
Meat products (sausage, bacon, beef, hamburgers)
Cookies and other grain-based desserts
Mexican fast food dishes
(Institute, N.C., Risk Factor Monitoring and Methods: Table 1. Top Food Sources of Saturated Fat among U.S. Population, 2005–2006. NHANES)
Trans Fats
Trans fatty acids are made by heating liquid vegetable oils in the presence of hydrogen gas and a catalyst, a process called hydrogenation.
Trans fats are also naturally found in beef fat and dairy fat in small amounts.
Partially hydrogenating vegetable oils makes them more stable and less likely to become rancid. This process also converts the oil into a solid, which makes them function as margarine or shortening. Partially hydrogenated oils can withstand repeated heating without breaking down, making them ideal for frying fast foods. For these reasons, partially hydrogenated oils became a mainstay in restaurants for frying, baked goods, and processed snack foods and margarine.
Trans fats are worse for cholesterol levels than saturated fats because they:
Raise bad LDL and lower good HDL
Create inflammation - a reaction related to immunity – which has been implicated in heart disease, stroke, diabetes, and other chronic conditions and contribute to insulin resistance.
(Riserus, U., W.C. Willett, and F.B. Hu, Dietary fats and prevention of type 2 diabetes. Prog Lipid Res, 2009. 48(1): p. 44-51.) (Mozaffarian, D., et al., Dietary intake of trans fatty acids and systemic inflammation in women. Am J Clin Nutr, 2004. 79(4): p. 606-612.)
Different types of fat behave differently in your body. Most of those differences come down to the molecular structure and the stability of the fat. The stability of a fat largely depends on how many binding sites it has open. Fats with fewer open binding sites are more stable (they’re less likely to let a free radical oxidize them by stealing an electron). Oxidized fats speed up aging and create inflammation.
In saturated fats, all the binding sites are filled (“saturated”).
Monounsaturated fats are relatively stable, but they’re not quite as stable as saturated fats. “Mono,” meaning one, indicates that there is one place for a free radical to enter.
Polyunsaturated fats are the least stable fats. They have multiple binding sites exposed, making them particularly open to oxidation.
Liquid fats come from plant oils and are unsaturated fats. Olive, canola, corn, soybean, safflower and sesame oils all come from plants. One exception of a liquid fat not from plants is fish oil.
Fats that are solid at room temperature come from animals and are saturated fats
