If you’re an avid follower of the research into improving brain health, you’ve probably heard about the benefits of fasting or near-fasting – when you eat a very limited amount of food during a 24-hour period. “Near-fasting” is more commonly called “intermittent fasting.”

If you haven’t heard about fasting, then it’s time you did! Simply doing without food – or getting by with drastically less – is now known to be a secret of youth. And that includes a youthful brain.

As I’ve reported before, research shows that fasting increases the number of stem cells in the brain that can help regenerate neurons.1

Now, added to that, researchers at Harvard have been busy looking into how you can add more oomph to your fasting so that your brain reaps greater benefits. . .

The researchers say their work points to a method that eliminates more toxins from brain cells.

To understand the Harvard research, think of brain cells as protein factories – constantly assembling and folding complicated proteins that enable cells to function and communicate with other cells.

Like any factory, cells can make mistakes, producing proteins shaped to the wrong template or manufacturing an oversupply of a particular protein. Those mistakes have to be disposed of or recycled.

When the Harvard scientists took a close look at the “quality control” cellular maintenance program that allows each cell to clear its factory floor, they found that fasting or intermittent fasting – where you may take a day off every month or so without eating (or eating very little on that day) – makes the cellular cleanup processes more efficient.

Do This to Boost the Benefit of Fasting

And a key extra ingredient for cell cleanliness? Exercise. Physical movement, even if it is just brisk walking, can “turn up the cellular vacuum cleaner,” according to researcher Alfred Goldberg, who teaches cellular biology at Harvard.2

That’s a big help to cells – because when a cell’s cleanup program slows, improperly folded proteins can clog up each cell’s machinery. As those junk heaps of useless proteins in nerve cells reach a tipping point, say the researchers, it can lead to neurodegenerative illnesses like ALS (amyotrophic lateral sclerosis) and Alzheimer’s disease.

I won’t go into all the specifics that the Harvard scientists describe, but they found that the cell’s “vacuum cleaners”  get high powered with fasting and exercise because they –

  • Switch on a messenger signal called cAMP, activating an enzyme named protein kinase A – which leads to the elimination of toxic proteins that can cause neurons to be destroyed.
  • Stimulate the action of proteasome, a substance that reacts with defective proteins, tearing them apart so that cells can recycle their component amino acids.

Fasting and Exercise Support Mitochondria

Another avenue through which fasting and exercise help the brain is through improvements in the way mitochondria function in neurons. As long-time readers know, mitochondria are the “batteries” of a cell.

Tests in Brazil show that fasting increases the amount of calcium that the mitochondria in neurons can hold on to.3 By collecting extra calcium, the mitochondria can protect neurons from being damaged by what’s called excitotoxicity – a destructive reaction to the neurotransmitter glutamate.

When a neuron over-reacts to glutamate, it resembles what happens to your TV set when lightning hits your house. A lightning voltage surge can cause TV circuits to be overloaded and fried, destroying your TV set. In the brain, excitotoxicity does something like that – overwhelming and burning up neurons.

But extra calcium in mitochondria is like a surge protector that keeps the overload from putting neurons out of commission.

Plus, an additional benefit to intermittent fasting is that it makes mitochondria more adaptable in the way they react to available nutrients in the cell – switching from processing sugars to fats. Tests show fasting helps them metabolize fat more effectively.4

Of course, all of these benefits don’t just happen in brain cells. They’re widespread in the body. That’s a key reason researchers keep doing detailed tests on fasting and exercise. Together they’re becoming the dynamic duo of preventive medicine.

All-out fasting is a challenge for most of us, which is why intermittent fasting has become so popular. The easiest approach is to make sure at least 12 hours pass between your last meal of the day and your first meal in the morning.  Much more effective is to wait 16 hours between the first and last – meaning you do all your eating during an eight-hour window – perhaps from 10 AM to 6 PM.


  1. http://www.cell.com/cell-metabolism/abstract/S1550-4131(15)00224-7
  2. https://www.ncbi.nlm.nih.gov/pubmed/30782827
  3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5242290/
  4. https://www.ncbi.nlm.nih.gov/pubmed/29107506