Pregnancy and Diet
That said, a woman can still occur without risk factor for gestational diabetes. This awareness of your diet is to their credit, as it is important for you and your baby, regardless of the test result.
No diet during pregnancy
To answer your question, strongly follow any type of diet during pregnancy because of the physical changes that you are living increase in their nutrient and energy needs is recommended.
The books you mention are designed in order to lose weight, so it is not at all adapted to the needs of pregnant women.
A balanced diet
I suggest you eat foods that are in the 4 groups of Canada's Food Guide every day. Your baby needs you to feed, so it is very important to eat the right amounts for your condition. You can find more details on the website of Canada's Food Guide.
Pay special attention to your diet and keep doing physical activity, which is a great initiative.
Gestational diabetes
If your doctor makes a diagnosis of gestational diabetes or glucose intolerance, a special and explain recommended by a nutritionist or health professional diet because this diet is different from what is usually recommended for diabetics. In fact, pregnant women need a greater amount of nutrients to promote optimal growth of your baby.