Coffee (3-4 cups/day)
BMJ umbrella review: 3-4 cups/day associated with lowest all-cause and cardiovascular mortality.
Why
Poole et al. 2017 BMJ umbrella review synthesised 201 observational meta-analyses and 17 trial meta-analyses. Three to four cups per day was associated with the largest relative risk reduction across all-cause mortality, cardiovascular mortality, and CVD incidence. Decaffeinated coffee shows similar (though smaller) effects. Beneficial effects are dose-response up to ~4 cups; harms emerge mostly at higher intakes or in pregnancy.
How to do it
How
Black, no/low sugar. Spread across the morning. Last cup by ~2pm to protect sleep (caffeine half-life is 5-7 hours).
Ideal for
Adults already drinking coffee or considering it; not a recommendation to start drinking coffee if you don't want to.
Markers this may influence
Evidence
Poole 2017 BMJ umbrella review (201 meta-analyses of observational research): 3–4 cups/day showed the largest relative-risk reductions, RR 0.83 for all-cause mortality, RR 0.81 for cardiovascular mortality, RR 0.85 for cardiovascular disease incidence vs non-drinkers. Benefits plateau or attenuate above 4 cups; harms emerge mostly at higher intakes or in pregnancy.