When hunger strikes, it is often accompanied by an unexpected and unpleasant wave of symptoms, including dizziness, shakiness, irritability, and sometimes nausea. This common experience is not a sign of weakness but a powerful, natural physiological reaction as your body signals an urgent need for fuel. This chain reaction begins with the brain registering a critical energy shortage, which then triggers a cascade of systemic responses designed to restore balance.
The Body’s Energy Crisis
The primary fuel source for your brain and central nervous system is glucose, a type of sugar circulating in your bloodstream. When you go too long without eating, the concentration of this fuel begins to drop, a state known as hypoglycemia. Because the brain cannot store glucose, it is highly sensitive to even minor fluctuations in supply, and its function suffers quickly when levels dip.
This drop in energy supply causes classic cognitive symptoms of hunger, such as dizziness, mental fogginess, and difficulty concentrating. A blood glucose level below about 70 milligrams per deciliter (mg/dL) is the threshold where the brain begins to signal distress, warning that its main power source is running low.
The Fight or Flight Response to Hunger
Once the brain recognizes the energy crisis, it initiates a powerful counter-response to raise blood glucose levels quickly via the endocrine system. The body releases stress hormones, most notably adrenaline (epinephrine) and cortisol, associated with the “fight or flight” response. Adrenaline acts rapidly, signaling the liver to break down its stored energy, glycogen, and release it as glucose into the bloodstream.
This sudden surge of stress hormones produces the intense physical symptoms that often make people feel unwell. Adrenaline causes the heart to beat faster, induces sweating, and leads to the noticeable shakiness and anxiety sometimes called “hanger.” Cortisol works more slowly but prolongs the effect, helping the body mobilize fat and protein stores to create new glucose if the fasting continues.
Digestive System Contributions to Nausea
In addition to the systemic hormonal response, the digestive system itself can contribute to feelings of nausea or discomfort when the stomach is empty. The stomach operates on a predictable schedule and continues to produce digestive fluids, including hydrochloric acid, in anticipation of food. The hunger hormone ghrelin, which signals the brain to eat, also stimulates stomach motility and acid secretion.
Without food present to absorb or “buffer” this gastric acid, the concentrated fluid can irritate the sensitive lining of the stomach. This irritation can result in a burning sensation, cramping, or generalized queasiness, which is often misinterpreted as illness. For some people, this localized stomach discomfort is the most immediate and noticeable symptom of delayed eating.
When to Seek Professional Advice
While feeling unwell from hunger is usually a normal physiological response to delayed eating, severe, frequent, or unusual symptoms may warrant a conversation with a healthcare provider. If your symptoms are extreme, such as frequent fainting, severe vomiting, or if they are not relieved promptly after eating, a medical evaluation is prudent. These episodes could occasionally signal an underlying metabolic issue, such as early-stage Type 2 diabetes or reactive hypoglycemia.
Reactive hypoglycemia is a condition where blood sugar drops abnormally low within a few hours after a meal, often due to an over-release of insulin following high-carbohydrate consumption. Your doctor may perform tests to see if your symptoms are directly linked to low blood sugar and rule out other conditions. Persistent problems with low blood sugar may also be caused by certain medications, liver or kidney diseases, or metabolic problems that require specific management.
Management and Prevention Strategies
The most effective strategy for managing and preventing these uncomfortable symptoms involves stabilizing your blood sugar and avoiding long gaps between meals. Eating balanced meals that combine different macronutrients helps ensure a steady, sustained release of glucose into the bloodstream. Focus on complex carbohydrates, such as whole grains, fruits, and vegetables, which are digested slowly and prevent sharp blood sugar spikes and crashes.
Pairing these carbohydrates with protein and healthy fats, like those found in nuts or avocados, further slows digestion and promotes a feeling of fullness. Eating small meals or healthy snacks approximately every three hours can help maintain consistent energy levels and prevent the body from entering the stress-hormone-driven energy crisis. Keeping a small, emergency snack on hand, such as a piece of fruit or a handful of nuts, allows you to address the symptoms immediately if they arise.