How Blood Sugar Affects Your Hormones (And Why You Should Care)

You might think blood sugar is only relevant if you're diabetic or trying to lose weight. But if you've ever crashed hard at 3pm, felt rage-hungry between meetings, or noticed your PMS symptoms are worse after a few days of chaotic eating, your blood sugar may be asking for your attention.

Blood sugar balance affects far more than just energy. When it's unstable, your entire hormone system feels it. Your cycle becomes irregular. Your mood swings wildly. Your skin breaks out. You crave sugar constantly, especially in the week before your period. You may feel exhausted despite sleeping enough.

These aren't separate issues. They're all connected to how your body manages glucose—and whether your hormones can function properly as a result.

What Is Blood Sugar (And Why Does It Matters)?

Blood sugar, or glucose, is your body's preferred source of quick energy. When you eat carbohydrates—whether that's fruit, bread, pasta, or chocolate—your body breaks them down into glucose. Your blood sugar rises. In response, your pancreas releases insulin, a hormone that helps move that glucose into your cells to be used immediately or stored for later.

When this system works well, you feel energised, focused, and stable. You can go several hours between meals without feeling shaky or desperate for food. Your energy doesn't spike and crash throughout the day.

But modern life makes stable blood sugar difficult. Irregular meals, processed foods, chronic stress, poor sleep, and relying on caffeine to get through the day all disrupt this delicate balance. When your blood sugar spikes too high or drops too low repeatedly, your entire metabolic and hormonal system suffers.

You might notice:

• Energy crashes in the afternoon that have you reaching for coffee or sugar

• Intense sugar cravings, especially in the week before your period

• Brain fog or difficulty concentrating after meals

• Feeling shaky, irritable, or anxious when you're hungry

• Needing to eat every 2-3 hours or you feel terrible

• Waking up in the middle of the night, wide awake and wired

These aren't signs you need more willpower. They're your body telling you something is off with how it's managing glucose.

Blood sugar regulation is foundational. Every functional medicine practitioner, nutritional therapist, and holistic health professional starts here because you can't address hormones, energy, or chronic health issues effectively if blood sugar is chaotic.

How Blood Sugar Disrupts Your Hormones

Insulin and Sex Hormones

When you eat a lot of refined carbohydrates or sugar, your blood sugar spikes. Your body responds by releasing more insulin to bring it back down. Over time, if this happens frequently, your cells can become less responsive to insulin—a condition called insulin resistance.

High insulin levels suppress a protein called sex hormone binding globulin (SHBG). SHBG's job is to bind to oestrogen and testosterone, keeping them inactive until your body needs them. When SHBG is low, you end up with more free-floating, active hormones in your bloodstream.

This can show up as:

• Worsening PMS symptoms

• Irregular or heavy periods

• Hormonal acne, particularly around your jawline

• Mood swings and irritability

• Difficulty losing weight, especially around your midsection

For women with PCOS, this connection is particularly important. PCOS is fundamentally a condition of insulin resistance. Managing blood sugar is one of the most effective ways to improve symptoms like irregular cycles, acne, and excess hair growth.

Blood Sugar Across Your Menstrual Cycle

Your insulin sensitivity—how well your body responds to insulin—changes throughout your cycle. In the first half (follicular phase), you're generally more insulin-sensitive. Your body handles carbohydrates efficiently. You have stable energy and fewer cravings.

In the second half (luteal phase), particularly the week before your period, you become less insulin-sensitive. This means blood sugar is more likely to spike and crash. You might notice you're hungrier, craving sugar and carbs, feeling more tired, and struggling with mood swings or irritability.

You’re craving for chocolate or cake during this time isn't a lack of willpower. Your physiology is different during this phase. Understanding this can help you adjust how you eat—eating more regularly, prioritising protein and fat, and being gentler with yourself when cravings hit.

Blood Sugar and Stress Hormones

When your blood sugar drops too low—say, because you skipped breakfast or had just coffee and a pastry—your body interprets this as a threat. To bring your glucose back up, it releases stress hormones like cortisol and adrenaline.

This is why you feel shaky, anxious, irritable, or wired when you're hungry. Your body is literally in fight-or-flight mode.

If this happens frequently—skipping meals, eating irregularly, relying on caffeine and quick carbs—your stress response stays activated. Over time, this can dysregulate your nervous system, worsen anxiety, disrupt sleep, and contribute to burnout.

Blood Sugar and Thyroid Function

Your thyroid controls metabolism and energy production. Thyroid hormones need stable blood sugar to function properly. When glucose swings wildly throughout the day, it can interfere with the conversion of inactive thyroid hormone (T4) into its active form (T3).

This can contribute to symptoms like persistent fatigue, weight gain, brain fog, and feeling cold all the time—even if your thyroid blood tests come back "normal."

Blood Sugar in Perimenopause and Menopause

As oestrogen declines during perimenopause and menopause, insulin sensitivity often decreases as well. This makes it easier to gain weight (often around your midsection) and harder to keep blood sugar stable.

Many women notice that their tolerance for sugar and carbs changes during this time. Foods that used to be fine suddenly cause energy crashes or weight gain. Blood sugar swings become more pronounced, especially if stress is high or sleep is poor.

This phase requires recalibrating how you eat. What worked in your 20’s or 30s might not work in your 40s and 50s. That's not failure—that's your body changing, and your approach needing to change with it.

What Can Help To Stabilise Blood Sugar

Balancing blood sugar doesn't require perfection or cutting out entire food groups. Small, consistent changes make a significant difference.

1. Prioritise Protein at Every Meal

Protein slows the absorption of glucose into your bloodstream, preventing spikes and crashes. It also supports stable energy and reduces cravings.

Aim for around 30g of protein at breakfast and 20-30g at lunch and dinner. This might look like eggs and avocado on sourdough, Greek yogurt with nuts and berries, lentil soup with quinoa, or grilled chicken with vegetables and rice.

Your individual protein needs depend on your age, activity level, and health status. These are guidelines, not rules. Some women need more, some need less.

2. Eat Carbohydrates Earlier in the Day

Your body handles carbohydrates most efficiently in the morning and early afternoon. Front-loading complex carbs—oats, sourdough toast, sweet potato—earlier in the day can help keep blood sugar stable.

This doesn't mean eliminating carbs at dinner. You still need them for sleep and recovery. Just consider shifting the bulk of your intake to earlier meals.

3. Balance Your Plate

At lunch and dinner, include protein, fiber (leafy greens, lentils, beans), healthy fats (olive oil, nuts, avocado, tahini), and slow-release carbohydrates (sweet potato, brown rice, quinoa).

This combination keeps glucose steady, reduces cravings, and helps you feel satisfied for longer.

4. Eat Regularly

Going too long without food causes blood sugar to drop, triggering the release of stress hormones. This sets you up for a crash—or reaching for quick sugar or caffeine to compensate.

Eating every 3-5 hours works well for most women. If you're experiencing burnout or adrenal fatigue, you might need to eat every 2-3 hours initially to stabilise energy before longer gaps feel manageable.

5. Move After Meals

A 15-20 minute walk after eating can significantly improve your blood sugar response. You don't need intense exercise—just consistent movement shortly after eating.

This is particularly helpful after larger or carb-heavy meals.

Where to Start

If you're reading this and recognising yourself in these patterns—the afternoon crashes, the irritability when hungry, the sugar cravings before your period—it’s a sign that your blood sugar regulation needs support.

Start with one habit. Maybe that's adding protein to breakfast. Maybe it's eating every 4 hours instead of skipping lunch. Maybe it's a short walk after dinner.

Notice how your body responds. Do you have more stable energy? Fewer cravings? Better mood? Less PMS? That feedback tells you whether you're moving in the right direction.

Your hormones depend on this foundation. Give them the stability they need to do their job properly.

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