The document lists 10 biggest brain damaging habits: 1) Not eating breakfast lowers blood sugar and deprives the brain of nutrients. 2) Overeating causes hardening of brain arteries and decreased mental power. 3) Smoking causes brain shrinkage and may lead to Alzheimer's. 4) High sugar intake interrupts nutrient absorption and brain development. 5) Air pollution decreases oxygen to the brain, lowering efficiency. 6) Sleep deprivation accelerates brain cell death. 7) Sleeping with your head covered increases carbon dioxide and lowers oxygen to the brain. 8) Working or studying while sick can lower brain effectiveness and damage the brain. 9) Lacking stimulating thoughts may cause brain shrinkage. 10) Talking rarely versus intellectual conversation