Sugar substitutes are popular, especially xylitol (birch sugar). Xylitol is tooth-friendly, hardly affects blood sugar and is low in calories. For dogs it is life-threatening, even in very small quantities!
Are you visiting with your dog and are having cake or biscuits? Ask whether xylitol (birch sugar) has been used. If so, make everyone present aware of the high risk and don't let your dog out of your sight.
If it does happen: call the vet immediately and discuss the next steps. Do not wait until the dog shows symptoms! The more severe the symptoms, the worse the prognosis.
Caution: Xylitol is found in toothpaste and in an increasing number of sweets and other foods. Don't feed your dog anything made for humans without knowing the ingredients for sure!
More on this topic:
https://www.gesundheitszentrum-fuer-kleintiere-luedinghausen.de/tierarztblog/artikel/xylit-hund.html