Mindly Different

Understanding Cognitive Energy and Nutritional Needs

The brain is only about 2% of the body’s weight, yet it consumes around 20% of the body’s total energy every single day. That alone tells us something profound:

Thinking is metabolically expensive.
Feeling is metabolically expensive.
Self-regulation, decision-making, attention, planning, language, movement, and sensory processing are all metabolically expensive.

Every moment, your brain is budgeting energy – allocating it where it’s needed most, prioritizing survival and essential functions first, and everything else second. Understanding what the brain needs – and why – can transform the way we approach food, mood, and cognitive well-being.

But this knowledge isn’t something most of us grow up with. I certainly didn’t.

I was raised in an environment where nutrition wasn’t discussed, explained, or even understood as a concept. Food was mainly about survival and affordability: overcooked carbohydrates were the staple because they were cheap, filling, and familiar. Large amounts of simple sugars were considered not only normal, but an obligatory part of childhood. A sugary treat was a reward, a comforter, a distraction, a tool to soothe distress – even though the aftereffects on mood, skin, and dental health were difficult to ignore.

There was no framework for understanding why these foods could make me foggy, irritable, or overstimulated. Nobody talked about the brain, chemistry, or long-term energy stability. Nutrition wasn’t a field of knowledge, it was just pain quotidien.

It took time – years of self-education, curiosity, and eventually formal study – to understand the science behind nutrition. And it was diving into neurochemistry that finally shifted everything for me. When I saw how directly nutrients shape attention, mood, memory, resilience, and even identity, the connection became undeniable.

Food was no longer just food. It was a biological conversation with the brain.

What the Brain Needs Most: A Neurobiological Overview

When we talk about “brain energy”, we are talking about several intertwined systems:

• Glucose metabolism
• Neurotransmitter synthesis
• Mitochondrial function
• Blood flow and oxygen delivery
• Hormonal regulation
• Micronutrient availability

Each of these systems relies on nutrition in very specific ways.

And the brain always prioritizes its most essential functions first.
That means: if nutrients are insufficient or irregular, the brain will steal energy from cognitive functions to power survival systems.

This is why you may feel:

• mentally foggy
• overwhelmed by decisions
• unable to focus
• emotionally reactive
• exhausted without explanation

Glucose: The immediate fuel
Neurons rely heavily on glucose to maintain electrical activity. Because the brain cannot store it, it needs a steady supply. Sharp rises and drops – like the ones caused by simple sugars – can create equally sharp changes in mood and cognitive clarity. This explains why we can swing from hyperactivity to sudden fatigue after sweets.
Unstable blood sugar affects the prefrontal cortex, the region responsible for attention, planning, working memory, impulse control, and emotional regulation.

This is one reason why both neurodivergent individuals and people recovering from neurological injury often feel cognitively drained: their energy demand is higher, and their metabolic stability is more fragile.
Stable blood sugar = stable thinking.

Mitochondria: The Powerhouses That Keep Your Mind Awake

Every thought, every emotion, every movement requires ATP – the energy molecule made inside mitochondria.

Neurodivergent brains and recovering brains often show increased metabolic load because they recruit more neural pathways to complete the same task. This means they need more ATP, more oxygen, more micronutrients, and more recovery time.

Mitochondria rely heavily on nutrients such as:

• B vitamins
• magnesium
• iron
• omega-3 fatty acids
• antioxidants such as vitamin C, vitamin E, and polyphenols

Without these, energy production slows down – and cognitive fatigue appears quickly.

This is why on certain days even reading an email, listening to someone speak, or trying to multitask can feel like climbing a mountain.

Healthy fats: Structural nourishment
The brain is nearly 60% fat by weight. Omega-3 fatty acids, such as DHA, are essential for building cell membranes, supporting synaptic plasticity, and regulating inflammation. Diets low in healthy fats are strongly linked to cognitive fatigue and emotional instability.

Amino acids: Neurotransmitter building blocks
Neurotransmitters – the brain’s chemical messengers – are built from proteins.

For example:

• Serotonin (mood, calm, emotional balance) is made from tryptophan.
• Dopamine (motivation, focus, reward) is made from tyrosine.
• GABA (calming, inhibitory control) requires glutamate and B6.
• Acetylcholine (memory, learning) requires choline.

When protein intake is too low or irregular, neurotransmitter production drops, and cognitive symptoms follow.

This can look like:

• irritability
• low motivation
• difficulty focusing
• emotional volatility
• difficulty retaining information
• sensory overwhelm

Again: biology, not character.

Micronutrients: The silent catalysts
Vitamins and minerals don’t provide energy on their own, but they activate the enzymes that allow neurons to function.
For example:

• B vitamins support energy metabolism and neurotransmitter synthesis
• Magnesium regulates stress circuits and reduces excitability
• Iron transports oxygen to the brain
• Zinc supports memory and synaptic plasticity
• B12 and folate are needed for myelin and energy metabolism
• Choline supports memory and cellular repair

When even one of these is too low, cognitive load increases – sometimes dramatically.

Nutrient insufficiencies don’t always look like illness. Sometimes they look like:

• “I can’t think”
• “I can’t remember words”
• “Everything feels too much”
• “Why am I so tired?”
• “I feel disconnected”

Your brain is not failing you.
It is signaling a need.

Why Neurodivergent and Recovering Brains Get Drained Faster

Neurodivergent brains often:

• engage more neural circuits to perform the same task
• require more metabolic resources for self-regulation
• experience greater sensory load
• use more energy to filter information, noise, and distraction
• fatigue faster under stress or social demand

This means their nutritional needs – especially for stable glucose, protein, omega-3s, and minerals – may be higher than standard recommendations.

Supporting these needs can reduce cognitive fatigue, emotional reactivity, overwhelm, and burnout.

Why Some Foods Make You Feel Clear – and Others Don’t

From a neurobiological perspective, stable, nutrient-dense foods offer steady energy to the prefrontal cortex, the brain’s decision-making center. In contrast, highly processed carbohydrates trigger rapid blood-sugar fluctuations that interfere with executive functioning and emotional stability.

This is why:

• When you eat only fast carbohydrates your brain gets a glucose spike – then a crash. You may feel irritable, foggy, shaky, or overwhelmed soon after.
• When you skip breakfast your prefrontal cortex goes offline, focusing becomes hard, emotions become louder, and decision-making becomes slower
• When your diet is low in omega-3s, neural communication slows down, increasing the risk of mood dips and concentration difficulties.
• When you eat balanced meals with protein + complex carbs + healthy fats, blood sugar stabilizes for hours, supporting clear thinking and steadier emotions.
• When you are low in magnesium, your nervous system becomes more reactive and less able to return to calm after stress.

Understanding this isn’t about moralizing food choices. It’s about recognizing the biological reality: your brain performs differently depending on what you feed it.

A Personal Turning Point

Learning this science didn’t shame me for how I ate growing up – it offered compassion. It helped me understand that my body and brain were reacting exactly as biology predicts when given fuel that spikes, crashes, or lacks essential nutrients.

Realizing this gave me a deeper respect for nutritional rules. They were not arbitrary restrictions or trends. They were ways of supporting a brain that works tirelessly every second of my life.

Today, the knowledge feels empowering rather than restrictive.
It transforms food into a tool for clarity, steadiness, healing, and cognitive resilience.

And I wish someone had explained it to me sooner.

By Nataliya Popova
Mindly Different – Coaching for the beautifully different mind