Body’s Stress Response Impacts Eating Habits

The Relationship Between  Nervous System Dysregulation And Food Intake

The Nervous System: Your Body’s Command and Control Center

From coordinating your heartbeat to enabling you to solve complex puzzles, the nervous system is the ultimate communication network of your body. It orchestrates everything from your physical movements and reflexes to your thoughts, emotions, and memories. Let’s explore how this fascinating system is organized, why it’s so essential to your overall well-being, and the effects on food intake.

Central vs. Peripheral: The Two Main Divisions

The Central Nervous System (CNS) consists of the brain and spinal cord.  The brain is the mastermind of all bodily functions, responsible for cognition, emotions, memory, and conscious thought.  The Spinal Cord is a highway of nerve fibers that connects the brain to the rest of the body, facilitating quick reflexes and serving as a communication conduit.

The Peripheral Nervous System (PNS) encompasses all the nerves that lie outside the CNS. It’s subdivided into 2 parts: the Somatic Nervous System, which governs voluntary movements and relays sensory information and the Autonomic Nervous System (ANS), which regulates involuntary functions like heart rate, digestion, and temperature control. The ANS further divides into 2 parts: sympathetic (mobilized energy) and parasympathetic (rest and digest).

Introduction to Polyvagal Theory

Polyvagal Theory, described by Dr. Stephen Porges in the 1990s, provides a revolutionary understanding of how our nervous system influences our emotions, social behavior, and ability to cope with stress. It expands upon the traditional 2 parts of the autonomic nervous system (ANS) by identifying a third component—the social engagement system—which plays a crucial role in regulating our responses to safety, danger, and life-threatening situations.

The Social Engagement System (Ventral Vagal State) – Safety & Connection

The Social Engagement System, controlled by the ventral (front) vagus nerve, is activated when we feel safe, calm, and socially connected.  It allows us to engage in positive social interactions, experience emotions like love and trust, and maintain a balanced physiological state.  The heart rate and breathing are relaxed, facial expressions and vocal tone supporting communication, and the ability to think clearly and connect with others.

Fight or Flight (Sympathetic Nervous System) –Mobilization of energy

During times of safety and in balanced unity, the Ventral Vagal and the Sympathetic Nervous System (SNS) work together, allowing us to take action, engage, play, and complete tasks.

When we perceive danger or stress, the SNS activates fully. This system prepares us to fight (defend ourselves) or flee (escape the threat). Our heart rate increases with rapid breathing, there is heightened alertness, and an energy boost for action. Other possible body reactions include anxiety/panic, racing thoughts, unable to focus, losing patience, angry or aggressive behavior, and impulsive actions.

Shutdown and Freeze (Dorsal Vagal System)- Immobilization

During times of safety and in congruence with the Ventral Vagal State, the Dorsal Vagal System allows for recuperative rest and relaxation, digestion, and metabolizing emotions and experiences.

When the brain perceives an extreme threat (such as trauma or overwhelming fear), or if the sympathetic system (fight or flight) didn’t work, the dorsal (back) vagus nerve takes over, causing a freeze or shutdown response.  This state is linked to depression, dissociation, and numbness. The heart rate is slowed and breathing is shallow, feelings of disconnection, withdrawal, isolation, or numbness, and can lead to a total collapse.

Nervous System Survival States

The nervous system’s survival states—fight, flight, and freeze—were designed to protect us in true emergencies, like escaping danger or physical harm. However, in today’s world, these states are triggered far more often by non-life-threatening stressors such as work deadlines, social pressures, even traffic jams or chronic stress. Also, for many people whom have experienced trauma- whether through ongoing childhood adversity or a single overwhelming event— the development of their nervous system can be interrupted, causing it to remain in a prolonged state of hypervigilance or shutdown.

Nervous System Dysregulation and the Gastrointestional System

When the body perceives a threat, the sympathetic nervous system is activated. This response prioritizes survival over everything.  Being fully in the sympathetic state causes the following effects on the GI System:

• Reduced digestive activity: Blood flow is diverted away from the stomach and intestines to the muscles, heart, and lungs, leading to possible feelings of nausea and abdominal pain.

• Lower secretion of digestive enzymes: Hinders the breakdown and absorption of nutrients.

• Slowed or halted gastric motility: Digestion is slowed down, causing food to stay in the stomach for longer, leading to feelings of fullness, bloating, constipation and/or diarrhea, heartburn, loss of appetite, and discomfort.

While the sympathetic state response mobilizes the body for action of fight or flight. If the body hits a point of overwhelm,  the dorsal vagal state will be activated.  It is the body’s last-resort survival mechanism, leading to a functional shutdown to conserve energy and reduce perceived harm. Being fully in the dorsal vagal state can cause the following effects on the GI system:

• Severely Slowed or Stalled Gut Motility: Peristalsis (the wave-like movement of the intestines) significantly slows or stops, leading to constipation, bloating, or a sensation of fullness even when little has been eaten.

• Suppressed Appetite and Hunger Cues: The brain and gut become disconnected, and interoceptive awareness (the ability to sense internal signals like hunger and fullness) is diminished.  People in this state may report feeling numb, nauseated, or “just not hungry,” even when undernourished.

• Low Stomach Acid and Enzyme Secretion: Digestive secretions such as hydrochloric acid and pancreatic enzymes decrease, impairing the breakdown and absorption of nutrients. This can lead to malabsorption, indigestion, and a sensation of food “sitting” in the stomach.

Stress Response Impacts Eating Habits

Dysregulated Nervous System and Food Intake

When the nervous system is dysregulated, food intake often becomes disrupted in ways that reflect the body’s instinctive attempts to survive, not conscious choices about eating. In the sympathetic state, people may unintentionally skip meals, feel too anxious to eat, or go hours without realizing they haven’t eaten at all. Hunger cues often become muted, and physical sensations like a tight stomach, racing heart, or shallow breathing can make food feel unappealing or even nauseating. Meals may be rushed, eaten standing up, or grabbed on the go—more about function than nourishment. Some may rely on highly palatable foods—those rich in sugar, fat, or salt—for fast energy or comfort. Later, when the nervous system begins to come down from this activated state, there may be a rebound effect: emotional eating, grazing in the evening, or overeating as the body tries to replenish and self-soothe after prolonged depletion.

In contrast, a dorsal vagal “freeze or shut down” state reflects a more collapsed, immobilized response to overwhelm. Appetite may disappear altogether, and individuals may feel emotionally numb, fatigued, or disconnected from bodily sensations, including hunger and fullness. Food may lose its appeal entirely—nothing sounds good, and even the idea of eating or preparing a meal can feel overwhelming. When eating does occur, it may be mechanical and unfulfilling, or interrupted by early satiety, bloating, or nausea due to slowed digestive function. People in this state often go long periods without eating, not by choice, but because their body is in conservation mode. In both sympathetic and dorsal vagal states, the brain-body connection that supports intuitive eating becomes impaired, and the individual may feel confused or frustrated by their inability to eat “normally.”

These patterns are frequently misunderstood as a lack of willpower, disinterest in self-care, or intentional disordered eating. In reality, they are nervous system adaptations to environments where the body does not feel safe—a biological response, not a moral failing. Over time, chronic dysregulation can lead to malnourishment, disrupted metabolism, mistrust of internal cues, and shame around food behaviors that feel out of control or unpredictable. Healing begins by supporting nervous system regulation—through safety, connection, and compassionate care—so the body can shift out of survival mode and gradually return to a state where eating is intuitive, nourishing, and safe.

If you are experiencing nervous system dysregulation and it is effecting your relationship with food or food intake, reach out to us today!