Good fats are unsaturated fats, specifically monounsaturated and polyunsaturated fats. These are the fats found in foods like olive oil, avocados, nuts, seeds, and fatty fish. Unlike saturated and trans fats, which raise harmful cholesterol levels, unsaturated fats lower it, reduce inflammation, and support everything from brain function to hormone regulation. Current dietary guidelines recommend that 20 to 35 percent of your daily calories come from fat, with most of that coming from unsaturated sources.
Monounsaturated vs. Polyunsaturated Fats
Unsaturated fats come in two forms, and the difference is in their molecular structure. Monounsaturated fats have one flexible bend in their carbon chain, while polyunsaturated fats have two or more. Those bends prevent the molecules from packing tightly together, which is why these fats are liquid at room temperature (think olive oil) rather than solid (think butter). Both types are beneficial, but they show up in different foods and serve slightly different roles in your body.
Monounsaturated fats are concentrated in avocados, olives, almonds, hazelnuts, pecans, peanuts, and oils like olive, canola, and peanut oil. Polyunsaturated fats include the omega-3 and omega-6 fatty acids found in fatty fish, walnuts, flaxseeds, and oils like safflower and sunflower. You don’t need to choose between the two. A healthy diet includes both.
How Good Fats Protect Your Heart
The most well-established benefit of unsaturated fats is their effect on cholesterol. Both monounsaturated and polyunsaturated fats lower LDL cholesterol, the type that builds up in artery walls. They do this by increasing the number of LDL receptors in your liver, which pulls more LDL out of your bloodstream and breaks it down faster. The net effect is less cholesterol circulating where it can cause damage.
U.S. dietary guidelines recommend keeping saturated fat below 10 percent of your daily calories and replacing it with unsaturated fats, particularly polyunsaturated fats. On a 2,000-calorie diet, that means no more than about 22 grams of saturated fat per day, with the rest of your fat intake coming from healthier sources.
Omega-3s and Inflammation
Among the polyunsaturated fats, omega-3 fatty acids deserve special attention. Your body uses omega-3s to produce compounds called resolvins and protectins, which actively calm inflammation and help tissues return to a healthy baseline. Omega-6 fatty acids, by contrast, tend to promote inflammation as part of the immune response. Both are necessary, but the balance matters.
For most of human history, the ratio of omega-6 to omega-3 in the diet was roughly 4 to 1 or lower. Today, thanks to processed seed oils in packaged food, that ratio has ballooned to about 20 to 1 in many Western diets. This imbalance fuels chronic, low-grade inflammation linked to heart disease, autoimmune conditions, and allergies. The practical fix is straightforward: eat more omega-3-rich foods (salmon, sardines, mackerel, walnuts, flaxseeds) and fewer ultra-processed foods heavy in omega-6 oils.
Clinical trials back this up. In one controlled study of severely obese patients, omega-3 supplementation significantly decreased circulating levels of a key inflammatory marker (interleukin-6), reduced triglycerides, and shifted gene expression in fat tissue away from inflammation. These weren’t small, subtle changes. The treatment also boosted production of anti-inflammatory compounds in both deep and surface-level body fat.
Why Your Brain and Hormones Need Fat
Essential fatty acids are structural building blocks of every cell membrane in your body, but the brain, retina, and nervous system are especially rich in long-chain polyunsaturated fats. These fats are critical for building and maintaining the insulating sheath around nerve fibers that allows signals to travel quickly between neurons. Without adequate dietary fat, this insulation degrades, slowing communication throughout the nervous system.
Fat also plays a role in hormone production. Long-chain polyunsaturated fatty acids regulate gene expression through a family of nuclear receptors related to steroid hormone receptors. In plain terms, healthy fats help your body read its own genetic instructions for producing hormones that regulate metabolism, stress response, and reproduction. This is one reason extremely low-fat diets can disrupt menstrual cycles and leave people feeling mentally foggy.
Fat Helps You Absorb Vitamins
Vitamins A, D, E, and K are fat-soluble, meaning they dissolve in fat rather than water. Without enough fat in a meal, these vitamins pass through your digestive system largely unabsorbed. Research suggests that fat intake should not fall below about 10 percent of total calories to ensure reliable absorption of fat-soluble vitamins, particularly A and E. In practical terms, drizzling olive oil on a salad or eating avocado alongside vegetables isn’t just about flavor. It’s how your body actually captures the nutrients in those foods.
Best Food Sources of Good Fats
You can get plenty of healthy fat without supplements. The richest everyday sources of monounsaturated fats include:
- Avocados
- Nuts such as almonds, hazelnuts, pecans, and peanuts
- Seeds like pumpkin and sesame
- Olives and olive oil
- Canola and peanut oils
For polyunsaturated fats, especially omega-3s, focus on fatty fish (salmon, sardines, mackerel, herring), walnuts, flaxseeds, chia seeds, and their oils. Two to three servings of fatty fish per week is a common benchmark for getting enough EPA and DHA, the two omega-3 forms your body uses most directly.
Cooking with Healthy Oils
Not every healthy oil works at every temperature. Each oil has a smoke point, the temperature at which it starts to break down and produce off-flavors. Choosing the right oil for the job keeps your food tasting good and preserves the oil’s beneficial properties.
For high-heat cooking like searing, stir-frying, or roasting above 400°F, refined avocado oil is the standout with a smoke point of 520°F. Light (refined) olive oil handles about 450°F, and refined peanut, canola, and safflower oils all work well around 435 to 450°F. These refined oils have had some flavor compounds removed, which makes them more heat-stable.
Extra-virgin olive oil has a lower smoke point of around 374°F because it retains all those flavorful compounds that burn at moderate temperatures. It’s ideal for sautéing over medium heat, finishing dishes, and making dressings. Unrefined coconut and sesame oils smoke at about 350°F, making them better for gentle cooking or baking. Unrefined peanut oil drops even lower, to 320°F.
A practical approach: keep a refined high-heat oil (avocado or light olive) for frying and roasting, and a bottle of extra-virgin olive oil for everything else. That covers most cooking situations while keeping your fat intake squarely in the “good” category.