The infection caused by the SARS-CoV-2 virus, known as COVID-19, affects the body in numerous ways beyond the respiratory system. Many people who contract the virus experience a noticeable change in their desire to eat. This reduction in appetite is a frequently reported symptom that can complicate recovery by limiting necessary caloric and nutrient intake. Understanding the specific ways COVID-19 suppresses hunger involves looking at both the body’s internal immune response and the virus’s effect on the sensory system.
Appetite Loss as a Common COVID Symptom
A significant portion of COVID-19 patients report a substantial reduction in appetite, medically described as clinical anorexia. Studies indicate that up to nearly 60% of individuals hospitalized with the infection experience a loss of hunger. This makes appetite loss one of the more common non-respiratory symptoms, often appearing alongside fatigue, fever, and headache.
The severity of the illness often correlates with the duration of this symptom. In mild or moderate cases, the median duration of appetite loss is often around ten days. However, individuals with severe disease may experience suppressed appetite for up to 14 days or more. This sustained lack of interest in food can quickly lead to unintended weight loss and malnutrition, slowing the overall recovery process.
Biological Mechanisms Driving Reduced Hunger
The body’s primary response to SARS-CoV-2 infection is an immune mobilization that directly suppresses hunger. The immune system releases pro-inflammatory cytokines, such as Interleukin-6 (IL-6) and Tumor Necrosis Factor-alpha (TNF-alpha), as part of the systemic inflammatory reaction.
These proteins travel through the bloodstream and signal the hypothalamus, the brain’s control center for appetite and metabolism. Elevated cytokine levels interfere with the normal signaling pathways that promote hunger. This mechanism conserves energy during illness, shifting resources toward fighting the infection rather than digesting food.
This appetite suppression is part of a broader phenomenon known as “sickness behavior,” which also includes increased sleep and lethargy. This systemic response occurs regardless of whether a person can taste or smell their food. The hyper-inflammatory state is strongly associated with a sustained loss of appetite, and higher levels of inflammatory markers suppress the desire to eat more aggressively.
How Loss of Taste and Smell Affects Eating
COVID-19 frequently affects the senses of taste and smell, which are crucial for food enjoyment and voluntary intake. Loss of smell (anosmia) is a hallmark symptom, affecting about one-third of patients, while loss of taste (ageusia) is also common. These sensory deficits make food seem bland or unappealing, leading to reduced consumption.
The virus attacks supporting cells in the nasal cavity, disrupting signals sent to the brain’s olfactory bulb. Since approximately 80% of perceived taste is actually smell, the inability to detect food aromas significantly diminishes the pleasure of eating. This sensory disruption can lead to an aversion to food, even if systemic hunger has returned.
Patients also report dysgeusia (altered taste) or parosmia (smells perceived as foul or unpleasant). When food tastes metallic, rotten, or simply wrong, the psychological barrier to eating becomes substantial. This sensory reduction in food intake independently contributes to weight loss and the risk of malnutrition.
Strategies for Maintaining Nutrition During Recovery
When appetite is suppressed, the focus must shift from eating large meals to prioritizing nutrient density and consistency. Eating small, frequent portions throughout the day, aiming for six small meals or snacks, ensures a steady supply of calories and nutrients.
Prioritize Calorie and Protein Intake
Prioritizing high-calorie and high-protein foods supports immune function and protects against muscle wasting during recovery. Examples include nuts, nut butters, avocados, eggs, and Greek yogurt. If chewing is difficult or energy is low, liquid nutrition maximizes intake with minimal effort. This includes smoothies made with protein powder, milk, or specialized meal replacement drinks.
Managing Sensory Changes
Experimenting with flavor is necessary when taste and smell are impaired. If senses are dulled, incorporate strong flavors like lemon, ginger, herbs, or spices to make food more palatable. Conversely, if nausea is a problem, bland options like rice, plain chicken, or toast may be better tolerated.
Hydration and Medical Monitoring
Staying well-hydrated is paramount, so sip on water, broths, or sports drinks frequently throughout the day to prevent dehydration. If an individual experiences significant, rapid weight loss or cannot maintain fluid intake, immediate medical intervention, such as dietary consultation or supplemental feeding, may be necessary.