This article reviews past literature related to the biological mechanisms that are activated during periods of fasting. It specifically focuses on the potential positive effects of fasting on mood.
Published in October 2013 in the journal Psychiatry Research. Access the original article here: Fasting in mood disorders: neurobiology and effectiveness. A review of the literature
A brief summary:
What were they interested in? The authors were interested in looking in the literature to understand if fasting was associated with improved mood or reduction in depression or anxiety symptoms.
What did they do? The authors note that looking for studies that specifically linked fasting with “mood” or “depression” was too limiting; therefore, they focused their efforts searching for literature and studies that show fasting’s effects on neuro-biological mechanism that have been linked to enhanced mood and improvement in depression and anxiety.
What did they find? Given the lack of controlled, high quality studies specifically linking fasting and mood, there isn’t a firm statement such as “fasting improves your mood” that can be drawn. However, there were several studies that suggested that fasting significantly enhanced brain pathways responsible for feelings of well-being.
What direction could be next? It isn’t know whether fasting affects these biological pathways in a long-term (persistent) way, or whether it is a short-term (transient) effect. A specific study that focusing SPECIFICALLY on fasting and its effects on mood could be used to answer this question. Until then, we have indications of effect, but not firm conclusions.
History of Fasting and Mood:
- Until recent times, humanity was used to large fluctuations in the availability of food
- This often led to periods of over-feeding and starvation
- Periodic fasting is still practiced around the world, although mostly for cultural or religious reasons
- Hippocrates offered fasting as a treatment of acute and chronic diseases
- Therapeutic fasting has been considered a safe medical practice for more than a century
- Deliberate fasting has been observed to increase mental alertness, sense of calm, and positive mood
- Mood alleviation may be related to an adaptive response promoting a search for food
Methods of This Study on Fasting and Mood:
- Checked scientific databases for articles related to fasting’s effects
- Then selected 92 relevant articles for review
- Important background: what is a review article?
- Research articles (primary sources) report the methods and results of an original study performed by the authors
- Review articles (secondary sources) synthesize and analyze research already conducted in primary sources, but don’t original research of its own
Mechanisms of Mood Improvement During Fasting:
- Long periods of fasting activate pathways in a similar way to a biological stressor
- Activates the hypothalamic-pituitary-adrenal axis (HPA)
- Mechanisms of this activation may include
- Reduced cerebral glucose
- Reduced insulin and leptin levels
- Changes in leptin levels has already been identified as a signal of biological adaptation to starvation, and is associated with mood disorders
- Sensation of hunger
- Previous studies have also shown that fasting increases the availability of serotonin
- Release of endorphins found after fasting
- May be due to improved sleep caused by fasting
- Production of ketone bodies
Proposed Benefits of the Relationship Between Fasting and Mood:
- Improvement in sleep quality
- Improved mood
- Improved concentration
- Decrease in migraine symptoms
- Decrease in pain sensation
Limitations to Keep in Mind:
- Need to perform randomized controlled clinical trials
- Findings are promising, but a direct relationship cannot be determined without meta-analysis
- Not possible given the heterogeneity of available studies
- Heterogeneity: variability in the methods and population used in the study that make it difficult to make direct comparisons of studies’ results
- Unclear if mood improvement is sustained over time or if it is a temporary effect
Other Fasting Flamingo Resources You May Enjoy:
- Why fasting bolsters brain power
- In this TED Talk, Mark Mattson, who currently serves as the Chief of Laboratory Neuroscience at the National Institute of Aging, discusses how intermittent fasting is good for your brain. He discusses both anecdotal and evolutionary evidence that fasting improves mental efficiency.
- The Fasting Talk, Breathe, and Distract Method
- In this article, fellow intermittent faster and author Mimi discusses one of her favorite strategies for getting through a tough fast. Mimi, who has already lost over 70 pounds through fasting, believes that the fasting lifestyle can be easy and fun, and we here at The Fasting Flamingo agree!
- Eat, Fast, Feast
- Why did most Christians stop fasting? And, is this ancient practice something the church should consider resurrecting? Dr. Jay W. Richards explores these interesting questions in his book as well as some of his own journey with fasting and a ketogenic diet.