Titsalina - gravy granules or flour really aren't OK on Bootcamp.
For example, a 50ml serving of Bisto gravy granules (red tub) will add 2g carbs to your meal. I know that doesn't sound very much - but actually 50ml isn't much either, if you're a gravy fiend!
More pertinently though, these are the ingredients:
Potato Starch, Maltodextrin, Palm Oil, Salt, Wheat Flour (with added Calcium, Iron, Niacin, Thiamin), Colour (E150c), Sugar, Flavourings (contain Barley), Flavour Enhancers (E621, E635), Emulsifier (E322) (contains Soya)
Not exactly fresh, natural or unprocessed - which is what we're aiming for on Bootcamp.
Best bet is to make your own. Have it unthickened, or add some veg to the roasting tin when you're roasting your meat and then mash the veg into the liquid to thicken it.