Parul Kharod
We have talked about calories, carbohydrates and protein. Now let’s tackle the other most important macronutrient – fat.
The word fat can mean different things to different people. For cooks, it is an indispensable ingredient. For people battling overweight and obesity, it is an ugly adjective and a thing to be shunned. For nutritionists, it is a whole another ballgame. Every day there is new research contradicting a previous study about the health benefits or dangers of fat.
Fat in itself is not bad. In fact, it is extremely important for the normal functioning of our bodies. Then why and how did fat get such a bad rap? The problem is that the fat has not changed over the years, we have. Our lifestyles have changed – bringing on health concerns not previously known. A sedentary lifestyle, change in food habits, less home cooked meals, and increased stress levels all have contributed to the obesity and diabetes epidemic, and who gets all the blame? Fat, of course!
Here we will try to correct some of the myths associated with fats, and hopefully create awareness about this misunderstood component of food.
Functions of Fat
Fats are organic compounds that are made up of carbon, hydrogen, and oxygen. The primary function of fat is storage for energy. Fat is a macronutrient. There are three macronutrients: protein, fats and carbohydrates. Macronutrients provide calories or energy. Fat has 9 calories per gram, more than twice the number of calories in carbs and protein, which have 4 calories per gram. All fats have the same number of calories regardless of the type of fat.
Fat is also needed for growth and development. Certain specific dietary fats have other essential functions.
• A source of energy: Fat is used to provide energy for most functions in our body to survive.
• As energy reserves: The extra calories that we consume, but do not need to use immediately, are stored for future use in special fat cells (adipose tissue)
• Essential fatty acids: Dietary fats essential for growth development and cell functions. Essential fatty acids contribute to brain development; help with blood clotting and help control inflammation.
• Proper functioning of nerves and brain: Fats are part of myelin, a fatty material which wraps around our nerve cells so that they can send electrical messages. Our brains contain large amounts of essential fats.
• Maintaining healthy skin and other tissues: All our body cells need to contain some fats as essential parts of cell membranes, controlling what goes in and out of our cells
• Transporting fat: Soluble vitamins A, D, E and K through the bloodstream to where they are needed
• Production of hormones: Needed to regulate many bodily processes
• Insulation: Fat surrounds vital organs and helps act as a protective cushion. A thin layer of fat also insulates the skin and helps maintain proper body temperature.
Types of Fats
Fats belong to a group of substances called lipids, and come in liquid or solid form. All fats are a mix of saturated, monounsaturated, and polyunsaturated fatty acids.
The Good: Unsaturated Fats
Unsaturated fats are considered healthy fats because they play many beneficial roles. They can improve blood cholesterol levels and help lower inflammation. Unsaturated fats are found in plant foods such as nuts, seeds, avocados and olives. The oils are liquid at room temperature.
There are two types of unsaturated fats, monounsaturated and polyunsaturated fats. Monounsaturated fats are found in high concentrations in olive, peanut, and canola oils, avocados, nuts such as almonds, hazelnuts, and pecans, seeds such as pumpkin and sesame seeds. Polyunsaturated fats are found in high concentrations in sunflower, corn, soybean, and flaxseed oils, walnuts, and flax seeds. Omega-3 fats are an important type of polyunsaturated fat. The body can’t make these, so they must come from food. Omega-6 fatty acids are found mostly in liquid vegetable oils like soybean oil, corn oil, and safflower oil. A healthy diet should contain a balance of omega 3 and omega 6 fats. Some studies have suggested that too many omega 6 fats in the diet may increase inflammation.
That is why we should limit use of oils and get small amounts of healthy fats from nuts and seeds. There is a misconception that foods fried in olive oil are healthier than foods fried in other oils. For long term health, it is better to avoid all fried foods – it really does not matter which oil the food is fried in. Limiting the total amount of oil is important.
The Bad: Saturated Fats
Saturated fats are mainly found in animal foods such as meat, eggs, and dairy. Saturated fat is solid at room temperature such as ghee, butter, lard, and animal fats. A few plant foods are also high in saturated fats, such as coconut, coconut oil, palm oil, and palm kernel oil. Saturated fats raise the LDL cholesterol. The Dietary Guidelines for Americans recommends getting less than 10 percent of calories each day from saturated fat. The American Heart Association goes even further, recommending limiting saturated fat to no more than 7 percent of calories.
The Ugly: Trans Fats
Trans fats are called the ugly fats and are worse for cholesterol levels than saturated fats because they raise bad LDL and lower good HDL cholesterol. They increase inflammation which has been linked to heart disease, stroke, diabetes, and other chronic conditions. Trans fats also contribute to insulin resistance and increase risk of diabetes. Trans fats have harmful health effects even in small amounts – for each additional 2 percent of calories from trans fat consumed daily, the risk of coronary heart disease increases by 23 percent.
Trans fats are found in ready to eat packaged foods, baked goods and fast food. Trans fats increase shelf life so all packaged and processed foods have trans fats. To identify trans fats, look for the words “hydrogenated fat” on the ingredient list. A 2006 labeling law has required food companies to list trans fats on food labels.
Triglycerides
Triglycerides are the end product of digesting and breaking down fats in food. High triglycerides are linked to insulin resistance, increased risk of diabetes and heart disease. Higher triglycerides are usually the result of too many simple sugars and starches in the diet.
We will continue the fats conversation and how to lower cholesterol and triglycerides in next month’s article.
— Parul Kharod, MS, RD, LDN is a registered dietitian and licensed nutritionist and works as a Clinical Dietitian with Outpatient Nutrition Services at WakeMed Hospital in Cary and Raleigh. She can be reached at [email protected]
Posted: Monday, July 3, 2017
