Nutritionists divide food into three types of macronutrients: carbohydrates, proteins and fats. Each of these macronutrients contains calories, which give your body energy. A calorie is the amount of energy, or heat, it takes to raise the temperature of one gram of water 1 degree Celsius. If you take in more calories than you burn, your body stores that energy as body fat. So, diets recommend that you create a calorie deficit in order to lose weight (the stored body fat). Carbohydrates and proteins each provide four calories per gram, while fat provides nine calories per gram. The number of calories in a fat gram, however, does not reveal the whole story about fats and the role they should play in your diet.
Fats come in different forms: saturated, unsaturated and trans fatty acids (trans fats). Our body makes all the saturated fat it needs, so consuming it is unnecessary, but unavoidable. This fat is largely found in animal proteins and full-fat dairy products. Saturated fat consumption can increase your risk for certain diseases, namely heart disease and possibly cancer. The problem with saturated fat is that it boosts your total cholesterol levels by elevating the LDL levels (the undesirable type of cholesterol). Because of this, nutritionists recommend making saturated fats no more than 10 percent of your total fat-calorie intake.
Unsaturated fats include mono-unsaturated and polyunsaturated fats. Consuming these fats can be good for the body--particularly the type of polyunsaturated fat called omega 3. These fats work on cholesterol, too, but they raise the beneficial HDL levels.
Avocados; oils like canola, olive and peanut; nuts and seeds prove to be great sources of mono-unsaturated fats. Polyunsaturated fats are found in sunflower, corn, soybean and flaxseed oils. Walnuts and fish contain the super nutrient, omega 3, which provides a number of additional health benefits, including improved heart health and brain function.
Trans fats have a horrible reputation, and rightfully so. Companies create these fats by heating liquid vegetable oils in the presence of hydrogen. This makes the fat shelf safe and able to withstand repetitive heating and cooling--which is why fast food restaurants and food manufacturers like to use them. According to a study published in the April 2004 issue of the American Journal of Clinical Nutrition, trans fats create systemic inflammation in women, which indicates the future development of coronary artery disease and diabetes. For every 2 percent of calories consumed from trans fats, the risk for coronary artery disease increases by 23 percent. Trans fats hit your cholesterol levels with a double whammy--they increase LDL and lower HDL. The result is a high total cholesterol level with a poor ratio of good to bad components.
Check your labels for the ingredient partially hydrogenated vegetable oil, even if the food label claims zero grams of trans fats. Food manufacturers don't have to report levels over .5 grams per serving, even if trans fat is included in the product. If you consume multiple servings of a product that contains .5 grams per serving, you could end up with levels deemed unsafe.
Why We Need Some Fat
So fat is higher in calories than other nutrients, and its various forms can be confusing---why not just avoid it altogether? Fat consumption assists the body in important functions. Fat helps waterproof the skin, insulates the body, provides an energy source, builds cell membranes, plays a role in the composition of many hormones and maintains some of the major systems within the body. Fat also allows the absorption of certain vitamins (A,D, E and K).
The USDA recommends that about 30 percent of your total caloric intake be made up of fats. Some diets recommend a slightly lower intake (20 to 25 percent), but regardless, no more than 10 percent of these fat calories should be from saturated sources. Strive to consume zero grams of trans fats. To figure out your fat intake, take the grams of fat you consume a day and multiply by 9 (the number of calories in one gram). This gives you the total number of calories consumed in a day from fat, and you can then figure out what this means in terms of percentage of total calories. You could also use one of the many websites (www.fitday.com, www.sparkpeople.com or others) to record an online food diary. They then show you the exact ratio of your macronutrients--including fat and saturated fat.