Added sugar

Why it matters

Added sugar undermines hormones through one central mechanism: insulin. Every hit of sugar spikes insulin, and chronically high insulin drags testosterone down — one study found that a single glucose load temporarily lowered men's testosterone by around 25%. Sustained over months and years, high sugar intake drives insulin resistance and weight gain, and excess body fat raises the conversion of testosterone to estrogen. For women, the same insulin dysregulation sits at the very heart of conditions like PCOS. It's important to be precise, though: this is about added sugar and refined carbohydrate, not the natural sugar in whole fruit, which comes wrapped in fibre.

What's inside

Added sugar (sucrose and fructose) is the definition of empty calories — energy with no vitamins, minerals or fibre to slow its absorption. That rapid absorption is the problem: it produces sharp insulin spikes, and over time insulin resistance. Fructose in particular, in large amounts, burdens the liver and promotes fat storage. None of this carries any compensating nutritional benefit.

For men

For men, the testosterone story is direct: acute sugar loads lower testosterone temporarily, and chronic high intake drives the insulin resistance and belly fat that lower it long-term — fat tissue also converts testosterone to estrogen. Cutting added sugar is one of the most effective dietary moves for protecting testosterone, steadying energy and improving body composition.

For women

For women, insulin balance is foundational to hormonal health, and added sugar is its biggest dietary disruptor. High sugar intake worsens PCOS (an insulin-driven condition), aggravates mood and energy swings, and fuels the weight gain that further unbalances hormones. Reducing added sugar is often the single most impactful dietary change for women managing PCOS or cycle irregularity.

How to eat it

Target added sugar specifically: sugary drinks, sweets, desserts, and the hidden sugar in sauces, cereals and "healthy" snacks (read labels — it hides under many names). Keep whole fruit, which is fine. Replace sweet snacks with protein, nuts or dark chocolate, and you'll flatten the energy crashes and cravings that high sugar creates, usually within days.

Worth knowing

The distinction matters: this isn't anti-carbohydrate or anti-fruit, it's anti-added-sugar and refined starch. The cravings ease surprisingly quickly once you cut back, as your blood sugar stabilises. For both protecting testosterone and managing women's hormonal conditions, reducing added sugar is among the highest-impact changes available.

Bottom line

Added sugar suppresses testosterone through insulin spikes and fat gain, and sits at the centre of women's insulin-driven conditions like PCOS — making it one of the most worthwhile things to cut, while keeping whole fruit.