So this one takes some extra Internet sleuthing. They helpfully mention the rubs for each entree item, and they sell their rubs on Amazon. Best of all, they have photos of the front and back for the rubs, meaning they have a photo of the ingredients for the rubs!

You just need really good eyes to read them, cuz the photos are small. :|

Brisket rub (https://www.amazon.com/4R-4-Rivers-Rub-Brisket/dp/B074HD9KRB/ref=sr_1_1?ie=UTF8&qid=1600465439&sr=8-1&keywords=4+rivers+bbq): salt, spices & coloring, garlic, onion, silicon dioxide. No sugar! I doubt they'd use the silicon dioxide in the rub they use in the restaurant, so I'd probably be ok with that.

All-purpose rub (https://www.amazon.com/4-Rivers-Rub-All-Purpose/dp/B074HC4DMJ/ref=sr_1_1?ie=UTF8&qid=1600465786&sr=8-1&keywords=4+rivers): salt, sugar... I'm gonna stop there. They use their all-purpose rub on pulled pork, pulled chicken, St Louis Ribs, and smoked chicken.

Keep in mind that most sausages have sugar in them, so I'd skip hot links or sausages too.

I didn't look at the sides, but most BBQ sides have either sugar or dairy.

I'd grab a salad from the store to get your veggies in, and either an avocado or some olives for your fat. If they did order the brisket, there's your protein! But I wouldn't risk anything else.

Good luck!