Fasting Readiness appears on the Body Insights Today's Readiness card. It uses your available sleep and glucose data. The result helps you decide whether to fast or eat breakfast.
What does Fasting Readiness show?
The card shows one of four recommendations:
Good Day for Fasting
when the available data supports fasting
Eat Breakfast Today
when the available data weighs against fasting
Flexible Today
when the result sits between those two choices
Unable to Assess
when there is not enough supported data
The percentage beside the recommendation is the app's confidence in that result. The card also lists up to three reasons.
How should you use Fasting Readiness?
Check the card before breakfast, then read it in this order:
- Start with the recommendation.
- Check the confidence percentage.
- Read the reason lines to see what shaped the result.
Example: after a rough night
After a very short, broken night, Body Insights reads the sleep record from Apple Health. The card may show Eat Breakfast Today. Its reason lines may include Very short sleep, Fragmented sleep, and Sleep debt accumulated.
Eat breakfast that morning. Check the card again after your next full night of sleep. Mixed inputs on another morning may give you Flexible Today.
What builds the recommendation?
Body Insights uses the sleep and glucose data that is available that morning.
Sleep
Your Apple Watch records sleep data. Body Insights uses those records from Apple Health to calculate sleep duration and efficiency. It also compares your sleep duration with your target.
Glucose
A compatible continuous glucose monitor measures glucose and shares it through Apple Health. Body Insights checks your current reading against your recent glucose pattern. It also checks how stable your glucose has been.
What happens when data is missing?
When glucose data is missing, the calculation leaves it out. If sleep data is available, the app can still calculate a result from sleep alone.
If there is not enough data to calculate a result, the card shows Unable to Assess. Its reason line asks you to eat normally that day.
Check today's fasting readiness
See your recommendation, confidence, and the main reasons behind it.
See my fasting readiness