Dr. Michael F. Roizen, chairman of the Wellness Institute at Cleveland Clinic in Cleveland, board-certified in internal medicine and anesthesiology, says too high a blood-sugar level damages protein components of skin -- collagen and elastin, the "scaffolding" that holds up skin -- which leads to signs of aging such as wrinkles, dullness and sagging.
This dysfunction of skin-cell proteins makes skin even more vulnerable to outside aggressors such as damage from ultra-violet rays.
High blood sugar is also responsible for exacerbating other inflammation-resulting conditions such as chronic skin problems such as rosacea and acne.
Roizen says a morning cup of coffee or a box of doughnuts are obvious sources of sugar, but simple sugars also lurk in many unexpected foods.
As a general rule of thumb, to stay healthy and avoid unnecessary weight gain, people should not eat more than 4 grams of added sugars per hour, Roizen says.
But even "healthy" foods can exceed 4 grams by a lot, he says.
Roizen wrote in the U.S. News & World Report some unexpected sources of simple sugars include:
-- Chocolate milk can contain 30 grams of sugar per cup.
-- Energy bars can contain 30 to 50 grams of sugar.
-- Sports drinks can contain 55 grams of sugar.
-- Non-fat fruit-flavored yogurt can contain 47 grams of sugar.
-- Granola can contain 14 grams of added sugar in half a cup.
-- Bottled fat-free salad dressings can contain 2 to 6 grams of sugar per 2-tablespoon serving.
-- Ketchup and BBQ sauce can contain 6 grams of sugar per ounce, or about four squeeze-packets' worth.
-- Fruit juice can contain 22 to 36 grams of sugar in one cup.