Eating is an essential part of human life and it turns out that not only what we eat but also when we eat can impact our brain. Irregular eating times have been shown to contribute to poor mental health, including depression and anxiety, as well as cardio-metabolic diseases and weight gain.
Fortunately, it is possible take advantage of our eating rhythms to limit negative mood and increase mental health. As a doctoral student in the field of neuropsychiatry and a psychiatrist who studies nutrition and mood disorders, our research focuses on investigating how eating rhythms impact the brain.
This is how it all works: the circadian clock system is responsible for aligning our internal processes at optimal times of day based on cues from the environment, such as light or food. Humans have evolved this wiring to meet energy needs that change a lot during the day and night, creating a rhythmic pattern in our eating habits that follows the time of the sun.
Although the master clock manages metabolic function during the day-night cycle, our eating rhythms also affect the master clock. The digestive tissues have their own clocks and show regular oscillations in their functioning during the 24-hour cycle. For example, the small intestine and the liver. vary throughout the day and night in terms of digestive, absorptive and metabolic capacity.
When the brain’s main circadian clock is out of sync with eating rhythms, it affects the brain’s ability to function fully. Although the brain is only two percent of our total body mass, it consumes up to 25 percent of our energy and is particularly affected by changes in calorie intake. This means that abnormal meal times are sure to have negative health outcomes.
food and humor
Although the underlying mechanisms are still unknown, there is an overlap between the neural circuitry that governs eating and mood. Additionally, digestive hormones exert effects on dopamine, a neurotransmitter that plays an important role in mood, energy, and pleasure. Individuals with depression and bipolar disorder have abnormal levels of dopamine. Disturbed eating rhythms are thought to contribute to poor mood maintenance.
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Irregular eating may even play a role in the complex underlying causes of mood disorders. For example, people with depression or bipolar disorder exhibit disturbed internal rhythms and irregular meal times, which significantly worsen mood symptoms. In addition, shift workers, who tend to have irregular meal times, demonstrate higher rates of depression and anxiety when compared to the general population. Despite this evidence, assessment of eating rhythms is not currently part of standard clinical care in most psychiatric settings.
Optimization of feeding rhythms
So what can be done to optimize our eating rhythms? One promising approach we’ve found in our research is time-restricted eating (ERT), also known as intermittent fasting.
ERT involves restricting the feeding window to a certain amount of time during the day, typically four to 12 hours. For example, choosing to eat all meals and snacks in a 10-hour period, from 9:00 am to 7:00 pm, reflects an overnight fasting period. Evidence suggests this approach optimizes brain function, energy metabolism, and healthy metabolic hormone signaling.
TRE has already shown prevent depressive and anxiety symptoms in animal studies designed to model shift work. The antidepressant effects of TRE have also been shown in humans. Eating at a regular time is also beneficial in reducing the risk of health problems such as obesity, diabetes, and cardiovascular disease.
Circadian rhythms in a 24-hour world
We live in a 24-hour world filled with artificial light and 24-hour access to food. That makes the effects of disturbed eating patterns on mental health an important topic for modern life. As more research provides data evaluating eating rhythms in people with mood disorders, incorporating eating rhythm therapy into clinical care could significantly improve a patient’s quality of life.
For the general population, it is important to increase public awareness of accessible and affordable ways to maintain a healthy diet. This includes paying attention not only to the content of meals but also to the rhythms of eating. Aligning eating rhythms with the time of the sun will have lasting benefits for general well-being and may have a protective effect against mental illness.
