Molly has food intolerances too and is only able to eat salmon and potatoe food. She was also very skinny and is quite tall and weighed 10.3kg. My vet suggested adding coconut oil to her food and it seems to have worked. We tryed all different tablets and potions,but this seems to work, she is now 12.65kg, it has taken about 8-10 months though. For dogs without food intolerances Frolic seems to put the weight on them really quickly.