Registering new food without its weight/volume

I use this app daily in Japan to record my meals, exercise, and body measurements.
I would like to share some issues regarding the registration of new food items and provide suggestions for improvement.
When registering food items with barcodes, it is currently only possible to register nutritional information in units of “100g” or “100ml.”
However, in Japan, the nutritional information on product packaging is often displayed not only per 100g/100ml but also for the product itself.
This is sometimes because the package represents a single serving, which means that the weight of the product is often different from 100g/100ml.
Since our primary interest lies in the energy contained in the consumed food, we believe it should be possible to register food items without requiring input of weight or volume.