I dont think they will, as its only flavourings and gelatine at the end of the day....
Heres a typical nutritional and ingriedients section on a Hartleys sugar free strawberry jelly.
Ingredients:
Gelatine, Acidity Regulator (E331), Citric Acid, Flavouring, Sweeteners (Aspartame, Acesulfame K), Strawberry Juice (1%), Maltodextrin, Colour: Ponceau 4r.
Contains a Source of Phenylalanine.
Allergies information:
Contains Maltodextrin & Phenylalanine
Nutrition:
Nutrient per 100g (as sold) per 140ml (1/4 pt)
Energy kCal 280kCal 8kCal
Energy kJ 1,188kJ 34kJ
Protein 56.8g 1.6g
Carbohydrate 13.1g 0.5g
Fat Trace Trace
I done them and was fine.