Does Sugar Cause Skin Problems? What the Evidence Says

By Bella Dorey, BANT Registered Nutritional Therapist

"Cut out sugar and your skin will clear" is one of the most common pieces of dietary advice given to people struggling with their skin. And like most things in nutrition, the truth is more nuanced - but also more useful - than a blanket elimination.

Here's what the evidence actually says about sugar, skin health and what's really worth paying attention to. Does Sugar Cause Skin Problems:

The glycaemic index and skin (Does Sugar Cause Skin Problems)

The connection between dietary sugar and skin conditions - particularly acne - is primarily mediated through blood sugar and insulin. When you eat foods that rapidly raise blood glucose (high glycaemic index foods), your body releases insulin to bring blood sugar back down. This insulin spike triggers a cascade of effects relevant to skin health:

1. Increased androgens: insulin stimulates the production of androgens (male hormones, present in everyone), which increase sebum production. Excess sebum is a key factor in blocked pores and breakout development.

2. IGF-1 elevation: insulin raises levels of insulin-like growth factor 1, which stimulates skin cell proliferation and sebum production, and has been directly implicated in acne pathogenesis in multiple studies.

3. Inflammation: blood sugar spikes drive systemic inflammation, which worsens existing inflammatory skin conditions including eczema, psoriasis and rosacea.

4. Glycation: chronically elevated blood sugar causes a process called glycation, where sugar molecules bind to proteins including collagen and elastin. This cross-linking degrades skin structure, contributing to premature ageing, dullness and loss of elasticity.

The evidence here is reasonably strong. A landmark 2007 randomised controlled trial found that people with acne who followed a low glycaemic load diet for 12 weeks had significantly fewer lesions than those on a high glycaemic diet, alongside reductions in insulin and androgen levels.

But it's not just sugar

Where the "cut out sugar" advice falls short is in its focus on one dietary variable in isolation. Blood sugar management is the key mechanism, not sugar specifically.

This means:

• White bread, rice, pasta and most processed foods raise blood sugar just as rapidly as pure sugar

• Skipping meals and eating erratically destabilises blood sugar even on a low-sugar diet

• Chronic stress raises cortisol, which raises blood sugar independently of what you eat

• Poor sleep significantly impairs insulin sensitivity

So someone who cuts sugar but still eats large portions of refined carbohydrates, skips breakfast and sleeps poorly will see limited improvement. Conversely, someone who focuses on blood sugar stability through regular balanced meals, protein, fat, fibre and complex carbohydrates together, often sees skin improvement without dramatically restricting sugar at all.

The dairy question

Dairy often comes up alongside sugar in skin conversations. The evidence here is more mixed, but some studies suggest a link between milk consumption and acne, potentially due to the natural hormones present in milk and its insulinogenic effect. Full-fat fermented dairy (yoghurt, kefir) appears less problematic than skimmed milk, and the gut-health benefits of fermented dairy may outweigh any negative effects for many people.

It's worth noting that dairy elimination, like sugar elimination, often produces short-term improvement that doesn't persist, suggesting it may be masking rather than resolving an underlying gut permeability issue.

Glycation and skin ageing

For those concerned with skin ageing specifically, the glycation process is worth understanding. Advanced glycation end products (AGEs), formed when blood sugar is chronically elevated, directly damage collagen and elastin, contributing to premature lines, sagging and dullness. AGEs are also found in high quantities in foods cooked at high temperatures (particularly grilled, fried or barbecued foods) independently of sugar content.

Antioxidant-rich foods help combat glycation: colourful vegetables and fruits, green tea, extra virgin olive oil, herbs and spices — particularly cinnamon, turmeric and ginger.

What this means practically

Rather than eliminating sugar entirely, which is rarely sustainable and can create an unhealthy relationship with food, the most evidence-supported approach for skin is:

• Prioritising blood sugar stability through balanced meals (protein + fat + fibre + complex carbs together)

• Reducing refined carbohydrates and ultra-processed foods rather than focusing on sugar alone

• Not skipping meals, particularly breakfast

• Supporting stress management and sleep quality alongside dietary changes

• Including antioxidant-rich foods daily to counter inflammation and glycation

Sugar isn't inherently villainous. Context, quantity and dietary pattern matter far more than any single ingredient.

Bella Dorey is a BANT-registered nutritional therapist specialising in skin and gut health, based in Bury St Edmunds and working with clients across the UK online. If you're struggling with persistent skin symptoms, book a free 20-minute discovery call to explore a root-cause approach.