My ketone levels dropped suddenly — did I do something wrong?

Blood ketones fluctuate normally throughout the day and between days — this is physiology, not failure. Your 0.3 reading doesn't mean you left ketosis or did something wrong. Here's what causes day-to-day variation:

1. Time of measurement: Ketones are typically lowest in the morning (your body uses them overnight) and highest 2-4 hours after a fat-rich meal. Morning tests often show lower numbers than afternoon tests.

2. Exercise: During intense exercise, muscles consume ketones rapidly. Blood ketone levels drop during and after exercise even while remaining in nutritional ketosis.

3. Stress: Cortisol triggers gluconeogenesis, slightly raising blood glucose and relatively lowering ketone ratios.
4. Sleep quality: Poor sleep raises cortisol, similar effect to stress above.

0.3 at one morning reading from a usual 1.5-2.0 range is absolutely normal variation. Don't panic. Test again 2 hours after a fatty meal and you'll likely see 1.0+ again.

Testing daily gives you data but also noise that causes unnecessary anxiety. Most experienced keto practitioners test a few times per week at most — same time, same conditions for meaningful comparison. Daily testing will show you variations that are normal but look alarming without the context of many data points.

I tested daily for 3 months and it made me neurotic. Now I test Monday mornings, fasted, same time. That gives me a consistent comparable data point without the noise of hourly and daily variation. My stress about keto dropped dramatically with this change.