You should brush your teeth immediately upon waking before eating or drinking anything, in order to eliminate the bacteria that accumulated during the night and avoid feeding those bacteria with sugars.

noli's read

Bryan Johnson's logic relies on a correct understanding of the oral ecosystem: saliva production decreases during sleep, favoring bacterial proliferation (biofilm). According to the American Dental Association, brushing teeth twice a day is the standard, but the precise timing before or after breakfast remains debated in the literature. Observational studies suggest that waiting 30 to 60 minutes after consuming acidic or sugary foods before brushing is preferable to avoid enamel erosion, as acid temporarily softens the dental surface. Johnson's argument regarding nocturnal proliferation is scientifically grounded (observational evidence on the oral microbiome), but the urgency of brushing *before* any contact with carbohydrates is a highly cautious prevention strategy. There is no rigid consensus (RCT) mandating pre-breakfast brushing as an absolute necessity for everyone, although it helps reduce the initial bacterial load. In short, it is a sound recommendation that maximizes hygiene, without being a universal medical obligation.

the sources

No named source held this one up — that absence is part of the verdict.