Our brain is constantly eating itself?

Yes, in a very controlled and healthy way — it’s called synaptic pruning and autophagy.

1️⃣ Synaptic Pruning: “Trimming” the brain

• Especially during childhood, adolescence, and sometimes adulthood, the brain removes weak or unused connections between neurons.
• This process is called synaptic pruning — you can think of it like a gardener trimming extra branches.
• It helps the brain become more efficient, improving memory, focus, and cognitive function.
• Without pruning, the brain would get overloaded with useless or redundant information.

2️⃣ Autophagy: The brain’s self-cleaning system

• 
  On a cellular level, autophagy ("self-eating") happens constantly.
• Damaged or old parts of brain cells (proteins, organelles) are broken down and recycled.
• This keeps brain cells healthy and prevents toxic buildup.
• Without autophagy, we would accumulate harmful debris, leading to diseases like Alzheimer's or Parkinson's.

3️⃣ Pathological “eating itself” (when it goes wrong)
 

In some neurodegenerative diseases, these normal processes break down or go into overdrive.

For example:

• Excessive pruning is linked to schizophrenia.
• Impaired autophagy is linked to dementia.
• But under healthy conditions, "self-eating" is necessary and protective.