It used to be that the mere mention of the word fat sent health conscious eaters into retreat mode. Fat was to be avoided at all costs, and the lower the amount one consumed, the better. Yet as health and weight problems rose simultaneously with the proliferation of goods such as fat-free salad dressings, light cookies, and low-fat peanut butter, it’s come to light that fat, the much maligned macromolecule, doesn’t deserve the reputation it’s been dealt.

As it turns out, the percentage of fat in our diet doesn’t dictate weight or health. A 2006 study published in the Journal of the American Medical Association found almost identical rates of heart attack, stroke, heart disease, and weight control in women who followed a low-fat diet versus those who didn’t. Other studies have backed this up, finding no correlation between heart disease, cancer, or weight and percentage of fat in diet. What they did find, however, was that it’s not the amount of fat, but rather the type of fat a person eats that makes a difference.

That’s because not all fat is created equal. Some fats, like artificially created trans fats, are clearly deleterious for our health. But others are not only better for us, they are absolutely necessary for good health.

So which fats should be included in our diet and which ones should we avoid?

Go with the Good Ones
The real villain when it comes to fat is trans fat, which is made by partially hydrogenating vegetable oils to make them more stable at room temperature. Trans fat raises the bad kind of cholesterol, LDL, and lowers the good kind, HDL. It’s also been linked to inflammation, heart disease, and other chronic diseases. Although trans fat is found naturally in products like cheese and meats, Americans consume most of their trans fat in the form of fried, packaged, and processed foods. It should come as no surprise that French fries, margarine, processed cookies and crackers, and fast food aren’t good for us.

Saturated fats are also considered “bad” because they, too, raise LDL levels and have been linked with cardiovascular disease. Our bodies are able to make saturated fat, so we don’t need to consume it, but we do, in the form of meat, full-fat dairy products, and some vegetable sources, like coconut and palm oils.

Unsaturated fats, like monounsaturated and polyunsaturated, are fats that are good for us because they play a number of beneficial functions in the body, including lowering cholesterol levels, reducing inflammation, reducing arterial plaque formations, and improving skin tone and texture. One type of polyunsaturated fat, the omega-3 fats, are particularly beneficial for health. Because we can’t make these fats, we must get them from our diet. Studies have shown that omega-3 fats can help with cognition, reduce inflammatory symptoms, and protect the heart.

Incorporating good fats into the diet is easy. They not only keep us satiated, they add a savory flavor to everything they touch.

Vegetables Oils
Most unsaturated oils are vegetable-based, so a good rule in the kitchen is to look for ways you can remove an animal-based saturated fat and replace it with a vegetable-based one. (Make sure you don’t, however, buy products that contain “partially or hydrogenated vegetable oils.” This is where the trans fats come in.) Most fats that are liquid at room temperature are unsaturated. Canola, peanut, and olive oil contain good amounts of monounsaturated fat, while sunflower, corn, soybean, and flaxseed oil contain polyunsaturated fat. Both flaxseed and canola oil contain omega-3s. A good way to switch out saturated fat for healthier fats is to dip bread in olive oil rather than butter, use vegetable oils when sautéing, and use oil in place of butter when baking.

Nuts
Nuts and seeds are another great source of healthy fats and nutrients. Almonds have antioxidants and fiber, walnuts have omega-3s, and peanut butter has monounsaturated fat. Seeds like pumpkin, sesame, and sunflower are all good choices for healthful fat and flax seeds have high amounts of omega-3s. Nuts and seeds are easy to incorporate into the diet with this nutrient packed granola, in a cool cucumber soup, or in sesame nut brown rice.

Avocados
Avocados are not only a great source of monounsaturated fat, they also contain high amount of vitamin E and are a delicious addition to sandwiches, salads, and, of course, guacamole.

Fish
Salmon, mackerel, tuna, and other cold-water fatty fish are high in omega-3 fats; the American Heart Association recommends eating them at least twice a week and they’re easy to incorporate into the diet. Try salmon with tamari-orange marmalade or butter bean, tuna, and celery salad.

While the low-fat diet craze hasn’t worked -- and has resulted in people substituting fat for artificial ingredients or empty-caloried carbohydrates -- it’s clear that eating more healthful fats, in lieu of trans and saturated, can improve health. And that’s something you can raise your fork to.