Eating like our Ancestors 

June 20, 2024

‘Our typical eating pattern of three meals a day plus snacks flies in the face of our evolutionary history. Over 1.5 million years of eating sporadically, our brains evolved in response to what we might call ‘intermittent fasting’. – Professor James Goodwin

Intermittent fasting is not novel. Its roots date back to ancient times when our ancestors first experienced periods of feast and famine between hunting trips. In the early 20th century however, scientists began exploring the physiological effects of fasting. It is thought that the episodic food shortages not only help to develop a brain whose activities are sharpened when hungry or even starved, but that the benefits could improve overall health and even extend lifespan. 

At rest, we deplete the energy supplies of our liver in about 12 hours of non-eating. Extend this to 24 or even 48 hours and the brain has no glucose left, its main source of energy. At this stage, we begin to access and run on ketones, a type of chemical that the liver produces when it breaks down fat. This end result is called ‘ketogenesis’. Ketones is the evolutionary alternative energy supply to glucose. However, due to food being easily accessible in the western world, we often deny it to the brain. 

So, what are the brain health benefits of intermittent fasting and is it something we should be putting into practice? 

  1. Enhancing brain function: intermittent fasting triggers various cellular processes such as the production of neurotrophic factors including BDNF that promotes the growth of brain cells in the hippocampus. It can be said that intermittent fasting has the power to enhance and protect against neurodegenerative diseases and prevent cognitive decline.
  2. Boosting memory and encouraging neuroplasticity: intermittent fasting can enhance synaptic plasticity, forming new neural pathways and connections. This is crucial for keeping the mind active, learning and forming new memories.
  3. Reducing neuroinflammation: in today’s fast paced life, chronic inflammation and stress is a contributing factor to many diseases including brain disorders such as dementia and Alzheimer’s disease. Intermittent fasting is said to reduce inflammation markers in the brain, lowering the risk of cognitive decline as we age. 
  4. Boosting mitochondrial health: mitochondria (tiny structures in our cells) are known as the ‘powerhouse of the cell’ and work by breaking down food molecules into ATP (Adenosine triphosphate) which gives each cell the energy it needs. Intermittent fasting induces a process called ‘autophagy’, which is a cleaning process ridding each cell of components that no longer work, including the removal of dysfunctional mitochondria. This helps protect the cell from oxidative stress and age-related decline. 

One study published in the New England Journal of Medicine in 2019, found intermittent fasting to have a positive effect in several neurological conditions including Parkinson’s and Alzheimer’s disease, although it’s important to note that many studies they reviewed involved animals only. Today, we still await direct evidence from large-scale clinical trials, but the practice of intermittent fasting has certainly surged in popularity due to its positive link to brain health and physical health. 

Intermittent fasting isn’t difficult or tedious to do.  There are different eating patterns by which it can be done but the easiest is the ‘overnight’ method when of course we are asleep.  Simply finish eating by 7pm then fast overnight.  Time breakfast for 12 or even 14 hours later (ie between 7 and 9 am) by which time your brain will be working on ketones!  Remember, ALWAYS talk to your doctor before embarking on any kind of fasting.

Read more on ‘eating like our ancestors’ in Supercharge your Brain, written by Professor James Goodwin.