jones_supa writes Being overweight cuts the risk of dementia, according to the largest and most precise investigation into the relationship (abstract). The researchers were surprised by the findings, which run contrary to current health advice. The team at Oxon Epidemiology and the London School of Hygiene and Tropical Medicine analyzed medical records from 2 million people aged 55 on average, for up to two decades. Their most conservative analysis showed underweight people had a 39% greater risk of dementia compared with being a normal healthy weight. But those who were overweight had an 18% reduction in dementia, and the figure was 24% reduction for the obese. Any explanation for the protective effect is distinctly lacking. There are some ideas that vitamin D and E deficiencies contribute to dementia and they may be less common in those eating more. Be it any way, let's still not forget that heart disease, stroke, diabetes, some cancers and other diseases are all linked to a bigger waistline. Maybe being slightly overweight is the optimum to strike, if the recent study is to be followed.