cut the power source to ghrelin. But what we do have is the ability to flip the switches (in either direction) through the foods we eat. Those foods, and the chemical reactions they cause when they enter our bloodstream, can increase or decrease the effect of leptin and ghrelin. Fructose, for example, which is found in high-fructose corn syrup and in such devilish products as soft drinks and low-fat salad dressing, can cause your sensors not to receive the leptin message. That’s because many of these processed foods we’re seeing today are imposters; your brain simply doesn’t recognize them as real foods. The effect: As ghrelin goes up or leptin goes down, you reach for a fourth pepperoni stick. But if you eat real foods—like nuts, vegetables, whole grains, and lean animal protein—your brain gives your body a direct order: Let’s close ship, sir, this one’s had enough.
Under normal circumstances, you can keep these hormones in balance and your weight under control by eating minimally processed, nutritious food. But when you’re pregnant, some of your hormones are in hurricane status, affecting your appetite in sometimes unpredictable ways.
Crazy Cravings
You think that your affection for tilapia sundaes is, say, odd? That’s nothing compared to the cravings that some women get. Those who suffer from a condition called pica crave nonfood items such as dirt, clay, freezer frost, paper, paint chips, chalk, sand, soap, and cigarette ashes. That doesn’t mean that they’re crazed; it may mean that they’re suffering from an iron or zinc deficiency. (In some populations, up to 70 percent of pregnant women have pica.) While there are certainly risks associated with consuming some of these items, the biggest problem is that filling up on charcoal doesn’t provide your baby with adequate nutrition. The cravings generally go away with proper iron and zinc supplementation. The other bit of good news: Though it may have an effect on how a waiter looks at you,* pica does not have an effect on baby’s birth weight.
Let’s take cravings, for example, which 75 percent of pregnant women experience. Prior to pregnancy, you may have been a health food fanatic; now you find yourself craving deep-fried onion rings dipped in mayonnaise. Maybe you were a vegetarian; now you have visions of cheeseburgers dancing in your head. Hormones seem to be the most likely source of pregnancy cravings, just as they are for women’s premenstrual cravings of chocolate and carbohydrates (ditto for women who take progesterone for birth control or to relieve menopausal symptoms).
Before you flip off your feminine hormones and blame them for your Almond Joy addiction, consider that a craving is really designed to help you. The scientific speculation is that women crave foods that contain the nutrients they need (like vitamin C or potassium) or simply for calories—both of which may be necessary for fetal development. Makes sense. Our bodies alert us to deficiencies so that we can better protect our offspring or take care of ourselves (so we can better protect our offspring). Consider:
• Women may get cravings for salt because sodium is needed to balance their extra fluid volume during pregnancy.
• Cravings for dry, starchy food during the first trimester may be designed to help relieve nausea.
• Similarly, many cravings may be nature’s way to avert morning sickness, since women are more likely to feel nauseous on an empty stomach.
Appreciating these evolutionary advantages, however, won’t do much to make you feel better if you’re chin deep in a pile of potato chips. Food companies seem to try to seduce all of us to eat too much saturated fat, sugar, and salt. And sometimes we succumb. The trick is to make changes as soon as you realize you have gone off course; it’s not the first cookie that destroys your plans but the ones that follow. Our tips at the end of the chapter will help you keep those cravings in check so that you can do the same with your weight.
The Sick Sense: Nausea and Nutrition
For many women, the big issue about food during pregnancy is what we just talked about: the carte blanche attitude that they’re justified to eat all they want because they’re carrying a baby. But just as many women (and often the very same women) want food about as much as they want a hole in the headboard. They feel sick, get sick, and are sick. And to top it off, they feel guilty about being sick because they worry that they’re not siphoning up enough calories and nutrients for their babies.
The facts about morning sickness* are this: About 80 percent of pregnancies come with a side order of nausea, and 20 percent of women can’t work because the nausea is so bad. Most cases resolve by fourteen weeks, and nausea usually gets better with time (and, typically, with subsequent pregnancies). Plus, it seems that there’s a genetic element to it, since it tends to be passed from mother to daughter.
Holy Molar
Severe nausea isn’t associated with just roller coasters and frat parties. Severe nausea can also be a sign of something called a molar pregnancy. This occurs when those chorionic villi (the coral reefs from the last chapter) swell and keep functioning as if there were a fetus—even when there is no viable fetus. A molar pregnancy, which can spread beyond the uterus like a cancer and also cause heavy bleeding, can be detected by an ultrasound and treated with a small surgical procedure called a D&C (dilation and curettage) to remove the excess tissue from the uterus.
As is the case with most things body related, there may be a very good reason humans developed morning sickness in the first place. During a time when people ate a lot of raw food that could carry bacteria, nausea—which typically occurs in the first trimester, when the baby is most vulnerable—helped the developing fetus avoid exposure to potential toxins, since the mother would likely be able to tolerate the poisoning, while the child might not. If mom was too sick to eat or could stomach only simple, bland food, it reduced the fetus’s chance of being exposed to food-borne illness. Basically, it was better for mom to be nauseous than for the pregnancy to be terminated. Even today, women who experience morning/afternoon/evening sickness are less likely to miscarry than women who do not. It’s a harsh reality, but it’s one of the many ways that our bodies do what we like to call biological budgeting: protecting the life of the baby at the expense of the mother’s comfort.
The true biological reason why pregnant women feel and get sick isn’t fully understood. It seems that something in the vomiting center of the brain (didn’t know you had one, huh?) is stimulated during pregnancy to induce nausea. (See figure 3.3.) In addition, morning sickness may be linked to higher levels of estrogen and/or the high level of the hormone hCG in early pregnancy. Plus, during pregnancy, the digestive tract relaxes, which makes the muscles guarding reflux from your stomach to your esophagus less efficient, causing an increased flow of acid from your stomach into your esophagus. All those factors and the heightened sense of smell you’ll
Figure 3.2 Seeing Sickness If you’re experiencing nausea associated with pregnancy, a couple of things could be happening. The vomiting center in your brain is more sensitive and your digestive tract is more relaxed, making it more likely that foods will travel up as well as down. A number of foods can help you fight through the nausea and give your baby the needed nutrients. Tip: Try cold ones, as opposed to hot foods (hot foods heighten your sense of smell). And hang in there; it usually passes by the end of the first trimester.
Severe Sickness
If you’re unable to keep down liquids for more than twenty-four hours, it may be a sign that you suffer from a condition called hyperemesis (meaning that you vomit a lot). It’s fairly rare (happens in about 1 percent to 3 percent of pregnancies), and some sufferers have to be admitted to the hospital to be rehydrated. Nobody knows the cause, but risk factors include multiple pregnancies,