Damaged fat: letting good fats turn bad
A good fat can become bad if it gets damaged by heat, light or oxygen. Poly-unsaturated fats are the most fragile. Oils that are high in poly-unsaturated fats (such as flax seed oil) must be refrigerated and kept in a dark container. Cooking with these oils also damages the fats. Never use oils, seeds or nuts after they begin to smell or taste rank or bitter.
The worst fats: Trans fats (trans-fatty acids - TFA)
A trans fat is a normal fat molecule that has been twisted and deformed during a process called hydrogenation. During this process, liquid vegetable oil is heated and combined with hydrogen gas. No amount of trans fats is healthy - if your diet doesn’t contain enough good fat, your body will use the deformed trans fats instead, which could possibly contribute to major health risks from heart disease to cancer.
So why are trans fatty acids (TFAs) so prevalent in commercial foods? Partially hydrogenated oils (what comes out of the hydrogenation process) are more stable (less likely to spoil), can be transported more easily, and can withstand repeated heating, which makes them perfect for frying up those French fries and burgers at your favorite fast food establishment.
Trans fats may be found in foods like:
- Baked Goods -- cookies, crackers, cakes, muffins, pie crusts, pizza dough, and some breads like hamburger buns
- Fried foods -- doughnuts, French fries, fried chicken including chicken nuggets, and hard taco shells
- Snack foods -- potato, corn, and tortilla chips; candy; packaged or microwave popcorn.
- Solid fats -- Hard margarine (stick margarine) and semi solid vegetable shortening.
- Pre-mixed products -- cake mix, pancake mix, and chocolate drink mix.
TFAs tend to raise total LDL (bad) cholesterol levels and lower HDL (good cholesterol). This can contribute to major health problems, from heart disease to cancer. No amount of trans fat is healthy, and should be kept below 1 percent of your total calories.
Be a trans fat detective
Use your own investigative skills to avoid trans fats:
When shopping, read the labels and watch out for “partially hydrogenated oil” in the ingredients. Even if the food claims to be trans fat free, this ingredient tells you that the product is a trans fat suspect.
When eating out, put fried foods, biscuits, and other baked goods on your “skip” list. Avoid these products unless you know that the restaurant has eliminated trans fat
Most states have no labeling regulations for fast food, and it can even be advertised as cholesterol-free and cooked in vegetable oil. Eating one doughnut at breakfast (3.2 g of TFA) and a large order of french fries at lunch (6.8 g of TFA) adds 10 grams of TFA to one's diet, according to the American Heart Association.