Each absorption scheme consists of three parameters:
- Delay: The time required by your body to digest the respective carbs, i.e. after this time period they will impact your blood glucose.
- Absorption time: The time how long these carbs will - once started - impact your blood glucose (this parameter can be entered for sugars and regular carbs only, for e-carbs it will be calculated).
- Interval: This parameter is only required for exporting the carbs to Apple Health. The total amount of the respective carbs will be evenly distributed over the time period determined by the absorption time parameter, using this interval. Example: Given a 3h (=180min) absorption time and a 10min interval, an amount of 36g will be distributed in 18 chunks, 2g each: 36g / (180min / 10 min).
Absorption Scheme for Sugars
You can choose whether or not to treat sugars separately from regular carbs. If you choose not to, sugars will be accounted for as regular carbs.
Sugars are usually absorbed within a relatively short period of time. Default setting is 2 hours with a delay of 0.
Absorption Scheme for Regular Carbs
If you have chosen to treat sugars separately, they will be substracted from the regular carbs.
Regular carbs are usually absorbed slower than sugars. Default setting is 3 hours, starting with a delay of 5 minutes.
Absorption Scheme for Extended Carbs
Extended carbs are not really carbs, but rather Fat-Protein-Units (FPUs), but they impact blood glucose just as if they were. As they stem from fat and proteins, which first need to be digested by your body, they will impact your blood glucose rather late (default setting is after 90 minutes).
The duration of impact is determined by the following absorption scheme, which matches today‘s recommendations from nutrition science:
- 1 FPU: 3 hours absorption time
- 2 FPUs: 4 hours absorption time
- 3 FPUs: 5 hours absorption time
- 4 FPUs: 6 hours absorption time
- 6 FPUs and more: 8 hours absorption time
This absorption scheme may also be modified.
By default, 1 FPU has a blood glucose impact comparable to 10g of carbs. This ratio can (and should!) be modified, as it is very individual. Especially for children it's recommended to start with a much lower carbs-per-FPU-ratio, e.g. 4 or 5 g/FPU.
The calculation algorithm for the FPU and e-carbs is as follows:
Step 1: Calculation of the total calories, e.g. for 72g Chicken McNuggets (249 kcal per 100g): 72g * 249 kcal / 100g = 179 kcal
Step 2: Calculation of the calories caused by carbs (4 kcal per 1g of carbs), e.g. for 72g Chicken McNuggets (17g carbs per 100g): 72g * 17gCarbs / 100g * 4 kcal/gCarbs = 49 kcal
Step 3: Substract the calories caused by carbs from the total calories, e.g.: 179 kcal - 49 kcal = 130 kcal
Step 4: As 100 kcal represent 1 FPU, this results in 1.3 FPUs, which could for example be 13 g e-carbs if the carbs-per-FPU-ratio was set to 10 g/FPU.
Step 5: The FPUs will be rounded, in our example to 1 FPU, and the absorption time will be looked up, in our example 3 hours.
Editing the absorption schemes is only recommended for advanced users, who have experience in FPUs / absorption time. All absorption schemes can always be reset to the pre-defined values.
Alert Period between Apple Health Exports
In order to avoid double exports by mistake (potentially increasing the insulin delivery of your Loop system), EasyFPU will warn you in case you export data withing a given period of time after the last export. This time period can be set here. Default is 15 minutes.