Foods rich in unsaturated fats include fatty fish, nuts, seeds, avocados, and plant-based oils like olive and sunflower oil. These fats come in two main forms: monounsaturated and polyunsaturated. Both play important roles in heart health, and getting more of them while cutting back on saturated fat is one of the most consistently supported recommendations in nutrition science.
Two Types of Unsaturated Fat
Monounsaturated fats are found in high concentrations in olive oil, avocados, almonds, cashews, peanuts, and pecans. These fats have a single bend in their chemical structure, which keeps them liquid at room temperature but lets them solidify slightly when refrigerated. That’s why olive oil gets cloudy in the fridge.
Polyunsaturated fats have multiple bends in their structure and stay liquid even when chilled. They include two essential fatty acids your body cannot make on its own: omega-3 and omega-6. Omega-3s are concentrated in fatty fish, walnuts, flaxseeds, and chia seeds. Omega-6s are abundant in sunflower seeds, corn oil, soybean oil, and safflower oil. Most people get plenty of omega-6 from everyday cooking oils but fall short on omega-3.
Best Fish Sources of Omega-3
Fatty fish deliver omega-3s in their most usable forms, known as EPA and DHA. Your body can put these to work immediately without needing to convert them first. Atlantic mackerel is one of the richest sources, providing about 2.5 grams of combined EPA and DHA per 100-gram serving. Farmed Atlantic salmon comes close at 1.8 grams per 100 grams, and king mackerel delivers about 2.2 grams.
Sockeye salmon provides roughly 1.2 grams per 100 grams, while albacore tuna offers about 1.3 grams. Even canned sardines, which are inexpensive and shelf-stable, contain around 1 gram per 100-gram serving. Herring and trout are also strong choices. Two servings of fatty fish per week is enough to meaningfully increase your omega-3 intake.
Best Plant Sources
Plants deliver omega-3 in a form called ALA, which your body partially converts into EPA and DHA. The conversion rate is low, so you need larger amounts to get a comparable benefit. One ounce of walnuts provides 2.5 grams of ALA. A single tablespoon of chia seeds contains 2.1 grams, and a tablespoon of ground flaxseed provides 1.2 grams. Adding any of these to oatmeal, yogurt, or a smoothie is an easy daily habit.
For monounsaturated fats, avocados are hard to beat. Half a medium avocado contains roughly 7 grams of monounsaturated fat. Almonds, peanuts, and their butters are also excellent sources. Olive oil, the backbone of Mediterranean-style cooking, is about 73% monounsaturated fat by weight.
Cooking Oils and Heat Stability
Not all unsaturated oils behave the same way at high temperatures. Each oil has a smoke point, the temperature where it starts to break down and produce off-flavors. Choosing the right oil for the cooking method matters.
- Refined avocado oil has the highest smoke point at around 520°F (271°C), making it ideal for searing, stir-frying, and grilling.
- Extra virgin olive oil handles moderate heat well, with a smoke point around 374 to 405°F depending on quality. It works for sautéing vegetables, baking, and roasting.
- Refined olive oil tolerates higher temperatures, reaching 390 to 470°F, making it more versatile for frying.
- Flaxseed oil has a very low smoke point of just 225°F (107°C). Use it only in cold applications like salad dressings or drizzled over finished dishes.
Sunflower oil, corn oil, and soybean oil all have moderate-to-high smoke points, so they hold up in most everyday cooking. But they’re predominantly omega-6, so pairing them with omega-3 sources elsewhere in your diet helps maintain balance.
Why Unsaturated Fats Matter for Heart Health
Replacing saturated fat with unsaturated fat lowers LDL cholesterol, the type most strongly linked to plaque buildup in arteries. Current dietary guidelines recommend keeping saturated fat below 10% of your total daily calories and swapping in unsaturated sources where possible. That means choosing olive oil over butter, snacking on nuts instead of cheese, or eating fish in place of red meat a couple of nights a week.
The evidence behind this swap is substantial. The PREDIMED trial, one of the largest studies on diet and heart disease, found that people following a Mediterranean-style diet rich in olive oil and nuts had roughly 30% fewer heart attacks, strokes, and cardiovascular deaths compared to a control group. A per-protocol analysis of the same study found an even stronger effect, with a 58% relative risk reduction among participants who closely followed the diet. The earlier Lyon Diet Heart Study found a 73% reduction in coronary events among heart attack survivors who adopted a similar eating pattern, results so dramatic the trial was stopped early.
These benefits don’t come from a single food. They emerge from a broader dietary pattern where unsaturated fats replace saturated ones across meals, day after day. Even modest improvements in adherence to this pattern matter. Research published in Circulation Research found that every 2-point increase on a Mediterranean diet adherence score was associated with an 11% reduction in cardiovascular disease risk.
Storing Unsaturated Fats Properly
Unsaturated fats are more prone to going rancid than saturated fats because their chemical structure makes them vulnerable to oxygen, heat, and light. When an oil oxidizes, it breaks down into compounds that create unpleasant smells and flavors, a stale, paint-like, or slightly bitter taste that’s easy to recognize once you know what to look for. Rancid oil won’t necessarily make you sick immediately, but regularly consuming oxidized fats is linked to increased inflammation.
To keep your oils fresh, store them in a cool, dark place. Tinted glass bottles help block light. Nut and seed oils with high polyunsaturated content, like flaxseed and walnut oil, should go in the refrigerator after opening and be used within a few weeks. Olive oil is naturally more stable thanks to its antioxidant content, but it still benefits from being kept away from the stove and out of direct sunlight. If an oil smells off or tastes bitter, discard it.
Whole nuts and seeds also contain oils that can oxidize. Storing them in sealed containers in the refrigerator or freezer extends their shelf life considerably, keeping the fats intact and the flavor fresh for months.