Typically you want to stay away from any brands that use filler ingredients like maltodextrin and dextrose, or high glycemic sweeteners like maltitol. Many low-carb products that claim low net carbs usually use these sugar alcohols. Many candies that are “sugar-free” also use these sweeteners. Avoid them where possible. These specific sweeteners respond in our body in a similar way sugar does.
If you choose to make your sauces and gravies, you should consider investing in guar or xanthan gum. It’s a thickener that’s well known in modern cooking techniques and lends a hand to low carb by thickening otherwise watery sauces. Luckily there are many sauces to choose from that are high fat and low carb. If you’re in need of a sauce then consider making a beurre blanc, hollandaise or simply brown butter to top meats with.