Zero-carb is not a good idea, and in fact is almost impossible for very long, as the number of foods that contain no carbohydrate at all is quite small.
Iíve spent quite a lot of time designing low-carb menus that have all the essential nutrients in them. Although it is possible at 20 grams of net carbs, it is not at all easy. Just adding 10 or 15 more grams makes it much more attainable. If you want to make it easy, go to 40-50 grams per day, which means you can also get a wider variety of phytonutrients as well. I realize that there are some people who are extremely sensitive to carbohydrate and cannot tolerate this much, but in my experience most people can, especially if most of the carbohydrate comes from non-starchy vegetables. (For example, spinach and other greens have carbs, but they are so wrapped up in fiber that most people will not experience a blood glucose impact at normal amounts.)
To eat zero carbs is to seriously restrict the range of nutrients you can eat, and not a good idea.
To read what other authors and researchers had to say on the subject, check out Jimmy's blog post on zero-carb eating.
Photo © Karen Struthers