Since sources of fat are more calorie-dense, it is important to understand what a serving of a fat is equivalent to. For example, one teaspoon of butter, margarine or mayonnaise is one fat serving. For times when you may not have a measuring spoon available, a visual equivalent of one teaspoon is the tip of your thumb. See below for examples of serving sizes for added fats.
Polyunsaturated fats can also be healthy. The two main types are omega-3 and omega-6 fatty acids, essential fats our bodies need for brain function and cell growth. Omega-3s are beneficial for every aspect of heart health, and are mostly found in fish and algae, nuts, and seeds. “Other polyunsaturated fats, [omega-6s], can be found in certain plant-based oils,” Hunnes adds. “They’re not particularly harmful, but not necessarily beneficial the way omega-3s and monounsaturated fats are.” Omega-6s work alongside omega-3s to lower LDL cholesterol, but research suggests that eating more omega-6 than -3 may contribute to inflammation and weight gain, so the key is to make sure your omega-3 intake is always higher.
Saturated fat. This is a type of fat that comes mainly from animal sources of food, such as red meat, poultry and full-fat dairy products. Saturated fat raises total blood cholesterol levels and low-density lipoprotein (LDL) cholesterol levels, which can increase your risk of cardiovascular disease. Saturated fat may also increase your risk of type 2 diabetes.
Other studies have confirmed the health benefits of following a low-carb diet rather than a low-fat diet. In one study, women lost more weight following a low-carbohydrate diet than a low-fat diet (5). In addition to weight loss, studies also show that low-carb, high-fat diets reduce inflammation, regulate blood sugar levels, and reduce triglycerides while raising HDL cholesterol levels (6,7).