I have a runny nose, a headache, and I feel like I have a cold. On sick days, I relax on the sofa. Then reach for a snack.
Appetite is often reduced when sick. So why do we sometimes crave sweet treats and carbohydrate-filled comfort foods?
Food craving goes beyond the mere desire to eat and involves a complex combination of emotional, behavioral, cognitive and physiological processes. Whether we need an immediate source of energy or temporary relief from discomfort, our bodies and minds work together to determine food preferences.
Here, we explore the science behind why our bodies crave sugar and carbohydrates, especially when sick.
strengthen the immune system
When disease strikes, our immune system kicks in and needs extra energy to fight off invaders.
This increased activity often leads to increased metabolic rate, energy demand, and nutritional requirements.
Sugary treats and carbohydrates provide a quick source of energy and can meet this growing demand.
However, while a high-sugar diet during illness may help meet increased metabolic demands, it can also exacerbate immune and inflammatory responses and impede recovery.
In the long term, high-sugar diets promote chronic inflammation, alter gut microbiota composition, and are associated with chronic disease. Aim for a balanced intake of fruits, vegetables, fiber, protein and low-glycemic carbohydrates for a well-functioning immune system.
Being sick puts stress on your body. Mild or severe acute stress, such as that seen in illness, increases the “fight or flight” hormones adrenaline and cortisol. This mobilizes stored energy to meet increased demand, but may also suppress appetite.
Long-term stress can upset your energy balance, leading to nutritional deficiencies and changes in gut and brain function. This may lower a person’s sugar and salt craving thresholds and increase their preference for energy-dense foods.
The stress hormone cortisol increases the preference for high-calorie, comfort foods and may temporarily reduce stress.
brain reward system
Comfort foods stimulate the brain’s reward system, releasing feel-good neurotransmitters such as dopamine and serotonin.
However, the “sugar rush” is often short-lived and can lead to decreased alertness and increased fatigue within an hour of ingestion.
The relationship between carbohydrates (which the body converts to sugar) and serotonin began in 1971, when researchers found elevated tryptophan (a precursor to serotonin) levels in the plasma and brain of rats after being fed a carbohydrate-rich diet. You can trace your discoveries back.
Subsequent studies in humans have established links between carbohydrates and mood, particularly in relation to obesity, depression, and seasonal affective disorder. Serotonin-enhancing therapies have since been shown to reduce carbohydrate intake.
Surprisingly, about 90% of serotonin production takes place in the gut. The vast microbial population in our gut has powerful effects on immunity, metabolism and appetite.
A recent mouse study also identified specific microbes associated with excessive sugar intake after antibiotic treatment.
Some people eat less when they are sick
Not everyone craves sugar and carbs when sick. Some people eat less for a number of reasons.
They don’t have much of an appetite. Ghrelin (the “hunger” hormone) levels may be elevated initially, but nausea, fatigue, and malaise can suppress appetite if the illness persists.Critically ill patients have reduced dietary intake and are at risk of malnutrition
metabolic adaptation.The body may slow down certain metabolic processes to conserve energy, reducing overall calorie requirements.
Changes in taste perception. Taste is an important factor that influences both appetite and energy intake.Alterations in taste and smell are common symptoms of illness, and were also common with COVID-19.
Consuming liquids such as water, tea, and soup may be more appealing and manageable than solid foods. These liquids provide hydration but contribute little to caloric intake.
Hayley O’Neill, Assistant Professor, School of Health Sciences and Medicine Bond University
This article is republished from The Conversation under a Creative Commons license. Please read the original article.