Should I try to eat a low-fat diet when I’m pregnant?
It’s easy to get confused and think that eating healthy means avoiding fat altogether. People who watch their weight avoid fat because it packs a high-calorie punch: Fat provides 9 calories per gram, more than twice the number in carbohydrates or protein. But the truth is, some kinds of fat are good for us. Our bodies need some fats in order to absorb and use vitamins such as A, D, E, and K. Fats also aid the body in processing protein and carbohydrates and turning them into energy. And the fat you eat will help your baby develop soft, healthy skin and good vision.
If you eat more fat than you need right away, your body stores it for future use. This fat tissue can be converted back into energy when you need extra calories. While you don’t want to build up these fat stores too much, your body needs some fat tissue available for times of need — for example, when you begin to make breast milk for your newborn.
How much fat is it okay to eat?
Americans generally eat more fat than they need. As a rule of thumb, experts recommend between 20 and 35 percent of the calories you eat in a day come from fat. Of these, less than seven percent should come from saturated fat, according to the American Heart Association. And avoid trans fats. These are found in foods like stick margarine, fast food, and many commercial baked goods like donuts, crackers, and cookies.
To avoid eating more fat than you want to, watch out for hidden fats in your diet. Prepare meat and fish by grilling, baking, or poaching rather than frying. And steam or broil vegetables rather than sauting them in butter. Avoid fat-laden sauces such as hollandaise or cream sauce.
Which kinds of fat are considered healthiest?
The healthiest fats are unsaturated fats, which come mostly from vegetables, nuts, and other plant sources. There are two kinds of unsaturated fats: monounsaturated and polyunsaturated.
Monounsaturated fats These include the oils considered the most heart-healthy, including olive oil and canola oil. Peanut oil and other nut oils are also monounsaturated. One way to distinguish monounsaturated oils is that they usually don’t stay liquid in the refrigerator. Avocados and most nuts also have high amounts of monounsaturated fat.
Polyunsaturated fats. Other vegetable oils such as safflower oil, corn oil, sunflower oil, and generic “vegetable oil” are polyunsaturated. You can tell because they stay liquid even when refrigerated. These fats are considered less healthy than monosaturated fats, with the exception of omega-3 fatty acids.
Omega-3 fatty acids are polyunsaturated fats that come primarily from fish and some nuts and seeds and are important for brain function. Fatty, cold-water fish such as salmon, mackerel, and herring are the best sources of omega-3s.
But be wary of eating too much of certain types of fish when you’re pregnant. Some fish contain high levels of mercury that can threaten your baby’s healthy development. The FDA issued an advisory recommending that pregnant women avoid eating four types of fish that are particularly high in mercury: swordfish, shark, mackerel, and tilefish. However, pregnant or nursing women can safely eat up to 12 ounces per week of seafood that is low in mercury, such as canned light tuna (not albacore). Flaxseeds, flax oil, and walnuts also contain omega-3 fatty acids.
Which fats are bad for me?
Saturated fats.Because saturated fats come primarily from animals, they can increase your total cholesterol and LDL (“bad”) cholesterol, which is not healthy for your heart. Butter, lard, palm oil, and coconut oil are examples of saturated fats.
Trans fats. These man-made fats are the worst for your health, so avoid them as much as you possibly can. Among other things, they are known to reduce levels of HDL (“good cholesterol”)and boost levels of “bad” LDL cholesterol. Trans fats are created by adding hydrogen to vegetable oil through a process called hydrogenation. This makes the fat more solid and less likely to turn rancid. Manufacturers are now required to list trans fats separately on nutrition labels. You can also tell if a product contains trans fats by looking for the words “partially hydrogenated’ in the list of ingredients.
Trans fat is a common ingredient in store-bought baked goods such as crackers and cookies, fried foods like french fries, and some shortenings and margarines. Since January 1 of 2006, food manufacturers have had to list trans fat content on nutrition labels. Some food manufacturers are scrambling now to remove the trans fat from their products and are announcing “no trans fat” on their labels.
References
Board of Health votes to phase out artificial trans fats from New York City’s restaurants, press release, December 5, 2006, The New York City Department of Health and Mental Hygiene. http://www.nyc.gov/html/doh/html/pr2006/pr114-06.shtml
Cleveland Clinic. Reducing Fat Intake. http://www.clevelandclinic.org/health/
The Mayo Clinic. Dietary fats: Know which types to choose. January 2009. http://www.mayoclinic.com/health/fat/NU00262
Elmhurst College. Overview of Lipid Function. http://www.elmhurst.edu
Nutrition for Optimal Health Association. Fish, Oils, and Vision. http://www.nutrition4health.org/NOHAnews/NNF87FishOilsVision.htm
American Congress of Obstetrics and Gynecology (ACOG) Planning Your Pregnancy and Birth, Third Edition.
American Heart Association. American Heart Association weighs in on fat substitutes. http://www.americanheart.org/
U.S. Food and Drug Administration. Revealing Trans Fats. http://www.fda.gov/fdac/features/2003/503_fats.html
U.S. Food and Drug Administration. An Important Message for Pregnant Women and Women of Childbearing Age Who May Become Pregnant About the Risks of Mercury in Fish. http://www.cfsan.fda.gov/~dms/admehg.html
Journal of Nutrition, Health and Aging. Dietary omega-3 fatty acids and psychiatry: mood, behaviour, stress, depression, dementia and aging. Bourre JM. 2005;9(1):31-38.
American Heart Association. Know Your Fats. http://www.americanheart.org/presenter.jhtml?identifier=532
US Department of Health and Human Services, US Department of Agriculture. Dietary Guidelines for Americans 2005. http://www.health.gov/dietaryguidelines/dga2005/document/default.htm
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