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 brains. Irregular feeding times have been shown to contribute to poor mental health, including depression and anxiety, as well as cardio-metabolic disease and weight gain.
Fortunately, it is possible to use our eating rhythms to limit negative mood and increase mental health. As a doctoral student in the field of neuropsychiatry and a psychiatrist studying nutrition and mood disorders, our research focuses on investigating the impact of eating rhythms on the brain.
Sign up to get counterintuitive, surprising and impactful stories delivered to your inbox every Thursday
Here’s how it works: The circadian clock system is responsible for aligning our internal processes at the optimal times of the day based on environmental signals such as light or food. Humans have developed this wiring to meet energy needs that change a lot during the day and night, creating a rhythmic pattern to our eating habits that follows the sun’s schedule.
Although the master clock manages metabolic function during the day-night cycle, our eating rhythms also affect the master clock. Digestive tissues have their own clocks and show regular fluctuations in functioning over the 24-hour cycle. For example, the small intestine and liver vary throughout the day and night in terms of digestive, absorption and metabolic capacity.
When the primary circadian clock in the brain is out of sync with food rhythms, it affects the brain’s ability to function fully. Although the brain represents only 2% of our total body mass, it consumes up to 25% of our energy and is particularly affected by changes in calorie intake. This means that abnormal meal times are bound to have adverse health outcomes.
Food and mood
Although the underlying mechanisms are still unknown, there is an overlap between the neural circuitry that governs food and mood. In addition, 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 dopamine levels. Altered eating rhythms are believed to contribute to poor mood maintenance.
Irregular eating can also play a role in the complex underlying causes of mood disorders. For example, individuals with depression or bipolar disorder exhibit disturbed internal rhythms and irregular meal times, which significantly worsen mood symptoms. Additionally, shift workers, who tend to have irregular eating schedules, show increased rates of depression and anxiety compared to the general population. Despite this evidence, assessment of eating rhythms is currently not part of standard clinical care in most psychiatric settings.
Optimization of eating rhythms
So what can be done to optimize our eating rhythms? One promising method we have come across in our research is limited-time eating (TRE), also known as intermittent fasting.
TRE involves limiting the eating window to a certain amount of time during the day, typically 4 to 12 hours. For example, choosing to eat all meals and snacks in a 10-hour window from 9am to 7pm reflects an overnight fasting period. Evidence suggests that this method optimizes brain function, energy metabolism and healthy signaling of metabolic hormones.
TRE has already been shown to 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 regularly is also helpful 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 24/7 world filled with artificial light and 24/7 access to food. This makes the effects of disturbed eating patterns on mental health an important topic for modern life. As further research provides data on the assessment of eating rhythms in individuals with mood disorders, integrating eating rhythm treatment into clinical care could significantly improve patients’ quality of life.
For the general population, it is important to increase public knowledge on accessible and affordable ways to maintain healthy diets. This includes paying attention not only to the content of meals but also to eating rhythms. Aligning eating rhythms with the solar schedule will have lasting benefits for general well-being and may have a protective effect against mental illness.
This article was republished by The Conversation under a Creative Commons license. Read the original article.