Hi Pogie!

It may not be the gum causing your slow results. Many people find that their second, third, etc...attempts at low carbing after being off it and regaining result in much slower weight loss than the first time. Be patient and stick with it. OTOH, if you're chewing 20-30 pieces a day, that can add up at roughly 1 gram of carb per piece so take that into consideration as well.
With nicotine gum, you're not supposed to chew it like you would regular gum (continuously); you're supposed to give it a couple of chews and then park it between your cheek and gum for a while until you stop tasting the gum, then repeat:

How To Properly Use Nicotine Gum

1 - Start slowly by chewing once or twice to see if you can taste the gum. If not then continue to slowly chew until you taste the gum.

2 - Once you taste the gum place it between your cheek and your gum line. After the taste begins to dissipate chew it again. Once the taste returns place it back into its spot between your cheek and gum line. Repeat this process once every minute or two minutes. The normal cycle should continue for between twenty to thirty minutes at which time it should be thrown away. Remember to avoid drinking any liquids while chewing the gum.

http://ezinearticles.com/?The-Prope...oking&id=891170