The energy the body receives from food is measured in calories. The three main sources of calories are carbohydrate, protein and fat. Carbohydrate and protein each provide 4 calories per gram. Fat is the most concentrated source of calories. Fat provides 9 calories per gram.
For a healthy diet, it is generally recommended to limit the daily intake of calories from fat to 30% or less of total calories consumed.
Not All Fats Are Created Equal
Not all fats are the same. But when it comes to weight management and heart healthy eating, all fats should be treated the same way: Stay within your limits!
Whether you take a teaspoon of lard or a teaspoon of vegetable oil, they both have 45 calories and 5 grams of fat. So, don’t kid yourself with that “extra healthy” olive oil you pour on your salad. However, different fats have different characteristics – and also different health benefits. Here is a short list of dietary fats and their characteristics:
Saturated fat comes primarily from animal food products, like meat, poultry and dairy products, but also from tropical oils, like palm oil and coconut oil as well as vegetable shortening and hydrogenated oils. Most saturated fats remain solid at room temperature. That is why butter does not melt, unless exposed to heat.
Most of us use at least some of these products on a daily basis. But heart disease patients must be aware that saturated fat can elevate blood cholesterol and also lower HDL (“good” cholesterol). Ask your doctor or dietitian about saturated fat sources in your diet.
Omega-6 polyunsaturated fat
Omega-6 polyunsaturated fat originates mostly from plant foods. It is typically liquid at room temperature. This fat type is a mixed blessing, since it can lower blood cholesterol – but also HDL (the “good” cholesterol).
Typical sources of omega-6 fats are corn, cottonseed, safflower, sesame seed and soybean oils. Many of these are commonly used in processed food items.
Omega-3 polyunsaturated fat
Omega-3 polyunsaturated fat exists in concentrated form in fatty deep-sea and cold-water fish, like salmon, tuna, mackerel and herring. It is also present in flax seed, canola, soybeans, avocado and olive oil. All of these can help lower blood cholesterol and blood pressure. Heart disease patients can benefit greatly from a diet rich in omega-3 fat.
Monounsaturated fat is another plant-generated fat type. It comes with two desirable effects: One, it lowers blood cholesterol; two, it raises HDL (the “good” cholesterol). Monounsaturated fat is found in canola oil, olive oil, avocado, peanuts and cashews. There are caveats, of course, and heart disease patients should discuss the pros and cons with their doctor or dietitian.
Hydrogenated fat (a.k.a. “transfats”)
Hydrogenation is a chemical process that turns liquid vegetable oils into solids (margarines and shortenings). By adding hydrogen atoms, a chemical bonding process of fatty acids takes place that produces characteristics similar to saturated fats.
Trans fatty acids are commonly found in margarine and many baked goods, like cookies, pies, pastries, crackers, and chips. In recent years, food manufacturers have made progress in reducing or eliminating transfats from many of these popular food items. Heart disease patients are well advised to check nutrition labels for tranfats and choose the brands that don’t contain them.