Eating too much sugar hurts your skin in more ways than one: It can cause wrinkles, dark circles, inflammation, sagging, and dehydration. Elastin and collagen molecules, which are necessary for healthy skin, are damaged by diets high in sugar. Consuming too many quick-digesting carbohydrates, such as refined sugar, causes blood sugar to spike. When blood sugar is high, AGEs (advanced glycation end products) are formed, which accelerate the aging process.