Carrying the Weight | by Lisa Marshall

Posted on Thu, Jun 5, 2014

For moms-to-be, what they eat, gain can set baby up for life of obesity, disease

“Dig in! You’re eating for two.” For decades, well-meaning loved ones have offered up such advice to moms-to-be, urging them to go easy on exercise and load up on calories to grow a “strong, healthy baby.” But at a time when half of pregnant women are overweight when they conceive, one in 10 are obese, and 40 percent of those who start out lean gain more than recommended, many physicians are challenging the conventional “more-is-better” wisdom, saying women should keep their weight gain in check, particularly given new knowledge of the potential long-term health effects on their child.

“We are learning that the obesity and diabetes epidemic actually begins in utero,” says Dr. James Wilk, an internal medicine physician who specializes in high-risk obstetrics at Rose Medical Center.

Researchers have long known that overweight pregnant women are more likely to suffer complications, such as gestational diabetes, high blood pressure, pre-term or prolonged labor, and emergency C-section. But new research suggests the consequences of excess maternal weight gain and “over-nutrition” during pregnancy can extend far beyond delivery day for babies, impacting their body-fat composition, appetite, and metabolism for years to come, says Dr. Linda Barbour, a researcher and professor of obstetrics at the University of Colorado School of Medicine.

“We know that the children of women who are overweight or obese have a 2.5- to four-times greater risk of becoming obese as young adults,” says Barbour. “We are learning there are a number of different factors that play into that risk.”

Big mom, big baby, big teenager

Two critical factors are weight and fat composition at birth. One 2011 study found that the children of women who gained more than 40 pounds during pregnancy were twice as likely to be oversized at birth, and as much as four times more likely to be overweight at age 5. Another 2013 study followed 1,000 Australian girls from birth to 17 and found that those who were heavier at birth were twice as likely to have a large waist circumference, higher levels of insulin and triglycerides, and lower levels of good cholesterol as teens. Roughly 9.5 percent of babies are now “large for gestational age” (more than 8 pounds 14 ounces).

“When babies are born big, these babies have a higher risk of developing not only obesity, but also diabetes and high blood pressure into adulthood,” Wilk says.

Poor diet, not just weight gain in mom or baby, also fuels problems, Barbour says. Normal-weight moms who eat too much sugar while pregnant can have babies with bigger pancreases that produce too much insulin, resulting in low blood sugar in infancy and possibly diabetes later in life, as those overstressed pancreatic cells fatigue. Moreover, moms who eat too much fat (particularly saturated fat) during pregnancy tend to have babies with a greater percentage of fat cells when they’re born (even if they are of normal weight), which they can carry with them later in life.

An intrauterine environment oversaturated with fat, sugar, and excess calories may also influence hormones that control appetite regulation in babies’ brains, and turn off or on genes that influence mitochondrial efficiency (how food is burned for energy during exercise), says Barbour. Some animal studies also suggest that when a pregnant mom is obese or overweight, she passes a fat-prone “microbiota” or collection of gut bacteria, on to her baby.

The good news: Knowledge is power, says Barbour. “It’s an exciting time. We are starting to realize the power of the intrauterine environment as a platform for women to do something to improve their babies’ long-term health.”

Here’s what moms can do to get baby off to the best start possible:

Skinny jeans first: If possible, try to slim down to a healthy weight prior to getting pregnant, says Denver OB/GYN Kristine Eule. “If you are coming back for a second or third pregnancy, and you haven’t lost the weight from before, wait until you have.” Eule recalls a patient who started out at 110 pounds with her first pregnancy, gained 40 pounds, and got pregnant again before losing the excess weight. Now she’s on her fourth pregnancy at 260 pounds. “Ideally, if someone is thinking about getting pregnant, we try to have them come in for preconception counseling, work on diet, and get in the best shape they can be going into it.”

No ticket for two: “The eating-for-two advice is a complete myth,” says Dr. Heather Fitzler, an OB/GYN with the Center for Women’s Health in South Denver. In reality, she says, your caloric intake doesn’t need to change at all in the first trimester. In the second and third, on average, it should increase by about 300 calories, the equivalent of one whole-wheat bagel.

The scale rules: According to the Institute of Medicine’s revised 2009 guidelines, underweight women (with a Body Mass Index of 12.5 to 18) should gain 28 to 40 pounds; women of normal weight (BMI of 18.5 to 24.9) should gain 25 to 35 pounds; overweight women (BMI of 25 to 29.9) should gain 15 to 25 pounds; and obese women (BMI of 30-plus) should gain 11 to 20 pounds. However, many physicians – including Wilk and Barbour – believe these guidelines are too generous. “In some overweight and obese women, the babies do just fine if the mom gains zero,” says Wilk.

Bye-bye sugar: “Pregnant women are warned about all kinds of things they shouldn’t eat because of the health risks, but sugar is probably the number-one worst thing she can put in her body,” says Wilk. He notes that simple sugars, like those found in soda, juices, candy, etc., fail to trigger the hormones that tell the brain “I am full,” so despite the calories they pile on, they leave us hungry. The same goes for refined carbohydrates, like white rice. Instead, shoot for low-glycemic-index carbohydrates, which leave blood sugar on a more even keel, and fiber-containing fruits and vegetables, which fill you up. Have an orange instead of orange juice. Substitute quinoa for white rice.

Easy does it: While moms with gestational diabetes have long been told to steer clear of sugar, some experts fear that they might be replacing it with excess fat, which has its own serious drawbacks, says Barbour. One recent CU study conducted on primates found that those who ate a high-calorie, high-fat (35 percent) diet during pregnancy (regardless of whether they were overweight or not) produced fetuses with fatty-liver disease and babies with far more fat cells.

A healthy plate: Wilk advises pregnant moms to divide their plate in half and load one half up with as many vegetables as possible (French Fries don’t count). Then divide the other half in two, putting lean protein in one quarter and low-glycemic index carbohydrates like whole grains in the other quarter. Have two servings of fruit per day as snacks and a healthy snack with protein (like hummus and veggies) before bedtime. “The bed time snack, paradoxically, lowers blood sugar in the morning,” he says.

Get moving: “It is a common fear that pregnant women have – that if they do vigorous exercise it will be bad for baby,” says Fitzler. “But in reality, nothing so far has shown that exercise is detrimental.” While doctors used to warn that excess exercise could shunt blood flow away from the placenta, more recent studies suggest exercise actually builds a stronger placenta. Fitzler recommends pregnant moms get at least 150 minutes of moderate-intensity exercise per week (unless complications prevent it). Just be sure to drink lots of water and back off if you feel yourself overheating or your heart is beating too fast.

Never too late: What if you’re in your third trimester, and you’ve already gained more than you should? No problem, says Wilk. “Start eating healthy now and start going for walks. Say you have gained 40 pounds already, and you gain nothing else. That’s OK,” he says. “The good news is that in the later stage of pregnancy is when interventions have the most effect.”

Tags: healthy pregnancy, nutrition, OB/GYN