How Hunger Games Bolster Brain Function

 Part 6 of “What Six Months of Soup Can Teach Me”

In many ways this installment of the blog on the benefits of modified intermittent fasting is the most fascinating.  It deals with the idea that the cognitive function of our brains actually improves during the times of sustained caloric reduction.  This interval refers to at least 12 hours where energy or caloric intake is substantially less than immediate needs.  Perhaps the easiest way to get to this state is the modified, intermittent fasting we have been discussing in this blog.

In this modified fasting state, the body shifts to an alternative energy mode of burning stored energy from body fat stores.  To do so it alters a diverse group of hormones and signaling molecules that actually help several of our systems, including the brain, actually function more efficiently.

While this may seem surprising, this trait was essential for man’s survival for most of our existence as we faced a constant challenge to regularly find/catch enough food up until approximately the past 200 years.  We are genetically wired to have heightened function during times of caloric restriction. 

The following quote from a Dr. Mark P. Mattson at the Laboratory of Neurosciences, National Institute on Aging in the medical journal, Aging Research Review explains this apparent dilemma:

“Because it evolved, in part, for success in seeking and acquiring food, the brain functions best when the individual is hungry and physically active, as typified by the hungry lion stalking and chasing its prey. Indeed, studies of animal models and human subjects demonstrate robust beneficial effects of regular exercise and intermittent energy restriction/fasting on cognitive function and mood, particularly in the contexts of aging and associated neurodegenerative disorders.”

Both animals and humans have required intense mental focus in the fasting state when they were in pursuit of food.  The linking of fasting to better brain function was inherent to survival.

The metabolic changes during the fasting state were thought to impart an advantage to the success of finding subsequent food either through hunting of gathering.  It appears this fasting state increases mental alertness that would be needed pursuing wild game.  This interesting video about Dr. Mattson’s research is about how mice who have an increased genetic pattern towards developing memory impairment and dementia can greatly reduce this tendency with periodic fasting. 

When the research is examined on caloric volume/intake the conclusions appear to be that a balance is needed.  There is a wealth of research correlating chronic caloric excess with chronic disease.  Obesity and diabetes, two well established diseases linked to chronic caloric excess are both important risk factors for dementia and Alzheimer’s disease.

Dr. Mattson summarized this best in his Aging Research Review paper:

“In addition to disengaging beneficial adaptive responses in the brain, sedentary overindulgent lifestyles promote obesity, diabetes and cardiovascular disease, all of which may increase the risk of cognitive impairment and Alzheimer’s disease.”

In contrast, there is a growing body of research finding that regular, intermittent negative energy balance or caloric deficit increases brain functioning and cognition.  Prominent brain researchers are now advocating intermittent fasting as an important therapy for cognitive decline.

The moral of this relationship between periodic fasting and better cognitive functioning is not that it is needed now to pursue food successfully.  Spending an afternoon observing the legions regularly gorging in fast food establishments would testify to that point.  For most of us we need only to think about the sleepy, foggy brain status after some feasting event such as a thanksgiving meal where we over-indulged.

The current value of periodic fasting is not survival by better food obtainment but rather better brain functioning by its ability to “re-set” metabolic functioning that is so critical for optimal brain health and function.  While ongoing caloric restriction can effectively improve a wide array of chronic health challenges including brain health and cognitive functioning, few will adopt that long-term behavior.  The intermittent modified fasting as described in this series results in much the same long-term benefit but in a much more lifestyle friendly manner for most.