Monounsaturated fats, like all dietary fats, provide the body with an efficient energy source. These fats are in liquid form at room temperature but can become more solid when refrigerated. The two types of monounsaturated fats found in the diet are oleic acid and palmitoleic acid.
Oleic acid is the main source of monounsaturated fats found in foods. Key food sources for these fats include
• Vegetable oils (olive oil, canola oil, peanut oil, mid-oleic sunflower oil, and other mid- and high-oleic vegetable oils)
• Nuts and seeds (including almonds, cashews, pistachios, and peanuts)
Palmitoleic acid is found in macadamia nuts, some fish oils, and beef fat.
Many foods that are rich in monounsaturated fats are also good or excellent sources of other key nutrients (for example, vegetable oils are rich sources of vitamin E, and nuts and seeds provide plant protein, fiber, and some vitamins and minerals).
Studies have shown that replacing saturated fats with monounsaturated and polyunsaturated fats (although keeping calories consistent) can lower bad low-density lipoprotein (LDL) cholesterol levels. This can protect cholesterol from accumulating in the linings of arteries that lead to the heart or the brain and can cause a heart attack or stroke, respectively.
A recent review of several studies found that those who consumed a high-ft diet with 22-23 percent energy from monounsaturated fats lowered their total blood cholesterol, very low-density lipoprotein cholesterol, and blood triglycerides more than those who consumed a low-fat, high-carbohydrate diet.
Too much of any fat – even healthful monounsaturated fat – can lead to excess calorie intake and contribute to the development of being overweight or obesity. That can increase the risk of diet-related diseases including heart disease, high blood pressure, and type 2 diabetes.