I wouldn't advise it during Attack, weegie. Try and keep everything as pure as possible. Attack doesn't last for long and it's worth doing it right.
Even when you get onto Cruise, be careful and treat them as tolerated items - only a little (maybe a tsp of soy sauce, for example) per day. I think that you're allowed 2 tolerated items per day from Cruise onwards. Most people experience faster results if they use as few tolerateds as possible.
Be careful with the Five Spice powder as it often contains sugar. I believe that some people have had success in mixing up their own versions - try some ground star anise, cinnamon, etc and I bet that you could come up with a lovely, much more Dukan-friendly version.