If you want better skin, you’ve got to up your skincare game.
Splash out a bit more on a primer. Make sure you’re using a night cream. Exfoliate.
That’s what we’ve all been told. Glowing skin comes from better products. But what if we’re wasting our money?
Skin is built from within. By the time it shows up on the surface of your face, it’s been dead for some time.
The epidermis—the layer of skin you see in the mirror—is made up of cells that are “little more than a dead, scale-like structure … filled with keratin.” 
So, when you apply topical creams, you’re not nourishing living cells. You’re trying to feed dead cells. And those cells aren’t sticking around. You lose around 30,000 scales of skin off your body every minute.
Why waste time, energy and money on dead cells that are going to fall off in a few days or weeks anyway?
Instead, you want to focus your energy on living cells.
The skin cells that lie deep beneath the epidermis, performing a number of vital functions before eventually dying and ending up on the surface of your skin.
This living layer of skin cells is called the dermis.
It’s where all your collagen and elastin fibers are—the stuff that keeps your skin taut, elastic, and wrinkle-free.
You could smear some cream on your skin and hope it penetrates to the dermis, but there’s a much better delivery system for the vital nutrients your living skin cells need:
Your blood carries nutrients from the food you eat to your skin cells, where they form the building block of gorgeous, radiant skin.
So diet—not a beauty cream—is the foundation of great skin.
The food you eat delivers antioxidants, vitamins, minerals, and fats straight to your living skin cells.
When you change your diet, it can take up to a month for those changes to show up on the epidermis, but it will happen. Wait for it. The glow. The smoothness. The skin beauty creams promised to give you.
But no matter how well you take care of your skin—the 8 glasses of water, the flaxseed (favored by beauty editors at Elle), the berries—there is one food mistake that can sabotage it all.
Eat this, and your skin will age faster. Think dark circles under the eyes, breakouts, dullness, and a sallow complexion.
That food mistake is sugar.
Dermatologist Dr. Fredric Brandt was famous for promising you could look 10 years younger if you’d just give up the white stuff.
To be fair, it’s not just sugar. It’s ALL simple carbs, from pastries to crackers. Anything that causes a spike in insulin.
Foods that cause insulin to spike increase oil gland activity and boost acne-causing hormones. Inflammation breaks down collagen and elastin. Sugar byproducts attach to collagen in a process called glycation, causing wrinkles and fine lines.
Dr. Nicholas Perricone of the eponymous skincare line takes a hard line:
[Y]our only source of sugar should be fresh fruits and vegetables.” 
When we think of premature aging, we envision the pack-a-day smoker with her sallow, lined skin. We don’t think of the happy twenty-something standing in line for a venti Frappuccino and cupcake to fuel her studies.
But sugar is not your friend. It’s been conclusively linked to acne, along with dairy.
Dr. Mark Hyman blames our increasingly sweet and milky diet for the fact that 80 to 90% of teens now suffer from acne. 
If the thought of giving up sugar is more terrifying than the thought of wrinkles, here are some ways to mitigate the damage.
Drink green tea. Studies on rats have found that green tea disrupts the glycation process and stimulates collagen synthesis, though more studies are needed. 
Get to sleep before 10pm. The prime sleeping hours for skin repair are between 10pm and midnight, so make sure to give your skin the beauty sleep it needs to repair the damage.
Load up on salmon. Your skin loves those Omega 3s, and salmon is a rich source. In fact, Dr. Perricone’s 3-day skin diet has you eating it twice a day.
But the best thing you can do for your skin is not to make up for the effects of sugar, but rather get rid of it. Shift to a diet rich in low-glycemic foods. The anti-inflammatory diet is a great place to start.
Life is a lot sweeter when you’re getting your pleasure from how you feel, not what you eat.