Fat in the Right Amounts in Your Diet
Getting the right amount of fat in your diet is a delicate balancing act. Too much fat increases your risk of obesity, diabetes, heart disease, and some forms of cancer. Too little fat, and infants don’t thrive, children don’t grow, and people of all ages are unable to absorb and use fat-soluble vitamins that smooth the skin, protect vision, bolster the immune system, and keep reproductive organs functioning.
The National Academies’ Institute of Medicine (IOM) recommends that no more than 20 to 45 percent of daily calories come from fat. On a 2,000-calorie daily diet, that’s 400 to 900 calories from fats a day. The Dietary Guidelines for Americans 2005 lowers that to 20 to 30 percent of total calories. Translation: 400 to 600 of the calories on a 2,000-calorie/day regimen.
Because your body doesn’t need to get saturated fats, cholesterol, or trans fats from food, neither IOM nor the Dietary Guidelines for Americans 2005 have set levels for these nutrients, except to say, Keep them as low as possible, please.
Food contains three kinds of fats: triglycerides, phospholipids, and sterols. Here’s how they differ:
Triglycerides: You use these fats to make adipose tissue and burn for energy.
Phospholipids: Phospholipids are hybrids — part lipid, part phosphate (a molecule made with the mineral phosphorus) — that act as tiny rowboats, ferrying hormones and fat-soluble vitamins A, D, E, and K through your blood and back and forth in the watery fluid that flows across cell membranes.
Sterols (steroid alcohols): These are fat and alcohol compounds with no calories. Vitamin D is a sterol. So is the sex hormone testosterone. And so is cholesterol, the base on which your body builds hormones and vitamins.
American Academy of Pediatrics, the American Heart Association, and the National Heart, Lung, and Blood Institute, recommend restricting fat intake for older children, they stress that infants and toddlers require fatty acids for proper physical growth and mental development, and that’s why Mother Nature made human breast milk so high in fatty acids. Never limit the fat in your baby’s diet without checking first with your pediatrician.
Here’s a simple guide to finding the fat content of foods in your diet. Oils are virtually 100 percent fat. Butter and lard are close behind. After that, the fat level drops, from 70 percent for some nuts down to 2 percent for most bread. The rule to take away from these numbers? A diet high in grains and plants always is lower in fat than a diet high in meat and oils.
As a general rule:
Fruits and vegetables have only traces of fat, primarily unsaturated fatty acids.
Grains have small amounts of fat, up to 3 percent of their total weight.
Dairy products vary. Cream is a high-fat food. Regular milks and cheeses are moderately high in fat. Skim milk and skim milk products are low-fat foods. Most of the fat in any dairy product is saturated fatty acids.
Meat is moderately high in fat, and most of its fats are saturated fatty acids.
Poultry (chicken and turkey), without the skin, is relatively low in fat.
Fish may be high or low in fat, primarily unsaturated fatty acids that remain liquid even when the fish is swimming in cold water. (Saturated fats harden when cooled.)
Vegetable oils, butter, and lard are high-fat foods. Most of the fatty acids in vegetable oils are unsaturated; most of the fatty acids in lard and butter are saturated.
Processed foods, such as cakes, breads, canned or frozen meat, and vegetable dishes, are generally higher in fat than plain grains, meats, fruits, and vegetables.