I mean EU in the widest sense including us, the EU citizens, including personal trainers and marketing people.

By more understandable you mean they’re used to. They can get used to something else.

I’m not forcing anyone, I’m trying to influence them to use joules instead

From Wikipedia:

However, the calorie is not part of the International System of Units (SI), and is regarded as obsolete,[2] having been replaced by the SI derived unit of energy, the joule (J),[9] or the kilojoule (kJ) for 1000 joules.

Can’t really compare but Silampos have a great reputation in Portugal: https://www.silampos.pt/pt/

The shop link: https://www.silampos2.pt/en/