It's not just about eating your greens. What you eat and drink during the working day has a measurable impact on your brain, your mood and your ability to think clearly under pressure.
Most of us know, on some level, that food affects how we feel. But the connection between what we eat and how we perform at work - our focus, our resilience, our emotional regulation, our ability to handle a difficult afternoon - is far more direct and far better evidenced than most people realise.
This isn't about clean eating or food guilt. It's about understanding a few key mechanisms that, once you're aware of them, start to explain a lot about why some days feel manageable, and others feel impossibly hard.
The Brain Runs on Food
The brain accounts for roughly 2% of body weight but consumes around 20% of the body's total energy. It is, metabolically speaking, extraordinarily hungry - and it is not indifferent to what it receives.
The brain's primary fuel source is glucose, derived from the carbohydrates we eat. But not all glucose is equal, and how that glucose arrives - in a steady flow or a sudden surge - makes an enormous difference to how the brain functions.
When blood sugar rises quickly (after a high-sugar snack, a white bread lunch, a handful of biscuits at 3pm), the brain gets a brief burst of energy followed by a sharp drop. That drop is experienced as fatigue, difficulty concentrating, irritability and a strong craving for more sugar. It's the classic afternoon slump - and it's not a matter of willpower. It's biochemistry.
When blood sugar rises slowly and steadily, from complex carbohydrates, protein, fibre and healthy fats, the brain receives a consistent, reliable energy supply. Focus is sustained. Mood is steadier. The capacity to handle pressure is noticeably better.
The Gut-Brain Connection
One of the most significant developments in nutrition science over the past two decades is our growing understanding of the gut-brain axis; the bidirectional communication network between the digestive system and the brain.
The gut contains around 100 million nerve cells and produces approximately 95% of the body's serotonin - the neurotransmitter most associated with mood, emotional regulation and the sense of wellbeing. This means that what happens in the gut has a direct and significant effect on how we feel mentally and emotionally.
A diet that disrupts gut health (high in ultra-processed foods, low in fibre and variety) is increasingly linked to higher rates of anxiety, low mood and cognitive difficulties. Conversely, research published in the journal BMC Medicine has found that dietary interventions focused on whole foods, vegetables, legumes and lean proteins can produce significant improvements in depression symptoms - in some cases comparable to the effects of medication.
This doesn't mean food is a substitute for mental health support. But it does mean that what we eat is a meaningful variable in our psychological resilience, one that's often overlooked in workplace wellbeing conversations.
Stress, Cortisol and Food
When we're under stress, the body releases cortisol, the primary stress hormone. In the short term, cortisol is useful: it sharpens alertness and mobilises energy. But chronically elevated cortisol, which is common in high-pressure working environments, has a range of effects that directly undermine performance.
One of the most significant is its effect on blood sugar regulation. Cortisol signals the liver to release more glucose into the bloodstream; an evolutionary response designed to fuel the fight-or-flight response. In a modern office, where the "threat" is a difficult meeting or a looming deadline, that extra glucose isn't burned off through physical activity. Instead, it contributes to blood sugar volatility, energy crashes and increased cravings for high-sugar, high-fat foods.
This creates a feedback loop: stress drives poor food choices, poor food choices destabilise energy and mood, and destabilised energy and mood make it harder to cope with stress. Breaking that loop through conscious nutrition choices - particularly during high-pressure periods - can have a meaningful impact on how resilient people feel day to day.
Hydration and Cognitive Function
Dehydration is one of the most underestimated factors in workplace performance. The brain is approximately 75% water, and even mild dehydration (a loss of just 1–2% of body weight in fluid) has been shown to impair concentration, short-term memory, reaction time and mood.
A study published in the Journal of Nutrition found that mild dehydration in women caused measurable reductions in mood, concentration and increased perceptions of task difficulty. A similar study published in the British Journal of Nutrition found comparable effects on working memory and cognitive performance in men.
Most people working in offices are mildly dehydrated for significant portions of the day - particularly those who rely on coffee as their primary fluid, since caffeine has a mild diuretic effect that increases fluid loss. The fix is simple, but the impact is real: consistent hydration throughout the working day supports clearer thinking, better mood and reduced fatigue in ways that are straightforward and well-evidenced.
Caffeine: Ally or Obstacle?
Most people's working day begins with coffee, and caffeine is genuinely useful - in moderation and at the right time. It blocks adenosine receptors in the brain, temporarily reducing the perception of tiredness, and has been shown to improve alertness, reaction time and certain aspects of cognitive performance.
The problems arise from how it's typically used in a workplace context: large quantities, consumed throughout the day, often replacing meals rather than accompanying them.
Caffeine on an empty stomach can spike cortisol levels and contribute to anxiety and irritability. Consuming caffeine after 2pm - for most people - disrupts sleep architecture, reducing the restorative deep sleep that is essential for memory consolidation, emotional regulation and next-day cognitive function. Poor sleep further elevates cortisol and increases cravings for high-sugar, high-fat foods the following day.
Understanding the relationship between caffeine, sleep and nutrition helps people use it as the useful tool it is, rather than relying on it as a substitute for actual energy.
The Five Areas Our Nutrition Workshops Cover
Glo's nutrition workshops are designed around the challenges that come up most consistently in modern workplaces, approached without pressure, guilt or unrealistic expectations.
Nutrition as self-care - moving away from all-or-nothing thinking and building sustainable habits that actually work within a busy life.
Avoiding burnout from the inside out - understanding the physical dimension of burnout and how food, blood sugar and energy management play a role.
Energy, focus and health at work - practical guidance on eating for consistent performance throughout the day, including meal timing, snacking strategies and hydration.
Supporting women through menopause - how hormonal changes affect energy, mood and cognitive function, and how nutrition can help manage the transition more comfortably.
Healthy at any size - a naturopathic approach that moves beyond dieting and focuses on building a healthier relationship with food and the body.
What the Evidence Says About Workplace Nutrition Programmes
The return on investment for nutrition-focused wellbeing interventions at work is well-documented. Research consistently shows that employees who eat well - particularly those supported by workplace programmes to do so - demonstrate lower rates of absenteeism, higher productivity and better emotional resilience.
The British Heart Foundation estimates the potential economic return on investment for UK businesses investing in workplace health initiatives at £4.17 for every £1 spent. Nutrition is a core component of that case.
A 2019 review published in Public Health Nutrition found that even minimal workplace nutrition interventions - such as simply increasing the availability of fruit - led to meaningful improvements in dietary habits, with increases in fibre intake and reductions in added sugar consumption. Effects extended beyond the individual sessions into daily eating patterns.
The evidence suggests that nutrition workshops work not just because of what people learn in the room, but because the workplace context gives people permission to prioritise their own health, something many find difficult to do when left entirely to their own devices.
Small Changes, Measurable Impact
None of this requires a wholesale lifestyle overhaul. The research is clear that small, consistent changes to eating patterns (more fibre, steadier blood sugar, adequate hydration, slightly less caffeine reliance) produce measurable improvements in energy, mood and cognitive performance over time.
The goal of a Glo nutrition workshop isn't perfection. It's giving people enough understanding of the mechanisms, and enough practical tools, to make slightly better choices slightly more often. Over weeks and months, that compounds into something significant - for individuals, and for the organisations they work in.
Bring a Nutrition Workshop to Your Team
Glo's nutrition workshops are delivered in-person or virtually, tailored to your organisation and led by experienced practitioners. Sessions are practical, evidence-based and designed to fit around real working lives.
View our Nutrition Workshop package or make an enquiry to discuss what would work best for your team.