Most of us consider hunger to be the rumblings of the stomach with strong contractions and an insatiable desire to eat but hunger actually starts well before these symptoms arise. While hunger is not a disease, like any physiological state that signifies a need, there will be accompanying signs and symptoms that can sometimes be confusing. Nausea is one such symptom and often we will quickly associate it with an illness rather than hunger.
Why does nausea occur with hunger?
The vomiting centers in the brain are activated by a number of different stimuli. Gastrointestinal irritation is the most well known one but movement, tastes, smells, images and even sounds as well as emotions can also trigger it. Nausea is often a prelude to vomiting although in rare instances a person may vomit without any preceding nausea. Therefore nausea is similarly triggered by the same stimuli, and sometimes even weaker stimuli can trigger nausea but not elicit vomiting.
Nausea with hunger is a well known symptom. It may precede the borborygmi (stomach noises like rumbling and growling) that is associated with the strong stomach muscle contractions, which we commonly refer to as hunger pangs. In fact these hunger pangs may arise as late as 12 to 24 hours after the last meal. Excessive salivation, constantly thinking about food and even lightheadedness and fatigue that is associated with hunger may be later symptoms than nausea.
Causes of Nausea Hunger
Nausea is a sensation of wanting to vomit. The sensation is perceived by the brain and not the digestive tract although it can trigger strong contractions of the upper gastrointestinal tract just before vomiting itself occurs. Hunger is preceded by low blood glucose levels and it is this lower than normal glucose levels that may stimulate the sensation of nausea well before hunger pangs arise.
The most obvious cause of nausea hunger is the lack of food intake for a period of time. Contrary to popular belief, humans should not be eating just three square meals a day. Instead a constant intake of small amounts of food may be better in maintaining glucose levels without requiring the body to call up reserves of nutrients in the body. By doing with so, hunger can be averted as well as the consequences of overeating due to hunger.
The body’s requirement for calories depends on the level of physical activity. More active people will require more calories in a day whereas less active people can do with fewer daily calories. When the level of physical activity (output calories) exceeds the intake of food (input calories) then hunger may arise even though a person may have eaten within their regular meal times.
The dangers of extreme dieting is well known and while some people may still partake in risky weight loss programs, the more sensible approach is a calorie-restricted diet along with a suitable exercise program. Attempting to drink water, use substances to suppress the hunger sensation or just ignore the hunger will lead to unpleasant symptoms like nausea. Ultimately a person will eat a larger meal than they may have had they eaten small amounts of food consistently throughout the day.
A commonly ignored reason for nausea and hunger even after eating is gastroesophageal reflux disease (GERD). The backward flow of the acidic stomach contents that is often referred to simply as acid reflux irritates the lining of the esophagus. This irritation sends signals to the central nervous system and elicits the sensation of nausea. Heartburn is also felt but this is the pain sensation as a result of esophageal inflammation due to contact with the acid. These symptoms may at times be incorrectly perceived as hunger.
Gastritis and Peptic Ulcers
Inflammation of the stomach wall (gastritis) and open sores in the wall of the stomach or duodenum (peptic ulcers) are other reasons for the sensation of nausea along with hunger. This often leads to changes in eating habits but meal may not necessary allay these symptoms. Sometimes the symptoms like nausea and upper abdominal pain may in fact worsen after eating as is the case when there is hunger.
In hyperthyroidism (also referred to as thyrotoxicosis or simply as an overactive thyroid), the high levels of circulating thyroid hormones increases the metabolism. As a result a person will require more calories and therefore feel hunger sooner than expected. Nausea may signal the need for a constant intake of calories to cater for the body’s increased metabolic demand.
Nausea is a common symptom in hypoglycemia (low blood glucose levels). It is most prominent when the blood glucose levels are very low and accompanied by pallor (paleness), sweating and dizziness. However, even moderately low glucose levels may present with nausea. Lack of food intake may not always be the cause. For example, blood glucose levels can drop in diabetics, especially if antidiabetic medication is used inappropriately.
Drugs and Toxins
Nausea is one of the most common side effects experienced with medication. The drug components may stimulate an area in the brain known as the chemoreceptor trigger zone (CTZ), irritate lining of the stomach or increase stomach acid production. Other substances, including illicit substances, alcohol and even poisons, can also cause similar effects and the gastrointestinal irritation along with nausea may be mistaken for hunger.
Nausea is a well known pregnancy symptom even if there is no vomiting in the early parts of the day (morning sickness). It may not only be a problem in the first weeks of pregnancy or first trimester but may be ongoing due to the high levels of pregnancy hormones. Acid reflux is also common in pregnancy which may cause nausea and hunger sensations. Similarly the increased demand for nutrients by the growing fetus may lead to constant hunger.
Although nausea could be psychogenic, it is important to first identify underlying physical causes. Nausea is one of the common symptoms associated with psychological stress, especially with anxiety and nervousness. Psychological stress can also affect the body in several ways where nausea and hunger sensations may be apparent. Eating disorders are an obvious cause due to the poor eating habits.