Nutrition and Cognitive Performance: What You Eat Affects How You Lead

The average person makes roughly 35,000 decisions per day. Senior leaders make far more - many of them consequential. And yet most people give almost no thought to how they're fueling the organ responsible for making those decisions.

Blood Sugar and Decision Quality

One of the most direct connections between nutrition and performance is blood sugar regulation. When blood sugar drops - which happens after skipping meals, eating high-glycemic foods, or running on caffeine alone - the prefrontal cortex (responsible for executive function) is literally starved of glucose.

Studies have shown that judges make significantly harsher parole decisions right before meals (when blood sugar is low) than right after. The effect isn't subtle. It's measurable. And it plays out in every workplace, every day.

The Gut-Brain Connection

The gut produces approximately 95% of your body's serotonin - the neurotransmitter most associated with mood stability and emotional resilience. The gut and brain communicate bidirectionally via the vagus nerve, meaning the state of your gut microbiome directly influences your mental state.

Practical Nutrition for High Performance

• Start the day with protein (30–40g) to stabilize blood sugar and support neurotransmitter production
• Minimize refined carbohydrates and ultra-processed foods - they cause blood sugar spikes and crashes
• Eat omega-3-rich foods (salmon, sardines, walnuts, flaxseed) - DHA is the primary structural fat in the brain
• Stay hydrated: even mild dehydration (1–2%) significantly impairs cognitive performance and mood
• Eat consistently throughout the day - avoid the common pattern of skipping breakfast, pushing through lunch, and overeating at dinner