Distinguishing the goods fats from the bad fats, in the food we eat, gets easier when you have a basic understanding of their various types.
In order to do this, it’s important to know what the ‘saturation of a fat’ means. The term ‘saturation’ essentially refers to the way a fat reacts to heat and other substances like light and oxygen. The higher the fat’s saturation, the higher its resistance to these factors.
When fat is subjected to factors beyond its resistance point, it spoils or goes rancid, and produces free radicals that can wreak havoc once ingested, in addition to other harmful compounds. Some fats can go past their resistance point even at room temperature, and subjecting those to heat would catapult the entire process to a significantly larger extent.1
Choosing a fat with higher saturation is, thus, better for cooking, since it can withstand higher temperatures.1 Foods usually have a mix of fats as their fat content, so it’s their predominant fat that we must consider.
I: Unsaturated Fats
These are referred to as “good fats” because they benefit our health in many ways. Unsaturated fats fall into two categories:
(i) Monounsaturated Fatty Acids (MUFAs):
You may have heard that the Mediterranean diet is one of the healthiest in the world. If this is true, it’s largely because of its copious use of olive oil, which has a high amount of MUFAs.2
Research shows that MUFAs may reduce the level of insulin in our blood and help control our blood sugar. That’s incredibly helpful for preventing as well as treating type-2 diabetes.3 MUFAs even reduce bad cholesterol, and consequently lowers the risk of heart disease.
(ii) Polyunsaturated fatty acids (PUFAs):
Omega-3 and omega-6 fatty acids are polyunsaturated fatty acids. Both affect our body in completely different ways: omega-3 curbs inflammation, while omega-6 is pro-inflammatory. These opposing forces, in the correct proportion, are critical to the smooth functioning of our immune system.
They’re also very helpful when it comes to several processes of the body. For example, omega-3 fatty acids maintain our skin’s water content, keeping it hydrated. Even more impressively, an omega-3 fatty acid called DHA makes up the structures within our eyes and brain; it essentially plays a role in a range of functions from vision and cognition, to even helping us handle anxiety better. And, just like MUFAs, PUFAs also reduce bad cholesterol and the risk of heart disease.
So what’s the difference between the two? In short, one’s great for cooking and the other isn’t.
“Mono” comes from the Greek word “monos” which means “one”. That’s an easy way to remember that only one part of a MUFA molecule is unsaturated. This makes MUFAs highly resistant to heat and other factors.
Similarly, “poly”-unsaturated means that its molecules are mostly unsaturated – that’s why polyunsaturated fats like omega-3 fats (as found in flaxseed oil) can’t be used for cooking, and must even be stored in dark bottles in the fridge.
II: Saturated Fats
As we know, saturated fats are chemically less reactive and less sensitive to heat, which makes them ideal for cooking. Coconut oil and ghee are classic examples of saturated fats.
For a very long time, though, these fats were mistakenly believed to cause heart disease. Studies have only recently vindicated saturated fats, even going on to prove that they help our cardiovascular system by:
- Increasing levels of HDL – the good cholesterol – in the blood.4
- Making LDL – the bad cholesterol – turn into a larger form that isn’t associated with heart disease (unlike its smaller form).5
- Providing vitamin K2, which reduces the risk of heart disease and osteoporosis as it helps the body use calcium.6
Even though saturated fats clearly aren’t all bad, they’re mainly healthy in small quantities. Try limiting your consumption of them to about 6-10% of your daily calorie intake.
Note: You can calculate this by remembering that all fats have 9 calories per gram. So if you’d like to calculate how much a cup of milk, for example, contributes to the amount of saturated fats you can have in one day, first check how much saturated fat your brand of milk has (read through the food label).
Generally, a cup of milk will have around 1.5 g of saturated fat. Assuming yours does, too, 1.5 g x 9 calories/gram = 13.5 calories. Assuming you consume 2000 calories per day, this cup of milk accounts for about 0.67% of your allowance.
III: Trans Fats
Natural trans-fats are found in dairy products – these are called ruminant trans-fats. The most well-known one, conjugated linoleic acid (CLA), is believed to be good for our health, when consumed in moderation.7-11
But there’s an artificial kind of trans-fat that’s bad for us even in small quantities.
Unsaturated fats turn into artificial trans-fats when they’re overheated. They’re also intentionally turned into artificial trans-fats when they’re used in processed foods, to give them a longer shelf-life.12
Here’s why that’s a bad thing:
- Trans-fats significantly increase “bad” LDL cholesterol (even when they make up just 1% of your total calories), but do not increase HDL “good” cholesterol. This raises the risk of heart disease.14
- Trans-fats activate the immune system unnecessarily, which makes it attack healthy tissue. Too much of this, over time, is the underlying cause of many ‘lifestyle diseases’, like metabolic syndrome, diabetes, arthritis and numerous others.15, 16
That’s why fried food is best avoided, if the oil is heated beyond its smoke point.
Identifying the Types of Fats
An easy way to identify the predominant fat in a food is by simply seeing its state at room temperature: unsaturated fats are liquid (most oils are examples of this), whereas saturated fats are solid (like butter, ghee and coconut oil).
But here’s where things could get confusing: artificial trans-fats are also solid at room temperature.
They’re generally found in processed foods, with the words “hydrogenated” and “shortning” highlighting the fact that the product has trans-fats. In fact, “partially hydrogenated oils” are the primary dietary source of artificial trans-fats. A good way to identify their presence is by simply looking out for these words in the ingredients list. Keep in mind that even products that do have trans-fats can claim to have “zero trans-fats” on the label, if the amount is less than 0.5 grams– so, again, make sure you look for the words “hydrogenated” and/or “shortning” at the back of the pack.13
Fats make up a significant part of our daily nutritional needs as well as consumption. Understanding their proven health benefits can go a long way in helping us lead overall healthier lifestyles.
References:
1. Prabhu HR. Indian Journal of Clinical Biochemistry 2000, 15(1): 1-5.
2. Martínez-González M, Sánchez-Villegas A. European Journal of Epidemiology 2004, 19(1): 9-13.
3. Riccardi G, et al. Clin Nutr 2004, 23(4): 447-456.
4. Mensink RP, et al. Am J Clin Nutr 2003, 77(5): 1146-1155.
5. Dreon DM, et al. Am J Clin Nutr 1998, 67(5): 828-836.
6. Vermeer C, et al. Eur J Nutr 2004, 43(6): 325-335.
7. Gaullier JM, et al. Am J Clin Nutr 2004, 79(6): 1118-1125.
8. Hur SJ, Park Y. Eur J Pharmacol 2007, 568(1-3): 16-24.
9. Lehnen TE, et al. J Int Soc Sports Nutr 2015, 12: 36.
10. Lin H, et al. J Dairy Sci 1995, 78(11): 2358-2365.
11. Syvertsen C, et al. Int J Obes (Lond) 2007, 31(7): 1148-1154.
12. Dijkstra AJ, et al. Trans Fatty Acids. Wiley, 2008.
13. FDA. A Food Labeling Guide (10. Appendix B: Additional Requirements for Nutrient Content Claims).
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