By Michael Roizen, MD, and Mehmet Oz, MD

There’s a tabloid term - pregorexia – that describes a mother-to-be on a starvation diet. Nicole Kidman (2 kids) and Victoria Beckham (4 kids) are often used as examples of women who preserved their hyper-skinny figures during their pregnancies.  

Now, being too thin while pregnant is bad for mother and fetus, but what we see a lot more of these days are women at the other end of the spectrum: More than 50% of all pregnant women in North America are overweight or obese -- that’s very bad news for a developing fetus. It seems pregnant woman who are obese and eat a high fat diet endanger the development of blood stem cells in the fetal liver and that compromises development of the immune system.The researchers suggest obese-while-pregnant moms may be one reason for the rise in immune diseases and allergies in children.

So if you’re pregnant or planning on it, make the Five Food Felons -- trans and saturated fats, added sugars and syrups, and refined grains -- your sworn enemies. Get daily exercise and gain just enough weight to keep your fetus healthy: less than 15 pounds if you’re obese (BMI>30.0); 15-25 pounds if you’re overweight (BMI 25.0-29.9); and 25-35 pounds if you are a healthy weight (BMI 18.5-24.9). And take a daily prenatal vitamin with DHA for three months before trying to conceive, right through delivery and breastfeeding. That decreases childhood cancers by 65%, birth defects by 80%, and autism and autistic spectrum disorders by 40%.