Several low carb proponents including authors suggest a FAT FAST to break a plateau. A Fat Fast is simply a 5 day "fasting" where you eat very little food in the form of 5 servings of fat per day for those 5 days. It's a combination of almost zero carb coupled with a fast.
Here's an example of what an entire days food would consist of;
3 strips of bacon
2 ounces of cheese
2 ounces of macadamia nuts
2 ounces of soy nut butter
1/2 avocado
As you can see the "fasting" is obvious, so little food is being taken in during a full day and all of it high fat low carb.
Yes, doing a Fat Fast for 5 days will certainly force your body into ketosis and you will
lose weight during your Fat Fast. You'll also learn during this week how little food your body really needs.
Personally I never suggest "fasting" to anyone, its simply to dramatic on the system. You can expect side affects such as being moody, light headed and a loss of concentration. If this is something you feel you will try I suggest you consult your doctor first.
My suggestion to breaking a plateau is very simple, reduce those carbs to under 10 per day and cut your portions in half. Only eat when you are truly hungry and wait 15 minutes before touching the other half of the portion. If you find yourself satisfied then wrap up the other half and put it away. If you're still hungry eat a bit more.
This method will work every bit as well as a Fat Fast without the "fasting" part of the exercise. It is also a sustainable method witch can go on for months without affecting your body in a negative way.