Real-World Nutrition During Perimenopause: What Actually Helps Mood Swings and Brain Fog

If you’re in your 40s and deep in the perimenopause trenches, you already know how unpredictable your mind and mood can feel. One day you’re fairly steady, doing your thing. The next? You’re tearful, irritable, overwhelmed… or standing in the kitchen wondering why you opened the fridge and what you were even looking for.

Mood swings. Brain fog. Sudden drops in motivation. Emotional sensitivity. Forgetfulness. PMS that feels dialled up to maximum. And a mental load that already feels heavy before the hormones even get involved.

If this sounds like you, let me say this gently and clearly - You’re not losing your mind. You’re navigating a hormonal transition that genuinely affects your brain. And the right nourishment can help, not in a diet-culture, restrictive way, but in a deeply supportive, real-world way and support your nutrition during perimenopause.

Let’s walk through what’s actually happening in your body, and what truly helps in daily life.

Why Perimenopause Impacts Your Mood, Clarity, and Emotional Stability

Perimenopause isn’t a slow slide toward menopause. It’s more like a hormonal rollercoaster with twists, dips, and sharp turns you don’t see coming. And because your brain is packed with hormone receptors, every hormonal fluctuation affects how you think, feel, remember, and cope.

Oestrogen goes up and down… and takes your mood with it

Oestrogen helps regulate:

• serotonin (your mood stabiliser)

• dopamine (your motivation and focus)

• acetylcholine (your memory and attention)

This is why sudden drops can cause:

• irritability

• emotional outbursts

• low mood

• forgetfulness

• disorganisation

• that “I can’t think straight” fog

Progesterone gently declines

Progesterone is your calming hormone, the inbuilt soothing system. As it drops, many women feel:

• more anxious

• less resilient

• easily overwhelmed

• wired but tired

Testosterone slowly reduces (and almost nobody talks about it)

This is the forgotten hormone, yet it’s vital for:

• confidence

• mental clarity

• motivation

• libido

• stress resilience

• energy

• muscle maintenance (muscle = better metabolism + better blood sugar control)

When testosterone is low, you might notice:

• flatness

• lack of drive

• poor focus

• lower mood

• more intense cravings

• “can’t be bothered” energy

This is a huge contributor to both mood swings and brain fog.

Cortisol becomes harder to regulate

Perimenopause reduces your stress tolerance. Your cortisol may spike easily, even from small triggers, and the recovery takes longer.

This affects:

• blood sugar

• sleep

• irritability

• cravings

• mental clarity

• emotional capacity

Insulin sensitivity shifts

This is why you may suddenly:

• crave carbs

• lose energy after meals

• feel hungrier

• experience mood dips linked to blood sugar swings

Now that you understand the internal landscape, let’s move into the part that actually helps you feel better: real-world nourishment.

Real-World Nutrition Foundations That Support Mood and Brain Function

This isn’t about rigid rules, detoxes, cutting out foods, or calorie counting. This is about stabilising your hormones, protecting your energy, and giving your brain the fuel it needs to function.

Let’s keep it beautifully simple and completely doable.

1. Start with 30g Protein at Every Main Meal

This one shift alone can change everything.

Protein helps:

• stabilise blood sugar (hello steady mood!)

• reduce cravings

• support hormone balance

• improve focus

• increase satiety

• maintain muscle (which helps insulin and testosterone levels)

Most perimenopausal women under-eat protein without realising, especially at breakfast and lunch, which makes mood swings sharper and brain fog heavier.

30g protein looks like:

• 2–3 eggs + Greek yoghurt

• 200g Greek yoghurt with seeds and berries

• A chicken breast

• Salmon or tofu stir-fry

• Lentil/chickpea stew

• A protein smoothie made with yoghurt, milk, and seeds

Your brain needs stability, and protein provides it.

2. Add Healthy Fats for Mood Regulation and Cognitive Support

Your brain is 60% fat, so it makes sense that nourishing fats support clearer thinking and emotional steadiness.

Focus on:

• olive oil

• nuts & seeds

• avocado

• oily fish

• tahini

• nut butters

These fats help regulate hormones, reduce inflammation, and support brain structure, essential for easing brain fog.

3. Prioritise Fibre

Your gut and brain are in constant communication. So when your gut is supported, your mood follows.

Fibre helps:

• regulate blood sugar

• support healthy digestion

• feed your gut bacteria (which impact mood + clarity)

• keep energy steady

Aim for 30g a day through:

• fruit (especially berries, apples, pears)

• veg

• beans & lentils

• whole grains

• nuts & seeds

This is key in any “brain fog diet perimenopause” approach.

4. Add Magnesium + B Vitamins for Stress and Clarity

These nutrients support:

• mood regulation

• emotional resilience

• hormonal function

• energy production

• cognitive function

• sleep quality

Food sources include leafy greens, nuts, seeds, legumes, eggs, dairy, and whole grains. Supplements can help, but should be personalised.

5. Calm Blood Sugar

You don’t need to avoid carbs. You don’t need to go keto. You don’t need to earn your food. You simply need a gentle rhythm…

Protein + fat + fibre → THEN your carbs.

This slows down absorption, steadies mood, reduces emotional eating, and supports cognition.

It’s practical. It’s achievable. It’s not diet culture, it’s hormone support.

6. Eat Regularly

Many women unintentionally under-eat during perimenopause because they:

• feel rushed

• lose appetite

• skip meals

• aren’t sure what to eat

• rely on caffeine

This leads to:

• irritability

• low mood

• afternoon crashes

• binge eating

• night-time overeating

A steady rhythm of meals and snacks every 3–4 hours keeps your nervous system and brain beautifully supported.

7. Hydrate Properly

Even mild dehydration affects attention, memory, and mood. Aim for 1.5–2 litres of water daily, more if night sweats are intense.

Use whatever makes it easier:

• sparkling water

• herbal teas

• a big bottle on your desk

• adding cucumber or lemon

8. Support Your Nervous System When You Eat

Tiny changes make a massive difference:

• avoid eating on the go

• pause for 3 slow breaths before meals

• chew more slowly

• sit down when possible

These small habits improve digestion, reduce stress hormones, and increase clarity.

9. If You’re Taking (or Considering) GLP-1 Medications

These meds can help with weight and cravings, but they also suppress appetite, sometimes too much.

This can lead to:

• low protein

• reduced muscle

• low energy

• increased brain fog

• more mood swings

If you’re on GLP-1s, please prioritise:

• 30g protein

• nutrient-dense meals

• regular eating

• magnesium + B-vitamins

• hydration

You deserve nourishment, not restriction.

10. Your Self-Talk Matters More Than You Realise

Low mood, irritability, and forgetfulness can make you feel like you’re failing. Please hear this with tenderness, you’re not failing. You’re transitioning. You don’t need to be perfect. You don’t need to be disciplined. You don’t need to “get it together.” You need support, nourishment, steadiness, and compassion.

What This Looks Like in Real Life

If you want a simple starting point, begin here:

✨ 30g protein at each meal

✨ Healthy fats daily

✨ 25–30g of fibre✨ Balanced carbs, not restricted carbs

✨ Hydration

✨ Consistent eating

✨ Magnesium & B-vitamins

✨ A calmer eating rhythm

These foundations are the heart of any supportive perimenopause mood food plan, and form the basis of the most effective food for brain fog approach. Small steps. Real-world changes. No guilt. No punishment.

If you’re ready to feel clearer, calmer, and more energised, I can help. Perimenopause is confusing enough. You shouldn’t have to figure it out alone, especially when you’re juggling symptoms, stress, and the mental load of daily life.

If this blog resonated and you want help that feels compassionate, practical, and fully tailored to you then book in a complimentary clarity call with me.

It’s relaxed, friendly, and completely pressure-free. Just a safe space to share what’s going on and explore the personalised steps that can help you feel more like yourself again. Click here to book.