Healthy Lifestyle Keto There were 211 reports of a total of 46 symptoms that indicated the time of occurrence of keto flu in relation to commencement of KD. These reports were in 56 posts by 56 users and ranged from 1 day to 5 months (median 9.5 days, IQR 5.25–20.25) after commencing KD. All but four of the symptom time course reports were between days 1 and 32, the outliers were single complaints of headache , flu and weak fingernails . The overall pattern of symptom reports between days 1 and 32 is presented in Figure 1. As noted in the method there are spikes at days 7, 14, 21, and 28 where symptoms were reported at week intervals.