For every 5 points your BMI goes up, your risk of dementia jumps by 63%. But it's NOT the fat destroying your brain — it's your blood pressure. A massive 500,000-person study using Mendelian randomization just proved the causal link.Topics covered:- Why blood pressure mediates 25% of obesity's effect on dementia- The 156% and 232% risk increases from hypertension- 4 mechanisms: vascular damage, chronic inflammation, insulin resistance, brain shrinkage- Why the obesity paradox is a statistical mirage- Exercise, heat therapy, sleep, and diet interventions that workSource: JCEM 2026 Mendelian randomization study via FoundMyFitness