I am not a nutrition expert, although I have studied the topic. I am simply a layperson—someone who has struggled with their weight, experienced what it’s like to be overweight, endured fasting without losing a single pound, and finally discovered what it means to feel good in my own skin. (So, what I’ve put together in this piece is nothing more than personal opinion, personal experience, and a summary of interesting insights I’ve read on the subject.)

Personal Observations on Nutrition and Well-Being

My personal experiences—and perhaps my background in biology education or my interest in sports—have led me to pay close attention to how my eating habits affect my overall well-being. I discovered early on that I am a stress eater, that I turn to sweets to ease anxiety, and that a carefully planned diet—calculated for calorie content, rich in fiber, regular, and tied to specific time windows—significantly increased my daily comfort level. This, in turn, helped me manage conflicts in my professional life, especially in leading a business.

In his book Sapiens, Yuval Noah Harari provides an intriguing explanation of why we crave high-calorie foods. He theorizes that, before the Agricultural Revolution, humans had limited access to calorie-dense foods. When they did find something like a fruit-laden tree, they had to eat as much as they could on the spot, not knowing when a stronger group might come along and take it away. Despite the Agricultural, Industrial, and now Technological Revolutions, very little time has passed in evolutionary terms, so our brains still operate on those ancient survival reflexes.

Understanding how my diet impacts my physical and emotional state is important to me. It brings me closer to understanding myself and enables me to support myself—and, by extension, my children and the leaders I mentor—in living a healthier, fuller life.

The Gut-Brain Axis

Traditional nutritional science often approached food’s impact through a functional lens, focusing on how the foods we consume affect physical health. However, as modern societies increasingly face stress, depression, and anxiety, the consumption of calorie-dense, unhealthy foods—like chips, sodas, energy drinks, and fast food—has become more noticeable.

At first glance, it’s hard to determine causality, if it exists at all. Do unhealthy foods increase the prevalence of psychological disorders, or do worsening mental health problems lead to poor dietary choices?

To explore this further, the field of nutritional psychiatry has emerged, examining the relationship between mental well-being and diet. Research has highlighted the role of serotonin, produced in the gut, in regulating mood and sleep. It has also shown that the microbiota in the gut (nearly 1,000 species of “good” bacteria) play a critical role in serotonin production. These findings have brought attention to the gut-brain axis—a bidirectional communication pathway between the gut and the central nervous system—and its role in how nutrition affects mental health.

Key Studies on the Gut-Brain Axis

Study 1: Gender Differences in Nutrition’s Impact on Emotional Well-Being
Research led by Lina Begdache at Binghamton University, New York, examined the psychological effects of nutrition with a focus on gender differences. The study involved 563 participants (48% male, 52% female) and highlighted that men’s mental well-being is more likely to erode when nutritional deficiencies arise, whereas women’s mental well-being is more closely tied to proper nutrition.

Study 2: Stress Resilience and Gut Flora
Animal studies have primarily explored the relationship between gut flora and behavior. One study (Postnatal microbial colonization programs the hypothalamic–pituitary–adrenal system for stress response in mice) found that eliminating gut flora in mice reduced their ability to cope with stress.

Study 3: Behavioral Changes via Gut Flora Transfer
In another study (The intestinal microbiota affect central levels of brain-derived neurotropic factor and behavior in mice), researchers transplanted gut flora from active mice into passive ones. The passive mice exhibited increased activity levels after the transplant, demonstrating behavioral changes influenced by gut microbiota.

Study 4: Using Bacterial Strains as Psychiatric Treatments
A further study (Bifidobacteria exert strain-specific effects on stress-related behavior and physiology in BALB/c mice) examined two strains of Bifidobacteria (B. longum 1714 and B. breve 1205) and found they alleviated anxiety in mice.

While these studies don’t definitively prove that bacteria can treat psychological disorders—or that diets targeting gut flora are effective—the results are promising.

Personal Reflections

Poor nutrition can negatively affect decision-making as a leader. In my case, unhealthy eating habits and irregular meals contributed to physical and emotional states that not only hindered my ability to make quick, effective decisions but also reduced my ability to manage stress over the long term.

As I’ve become more attentive to my current state in recent years, I’ve noticed patterns in how irregular eating affects me:

• Decreased Energy Levels: This is often the first sign. My face looks hollow, and I lack the motivation to exert effort in any area.
• Reduced Stress Tolerance: I become irritable and snappy, even over things that wouldn’t usually bother me.
• Emotional Instability: Irritability leads to a loss of balance and composure.
• Short-Term Thinking: With limited energy and patience, I start favoring simple, quick solutions over well-thought-out plans.

The most alarming part is how physical and emotional states intertwine, often without you realizing what’s happening. Poor eating habits make you irritable—perhaps a colleague’s work or a client’s questions suddenly annoy you, even though they wouldn’t normally bother you. It’s easy to mistake these reactions as justified when they’re really the result of your own depleted state.

This creates a negative decision-making spiral: stress and poor physical health impair your decision-making ability. Bad decisions then generate new stressors, which further worsen your mood and reinforce negative emotions, creating a self-perpetuating cycle.

This doesn’t just affect work—it continues at home as well.

The Bigger Picture

Ultimately, nutrition significantly impacts emotional well-being and decision-making abilities. My readings have shown me that modern research increasingly highlights how healthy eating is critical not only for physical but also for mental health.

In the end, adopting mindful eating habits and a healthy lifestyle can improve both personal and professional performance. It’s an investment every leader and decision-maker should make for a better, more balanced life.

The original article was published on the Vendler.hu blog.