I have Riley (5 years old neutered male) who keeps losing weight. He does take Soloxine twice daily, but has been monitored and the level is fine (just last week). He had a complete urineanalysis and blood work and everything came back normal. He eats 3.5 cups per day of Natures Variety Instinct grain free salmon dry food and a whole can of Addiction Rabbit and Blueberries dog food. He still loses weight (just a pound or two a month). Does anyone have any ideas? This has been happening over the last 3-4 months. He had been checked for internal parasites (fecal) and nothing was found. It almost seems like the food is just going in one end and out the other. Thanks for any insight anyone can share.