It’s time to end the low-fat myth. That’s because the percentage of calories from fat that you eat, whether high or low, isn’t really linked with disease. What really matters is the type of fat you eat.
- Choose foods with healthy fats, limit foods high in saturated fat, and avoid foods with trans fat.
- “Good” fats—monounsaturated and polyunsaturated fats—lower disease risk. Foods high in good fats include vegetable oils (such as olive, canola, sunflower, soy, and corn), nuts, seeds, and fish.
- “Bad” fats—saturated and, especially, trans fats—increase disease risk. Foods high in bad fats include red meat, butter, cheese, and ice cream, as well as processed foods made with trans fat from partially hydrogenated oil.
The key to a healthy diet is to choose foods that have more good fats than bad fats—vegetable oils instead of butter, salmon instead of steak—and that don’t contain any trans fat.
The low-down on low-fat
“Low-fat,” “reduced fat,” or “fat-free” processed foods are not necessarily healthy. One problem with a generic lower-fat diet is that it prompts most people to stop eating fats that are good for the heart along with those that are bad for it. And low-fat diets are often higher in refined carbohydrates and starches from foods like white rice, white bread, potatoes, and sugary drinks.
- When food manufacturers take out fat, they often replace it with carbohydrates from sugar, refined grains, or starch. Our bodies digest these refined carbohydrates and starches very quickly, causing blood sugar and insulin levels to spike and then dip, which in turn leads to hunger, overeating, and weight gain.
- Over time, eating lots of “fast carbs” can raise the risk of heart disease and diabetes as much as—or more than—eating too much saturated fat.
So when you cut back on foods like red meat and butter, replace them with fish, beans, nuts, and healthy oils—not with refined carbohydrates.
Although it is still important to limit the amount of cholesterol you eat, especially if you have diabetes, for most people dietary cholesterol isn’t nearly the villain it’s been portrayed to be. Cholesterol in the bloodstream, specifically the bad LDL cholesterol, is what’s most important. And the biggest influence on blood cholesterol level is the mix of fats and carbohydrates in your diet—not the amount of cholesterol you eat from food.
5 Quick Tips: Choosing Foods with Healthy Fats
1. Use liquid plant oils for cooking and baking. Olive, canola, and other plant-based oils are rich in heart-healthy unsaturated fats. Try dressing up a salad or roasted vegetables with an olive oil-based vinaigrette, such as this recipe for oregano-garlic vinaigrette, or savory almond-based pesto.
2. Ditch the trans fat. In the supermarket, read the label to find foods that are trans free. The label should say “0” (zero) on the line for trans fat; you should also scan the ingredient list to make sure it does not contain partially hydrogenated oils. In restaurants that don’t have nutrition information readily available, steer clear of fried foods, biscuits, and other baked goods, unless you know that the restaurant has eliminated trans fat—many already have.
3. Switch from butter to soft tub margarine. Choose a product that has zero grams of trans fat, and scan the ingredient list to make sure it does not contain partially hydrogenated oils. Even better, use a liquid plant oil whenever possible; refrigerated extra virgin olive oil makes a great spread for toast.
4. Eat at least one good source of omega-3 fats each day. Fatty fish (such as salmon and tuna), walnuts, and canola oil all provide omega-3 fatty acids, essential fats that our bodies cannot make. Omega-3 fats, especially those from fish, are very beneficial for the heart. Read more about omega-3 fatty acids and why they are so important to good health.
5. Cut back on red meat, cheese, milk, and ice cream. Red meat (beef, pork, lamb) and dairy products are high in saturated fat. So eat less red meat (especially red processed meat, such as bacon), and choose fish, chicken, nuts, or beans instead. If you do eat red meat, choose lean cuts and keep the amounts low.
Low-fat and reduced-fat cheeses are often not so low in fat—and are often higher in sodium than regular cheese. So it is best to choose the cheese you like and savor it in small amounts.
Read an in-depth article about fats, cholesterol and health.
Read why Harvard’s new Healthy Eating Plate recommends healthy plant oils—olive, canola, sunflower, safflower, corn, soy, and more—for cooking, on salad, and at the table.
The aim of the Harvard School of Public Health Nutrition Source is to provide timely information on diet and nutrition for clinicians, allied health professionals, and the public. The contents of this Web site are not intended to offer personal medical advice. You should seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this Web site. The information does not mention brand names, nor does it endorse any particular products.