Reactive Hypoglycaemia: Why You're Crashing After You Eat
Ever feel shaky, anxious, dizzy, or exhausted an hour or two after eating — especially after something sweet or carby?
You could be dealing with reactive hypoglycaemia— a condition where your blood sugar dips too low after a meal. It’s more common than you think and often flies under the radar, especially in women, people with adrenal or thyroid issues, and those under chronic stress.
Let’s unpack what’s really happening — and how functional medicine can help you stabilise your blood sugar, energy, and mood naturally.
What Is Reactive Hypoglycaemia?
Reactive hypoglycaemia is when your blood sugar crashes after a meal, usually within 2 to 4 hours. This is different from fasting hypoglycaemia (which happens when you go too long without eating).
It’s typically triggered by eating high-carbohydrate meals or snacks, especially ones without enough protein, fat, or fibre to balance them.
How It Works: A Quick Blood Sugar Breakdown
1. You eat a meal high in sugar or refined carbohydrates (like white bread, pasta, juice, biscuits).
2. Your body releases a surge of insulinto shuttle that sugar out of the bloodstream.
3. But sometimes, too much insulin is released (called an “insulin dump”— sending your blood sugar too low, too fast.
4. This triggers a stress response. Your body releases adrenaline and cortisol to rescue you — causing a “crash” with symptoms.
Common Symptoms of a Blood Sugar Crash
Shakiness or trembling
Dizziness or light-headedness
Sweating
Racing heart or palpitations
Anxiety or panic
Intense hunger or food cravings
Fatigue or weakness
Brain fog
Irritability ("hangry")
Nausea
Headaches
If this sounds like you — especially if symptoms improve once you eat again — it’s worth investigating.
What Causes Reactive Hypoglycaemia?
It’s not always a standalone issue — often, it’s a symptom of deeper imbalance, including:
High refined sugar/carbohydrate intake
Poor blood sugar regulation
Adrenal dysfunction (e.g. HPA axis dysregulation)
Insulin resistance or early metabolic syndrome
Thyroid imbalances
Skipping meals or fasting without preparation
PCOS or hormonal imbalances
Alcohol consumption on an empty stomach
Post-bariatric surgery or gut absorption issues
It can also occur in people with healthy weight and no diagnosis — especially if stress is high.
Why Functional Medicine Cares About This
Blood sugar crashes aren’t just uncomfortable — they put your body into a constant state of emergency. Every time your blood sugar dips, you release stress hormones to fix it. Over time, this can:
Exhaust your adrenal glands
Disrupt sleep, energy, and mood
Trigger inflammation and cravings
Fuel hormonal issues and insulin resistance
Left unmanaged, it can increase your long-term risk of type 2 diabetes, cardiovascular disease, and metabolic dysfunction — even if your weight is normal.
Functional Medicine Strategies to Support Blood Sugar Balance
Here’s how we calm the rollercoaster and build a more stable foundation:
1. Prioritise Protein, Fat, and Fibre at Every Meal
The combination of these three slows glucose release and reduces insulin spikes.
Try:
Eggs with avocado and spinach
Protein smoothie with chia and nut butter
Leftover roast veg and chicken salad
Tinned fish with hummus and crackers
Avoid eating "naked" carbs (e.g. fruit, toast, crackers) on their own — always pair with a protein or fat.
2. Reduce Refined Carbs and Sugars - especially on their own
Cut back on:
White breads, pastries, cereal
juice, soft drinks, and sweetened yoghurts
Ultra-processed snack foods
Opt for low-GI whole carb foods:
Quinoa, buckwheat, oats, brown rice
Lentils, beans, sweet potato
Berries, apples, and citrus
3. Eat Regularly (at First)
Until your body is better regulated, aim to eat every 3–4 hours — with balanced macronutrients.
Avoid long fasts or skipping meals, especially breakfast.
As your metabolism improves, you may become more resilient to longer gaps between meals.
4. Support Stress and Cortisol Balance
Cortisol is critical in blood sugar regulation. Chronic stress can worsen crashes.
Try:
Deep breathing, yoga, or walking in nature
Adaptogenic herbs (under practitioner supervision)
Magnesium and B vitamins for nervous system support
Prioritising sleep and downtime
5. Consider Functional Testing
Testing can help identify root causes such as:
Insulin resistance or fasting insulin levels
Cortisol rhythm (DUTCH or salivary testing)
Thyroid dysfunction
Nutrient deficiencies (e.g. magnesium, chromium, B6)
Gut issues (SIBO, malabsorption)
The right data = targeted support.
Helpful Quick Tips
Don’t have coffee on an empty stomach — it spikes cortisol and blood sugar.
Always carry a protein-rich snack (like nuts, boiled eggs, or protein bars).
If you feel a crash coming on, try a spoon of nut butter or a few olives — it can help stabilise you quickly. Add in some healthy complex carbs for balance ( Peanut butter on apple slices is delcious)
Be cautious with alcohol — it can crash your blood sugar fast, especially if mixed with soft drinks
Final Thoughts
If you’ve been told “everything looks normal” but you still feel like your energy, mood, or brain are all over the place — reactive hypoglycaemia may be the missing piece.
With the right food, rhythms, and functional support, you can calm the crashes, feel more in control, and finally trust your body again.
Your body isn’t broken — it’s just craving stability. And with a few changes, that’s 100% possible.
~ Disclaimer: This blog post is for informational purposes only and should not be considered medical advice. Always consult with a healthcare professional for personalised guidance on diet and health ~
