Mixed
For deaths related to mental/behavioral disorders, neurological conditions, and non-transport accidents, lower BMI (up to 24-27 kg/m²) is associated with increased mortality risk, showing an inverse linear association rather than a J-shape.
Don't assume being thin is always safer. For neurological and mental health-related causes of death, this study found that lower BMI (down to 24-27) was associated with higher risk. Maintaining a healthy weight (not underweight) is important for protecting against these specific outcomes.
For mental and behavioural, neurological, and accidental (non-transport-related) causes, BMI was inversely associated with mortality up to 24–27 kg/m², with little association at higher BMIs; for deaths from self-harm or interpersonal violence, an inverse linear association was observed.
Why this rating
Large cohort size and rigorous exclusion of smokers and early follow-up reduce confounding, making the inverse association for these specific causes highly reliable.
Source
Association of BMI with overall and cause-specific mortality: a population-based cohort study of 3·6 million adults in the UK
Krishnan Bhaskaran et al. · The Lancet Diabetes & Endocrinology · 2018
DOI 10.1016/s2213-8587(18)30288-2
Related findings · Mixed
- Bariatric surgery (VSG and RYGB) is the most effective and sustainable treatment for obesity, producing marked and sustained weight loss that non-surgical interventions cannot match.Strong
- Severely protein-deficient diets (2–3% energy) induce lean body mass loss and metabolic imbalance, whereas adequate protein intake (0.66 g/kg/d minimum) is a prerequisite for maintaining muscle, bone, and physiological function.Strong
- For patients with Class III obesity (BMI >39.9 kg/m2), metabolic bariatric surgery (MBS) is significantly more effective than any currently approved medication, with BilioPancreatic Diversion (BPD) showing the highest estimated weight loss.Strong
This is one finding among thousands. Every one is graded and traced to its source, so you can see what the evidence actually supports. Browse the research →