Don't fear the changes that come with aging. We know more about the benefits of nutrition than ever before. You can put this knowledge to good use as you hit those "milestone birthdays". Instead of dreading the slowdown that comes with the passing of time, fight it! Feed your bones, skin and muscles the nutrients they crave to stay strong, healthy and vibrant.

Which food should be your priority as you hit each decade? Check out this easy-to-use guide--and eat your age.

• Eating Habits

Ah, the metabolically-blessed twenties. Some lucky young women can eat as much as they want without showing much change in body fat or weight. Unfortunately these carefree types may mistake thinness for nutritional health, overindulging in fat calories and underindulging in other nutrients. Over twenty something women go to the opposite extreme-calling a diet soda and a small green salad a meal. The risk: anemia, fatigue, and long term metabolic slowdown, which make it harder to burn calories later on. Or they splurge on junk food at night. They try to make up for it by skipping breakfast. Fight the urge to binge by giving yourself a small bowl of a treat food instead of nibbling straight out of the bag or box. Or stock up on "fun" healthy snacks, such as low-fat corn chips and a low-sodium salsa, which provides complex carbs and vitamin A & C.

• High Fat, Low Fat

If you're chowing down on a high fat diet, youth is a good time to start paying attention to labels. How much fat is too much? For a food item to claim it is "low fat", it must contain 3 grams or less per serving based on at least a 100 calorie serving. An easier rule: Just remember that the calories of fat (1 gram equals nine calories) should be less than 30 percent of the total calories in the food. The type of fat you eat matters, too. Check out food labels for "partially hydrogenated oil" --- a classic man-made dietary villain also known as trans-fatty acid. Research has shown that this type of fat can raise bad serum cholesterol (LDL) and lower good cholesterol (HDL).

• Complex Carbs

Another important goal for your twenties: Reduce simple carbohydrates and increase complex ones. Simple carbohydrates are junk foods such as white bread and sugary baked goods. These filling-but-empty taste treats are made from overly processed flour or other refined nutrients. Instead of grabbing another donut, learn to savor complex carbohydrates like whole grain bread and brown rice. Another tip: Eat potatoes with their skin on. Most pastas are also considered complex carbs, but they're relatively low in fiber and, when top with high calorie sauce, can add up to plate load of fat. A high fiber diet will help you normalize blood sugar and lower blood cholesterol, giving you a head start on disease prevention.

• Calcium Concerns

Up until age 25, your body is still building bone that must last you for the rest of your life. How much calcium do you need and how do you get it? The National Research Council and the Food and Nutrition Board recommends 1,200 mg. of calcium per day, a sum you can get naturally by including yogurt, skim or soy milk, part skim cheese, broccoli, oranges, beans and tofu in your diet daily.

• Calories & Metabolism

By now, you may have established some healthful eating patterns in your daily routine (such as eating dark leafy green salads on most days, lots of fresh fruits, only whole grain breads, and limited fatty foods), plus a reasonable amount of exercise. So why are you gaining weight? One contributing factor is a small but predictable decline in your metabolic rate that starts when you turn 30. The unfortunate result: a gradual reduction in your lean body mass… a.k.a. muscle tissue. Since muscles account for the bulk of our energy needs, less muscle means lower calorie requirements. Working out can help you maintain the optimum level of muscle you want, but you should also eat fewer, though more efficient, nutrient rich calories.

• Bone Mass

Another big change as you turn 30: you stop building bone. What's more, you can start losing bone mass, unless you get the calcium you need to head off osteoporosis. Supplements can help, but it's important to make sure you get plenty of calcium-rich foods such as almonds, parsley, and dried fruit --- especially if your diet is low in dairy products. Calcium-supplemented orange juice is another excellent way to get the nutrients you need.

• Raging Hormones

Women who suffer from PMS may notice it getting more severe as they hit their thirties. Recent evidence hints that the estrogen in soy products may even out the symptoms, reducing the need for chemical remedies like ibuprofen. Soymilk, tofu and soy nuts are all great choices. Pour soymilk on your granola in the morning: chop up some tofu and stir-fry it with some of your favorite crisp veggies.

• Aging Skin

Moisturizer companies know who their market is: women in their thirties who are just starting to experience the result of sun damage, stress, and a genetic predisposition to aging, wrinkling skin. Drinking water can help hydrate, and wearing sunscreen is key. But your diet can also help you preserve the skin on your face and body. Fortify yourself daily with natural antioxidants --- molecules which help fight the "free radicals" that contribute to the aging process --- such as orange juice, melon and green leafy vegetables like spinach and chard. Vitamin A and beta-carotene (in carrots and squash) are also crucial skin-boosters. A big, tasty salad full of romaine, diced carrots, and chopped up oranges can be as much a part of your skin regimen as your cleanser and toner.

• Prevention

As you hit forties, you may become increasingly aware of the health risks in your family history. How can you get the best disease prevention from your diet? If heart disease runs in your family, you may want to pay close attention to the fat content of your food. What's more, you should make sure you get folic acid, which is present in orange juice, leafy green vegetables, dried beans, and wheat germs, especially if you have a high homocysteine level. If you have family history of breast cancer, you'll also want to cut fat from your diet; research is still tentative, but there's evidence that a high fat diet can exacerbate already present risk factors. If someone in your family has had colon cancer, you should pay special attention to the fiber you get. Take in at least 25 grams a day, ideally in high-quality, high nutrient foods like kidney beans. If diabetes is a concern, keep your diet low in concentrated sweets, exercise regularly, and make sure to keep your weight at a healthy level.

• Fatigue Factor

Tired? The increased responsibilities of adulthood can take their toll, whether you're raising up a passel of kids, organizing city council, or both. Sixty percent of your diet should be complex carbs --- the most efficient source of energy in the form of glucose. If you do not get enough high quality carbs (such as brown rice), you burn protein, which is less efficient. High protein diets are all the rage right now, but too much protein can affect your kidneys, in some extreme cases causing headache, bad breath, dizziness, fatigue and nausea (not to mention that most high protein diets are also high in fat). Another important priority for energy is to get your B vitamins. You can get these key nutrients in many grains, fruits and vegetables, including baked potatoes, watermelon, banana, soybeans, and sunflower seeds. Or you can take a supplement to make sure you're getting enough.