Diet and exercise mistakes that age you

Eating too much sugar certainly isn't wise for your waistline, but did you know that overindulging in dessert can add years to your face? And even if you do strenuous cardio workouts each week, you'll be missing out on potential anti-aging body benefits if your schedule doesn't include yoga, weight training and rest.

Find out if you're making one of these eight common diet and exercise mistakes, and get smart prevention strategies that can keep you slim and youthful for years to come.

The breakdown of sugars, called glycation, damages the collagen that keeps skin smooth and firm. To prevent this natural process from careening out of control, dermatologist Dr. Naila Malik sticks to low-glycemic carbs like whole grains. They're naturally low in sugar, and the body processes them slowly to limit the loss of collagen. If you want to sweeten up your tea or oatmeal without making your skin look older, try all-natural stevia; doctors say it's an easily digested herbal sweetener that doesn't trigger glycation.

Taking your work angst out on the bike or treadmill might make you feel better for a little while, but incorporating yoga into your fitness routine regularly may help you look younger and prevent breakouts while whittling away stress.

Dermatologists say yoga moves such as child's pose, downward-facing dog and sun salutations improve circulation -- the boost of oxygen is what gives skin that lovely yoga glow. And new research finds regular yoga practice may reduce the inflammation and stress that speed skin aging.

Need another reason to "om" away your stress? High levels of tension can spike hormone production that can aggravate or cause conditions like psoriasis.

Research suggests that green and black tea contain protective compounds -- like EGCG and theaflavins -- that help prevent skin cancers and the breakdown of collagen, the cause of wrinkles.

"Hormones in traditionally produced dairy, poultry and meat may contribute to acne," says Dr. Katie Rodan, a dermatologist in the San Francisco Bay Area. She says that her patients who eat those less frequently -- or at least choose grain-fed beef and poultry and organic dairy -- often notice their skin looks better.

When your exercise routine is so intense that you're tired all the time but can't sleep at night, you're setting yourself up for overuse injuries -- not to mention dark circles and bags under your eyes. These symptoms could be a sign of overexhaustion, says author and personal trainer Ryan Halvorson. Other clues that you're working out too much: extreme muscle soreness that persists for several days, unintended weight loss, heightened resting heart rate, interruptions in your menstrual cycle or decreased appetite. Experts recommend planning your rest as well as you plan exercise.

When your diet isn't balanced, your skin, hair and nails will suffer. Cutting calories can deprive your body of certain nutrients that promote healthy cell division, cell regeneration and overall skin tone and texture, says Dr. David Bank, director of the Center for Dermatology, Cosmetic and Laser Surgery in Mount Kisco, N.Y. The skin requires fatty acids, which the body can't produce on its own, to maintain hydration. A diet too low in fat could cause dry skin, hair loss and brittle nails, he says.

Other key youth-boosting nutrients include vitamins A, C and E. Vitamin A deficiencies can cause acne, dry hair, dry skin and broken fingernails; get your daily fix by eating five baby carrots each day. A lack of vitamin C can affect collagen synthesis (the "glue" that binds our ligaments, bones, blood vessels and skin), impair wound healing and make you more likely to bruise. Incorporate vitamin C-rich foods in the form of citrus fruits, Brussels sprouts, peppers and leafy greens. Low levels of vitamin E can result in easy bruising and cause chronic skin conditions such as eczema and psoriasis to flare up. Get more vitamin E in your diet by eating almonds, hazelnuts, peanuts, spinach and fortified cereals.