The Skinny on Fat
There is no one fat intake right for everyone; some people thrive on high-fat diets while others fare much better on lower-fat diets. Everyone's optimal macros depend on individual biochemistry and lifestyle and will differ. In all cases, we all need varied fat to survive and thrive. Fat is essential to many critical functions in your body, including energy, insulation, vitamin absorption and storage, and hormone production. The human brain is more than 60% fat!
It might sound counterintuitive, but eating fat can help you lose weight and maintain a healthy weight. It is also beneficial for your heart (and hair, nails, skin, and so many other organs). The most important thing is knowing what kinds of fats to choose. During the fat-free craze that began in the 1980s, a lot of people packed on the pounds. Why? Because the dietary guidelines encouraged us to reduce or eliminate all fats, we missed out on their health benefits. We ended up replacing them with refined carbs (sugar, white bread), which can contribute to insulin resistance, diabetes, estrogen dominance, heart disease, and, yes, weight gain. (Not to be confused with quality whole food, low glycemic, fibrous carbs, which help steady blood sugar levels that prevent insulin resistance, PCOS, diabetes, and PMS-associated mood swings).
Regardless of the amount of fat in your diet, choosing high-quality fats will make all of the difference in how your body processes and uses the fat.
Here's a quick "fat primer" to make sure you're getting enough of the right kinds.
The two main types of unsaturated fats are monounsaturated and polyunsaturated.
Monounsaturated fats raise HDL (good cholesterol) and lower LDL (bad cholesterol). Sources include nuts (i.e., almonds, cashews, and walnuts) and seeds (i.e., sesame and sunflower), and fruits (i.e., olives and avocados).
It's healthiest to eat fats in their whole food form and use a small amount of their oils, including cold-pressed olive oil, extra virgin olive oil, and avocado oil. Most canola oils are highly processed, so use them in moderation. Look for expeller-pressed and non-GMO canola oil. Why? Expeller pressed means the oil is physically squeezed from the seeds, rather than using chemicals that negatively alter the oil's chemistry.
A diet containing monounsaturated fats has been linked with lower cholesterol and less heart disease, and better weight management. Eat a variety of monounsaturated fats to get the most widespread benefits.
The story with polyunsaturated fats is a bit more nuanced.
These fats are found in nuts, seeds, vegetable oils, and fatty fish. They include omega-3 and omega-6 fatty acids. Because our bodies don't make them, we need to get them from food. Bonus: polyunsaturated fats can help lower our total cholesterol level.
Omega-3 fatty acid
It's a worthy goal to incorporate more omega-3s into our diets. These all-star healthy fats fight inflammation, help control blood clotting, and lower blood pressure and triglycerides. Salmon, mackerel, and sardines are all excellent sources. When possible, fresh, wild-caught fish is best, but canned options also pack a punch in the omega-3 department. The American Heart Association suggests eating at least two 3.5-ounce servings of fish each week.
If you're a vegetarian or just don't like the taste of fish, walnuts, and flax, chia and hemp seeds are also good sources. Bear in mind the conversion of plant-based (called ALA) isn't as high in the body as EPA from fish sources.
Omega-6 fatty acid
Omega-6s are found in vegetable oils and many snack foods. The key is the ratio in comparison to omega-3s. The ratio of omega-6s to omega-3s in the typical Western diet is around 10 to 1. Some research suggests that a 2-to-1 and 4-to-1 ratio reduces the inflammatory response in the body and the risk of death from heart disease. While omega-6 fats are essential like omega-3s, it's important not to overdo them. Your body's ability to regulate inflammation depends on a balanced intake of omega-3s and omega-6s. Focus your diet on whole foods and avoid processed foods and oils high in omega-6 fats (i.e., soybean, sunflower, safflower, cottonseed, and corn oils).
To optimize this ratio, you can both check your omega 6 intake (e.g., by avoiding vegetable oil, processed foods, fast food) and raise your omega 3 intake in balance with omega 6 (e.g., through walnuts, salmon, mackerel, herring, flaxseeds, chia seeds, hemp seeds, and grass-fed eggs).
Saturated fat is always a hot topic—a lot of debate in the health world around saturated fat. I'm not going to pick a side. For most people, It's smart to limit these because they increase total cholesterol and LDL and may boost your type 2 diabetes risk. Meat, seafood, eggs, and dairy products are sources of saturated fat, as is coconut oil. Whether the source is animal or vegetable, saturated fat carries the same risks.
But really. Should I eat saturated fat? Some people say yes, and others say no. Help! High-quality saturated fat is an essential part of a healthy diet when consumed as part of whole foods, high-fiber-based food plans, and in balance with other unsaturated fats. Seek out grass-fed/pastured raised meats and dairy or high-quality plant oils (e.g., unrefined coconut) for a healthy dose of saturated fat. And avoid eating them with refined or high-glycemic carbs.
How do trans fats fit into this picture?
In an ideal world, they don't. Trans fats are known to promote inflammation and have been associated with heart disease, stroke, diabetes, and other chronic conditions.
These are the "bad" fats that increase total cholesterol and LDL and also lower HDL. Trans fats are liquid oils bombarded with hydrogen, so they stay solid at room temperature. They're primarily found in processed and fried foods. Food manufacturers can say a product is "trans-fat free" if it contains less than half a gram per serving. But, unfortunately, these small amounts can still add up. Check a product's ingredient list carefully. If you see the words "hydrogenated," "partially hydrogenated or shortening," it contains trans fat. Better to skip it entirely and choose whole foods instead.
My advice in a nutshell: 1. Don't be afraid of fat; eat it. 2. Variety and quality, and moderation are key.