WHO'S TRACKING
Inside Dr. Rajani Katta's Case Against Sugar for Your Skin
Walk into any conversation about aging skin and it's all surfaces: which serum, which acid, which laser, which cream to smooth the line that appeared overnight. Dr. Rajani Katta spent years fielding the same question from patients — is there a cream for these deep wrinkles? — and giving the same unsatisfying answer: not really, not once they're deep. A dermatologist and medical-school professor, she went looking for what was actually driving the sag and the creasing beneath the surface, and landed somewhere most beauty advice never goes: the bloodstream. Her conclusion, laid out in her book Glow, reads less like a skincare tip and more like a biohacker's thesis — that one of the biggest threats to your collagen isn't on your bathroom shelf at all. It's the sugar in your diet.
"By the time you see sagging, the damage is already done."
That's the uncomfortable core of it. The glycation she describes is slow, silent, and cumulative — it doesn't announce itself until the collagen is already stiff and the jawline has already softened. Which flips the usual beauty logic on its head: the most powerful anti-aging move might not be something you apply, but something you stop feeding your skin from the inside.The most persistent myth in skincare is that aging skin is a surface problem with a surface fix — that the right topical can undo what's happening structurally underneath. Katta's work reframes aging as something you also eat your way into or out of, and it rests on a specific, well-documented mechanism. Three ideas anchor it:
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Sugar physically stiffens your collagen. When blood sugar spikes, excess glucose latches onto proteins like collagen in a process called glycation, forming compounds aptly abbreviated AGEs. Think of it as collagen slowly caramelizing. Springy, resilient collagen turns stiff and brittle — and brittle collagen is what shows up as deep wrinkles and a slackening jawline. This isn't fringe theory; it's the same chemistry studied in aging research across the body.
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The damage is nearly permanent, so prevention is the whole game. Here's the part that makes it urgent: glycated collagen resists your body's normal repair and turnover. Your skin can't easily swap it out for fresh collagen the way it handles other wear. That's why Katta's emphasis lands so hard on preventing the spikes rather than chasing correction later — once the cross-linking happens, creams can't reverse it.
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Food is a real lever, not a garnish. The flip side is empowering. The same research shows the right foods actively defend skin — antioxidants quench the free radicals that accelerate aging, anti-inflammatory foods calm the background inflammation, and steadier blood sugar simply produces fewer AGEs. Diet isn't a wellness afterthought to a skincare routine; in her framing, it's a structural input to how your skin ages.
The Protocol
Katta distills her approach into three plain keys — the kind of repeatable rules a biohacker would recognize, aimed at the inputs rather than the symptoms.
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Stop sugar spikes. The single most skin-relevant move: blunt the blood-sugar rollercoaster. That means going easy on refined carbs and added sugars, and pairing any sweet or starchy food with protein, fat, or fiber to flatten the spike. Fewer spikes, fewer AGEs, slower collagen damage.
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Eat power. Load the plate with foods naturally dense in protective nutrients — antioxidant-rich vegetables and fruit, anti-inflammatory choices, prebiotic and probiotic foods that support the gut-skin connection. These actively supply what skin needs to repair and defend itself.
- Stop skin sabotage. Cut the quiet accelerants — the refined-carb, high-sugar patterns that drive glycation and inflammation in the background — and keep protecting from the outside with daily sun protection, since UV amplifies the same damage.
The philosophy in one line: your skin ages partly from the inside, on inputs you control, so defend the collagen you have before you go looking for a cream to fake it.
Photo Credit: personal webpage
Inside Her Daily Plate
Because her thesis is inside-out, the "routine" that matters isn't a shelf of products — it's what goes on the plate. These are the food-based inputs her work points to for defending collagen and slowing glycation.
- Protein or fat with every carb: The simplest anti-spike move. Pairing bread, rice, or anything sweet with protein, fat, or fiber flattens the blood-sugar rise that drives AGE formation. It's less about cutting carbs than about never eating them naked.
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Deeply colored produce: Berries, leafy greens, and other richly pigmented vegetables and fruit are dense in the antioxidants that quench the free radicals accelerating skin aging — the "eat power" side of her framework.
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Anti-inflammatory staples: Foods like fatty fish, extra-virgin olive oil, nuts, and herbs and spices calm the background inflammation that compounds collagen breakdown.
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Prebiotic and probiotic foods: Fermented foods and fiber-rich plants support the gut-skin connection her work leans on, feeding the microbiome that influences skin from the inside.
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Water and unsweetened drinks over sugary ones: Swapping soda, juice, and sweetened coffees for water or unsweetened options is one of the biggest single cuts to daily sugar spikes most people can make.
Optimize Your Plate
Concrete swaps and additions to start today:
- Breakfast: Trade the pastry or sugary cereal for eggs with avocado, or plain Greek yogurt with berries and nuts — protein and fat instead of a morning sugar spike.
- Add these collagen-defenders often: blueberries, spinach and kale, broccoli, tomatoes, red bell peppers, and extra-virgin olive oil — all high in the antioxidants that fight AGE formation.
- Fatty fish twice a week: salmon, sardines, or mackerel for anti-inflammatory omega-3s.
- Spice with intent: cinnamon, turmeric, ginger, and garlic — several are shown to blunt glycation specifically.
- Swap the drink first: replace one sugary drink a day with water, sparkling water, or unsweetened green tea (green tea itself is linked to lower AGE activity).
- Trade refined for whole: white bread, white rice, and pastries for whole grains, lentils, beans, and oats that release sugar slowly.
- If you eat something sweet, don't eat it alone: pair it with protein or fat to flatten the spike.
