While satisfying your cheese-fry craving is sometimes 100% necessary in pregnancy, you may want to switch it up with a green salad (if you can stomach it), since a 2015 study found that pregnant women who keep high-fat, calorie-dense diets while carrying can pass on a whole slew of health issues to their children.
The research, which was carried out by a group of doctors from The Cleveland Clinic and West Virginia University, studied the repercussions of a mother's diet on the child's chances of developing asthma and abnormalities of lipid and glucose metabolism.
"If we want to influence the development of things like asthma, diabetes and obesity, we have to intervene either during pregnancy or in the very first months of life with the child," said Giovanni Piedimonte, M.D., institute chair for the Center of Pediatric Pulmonary Medicine at the Cleveland Clinic. "Any diet that is not correctly balanced with the content of carbohydrates, protein and lipids may have consequences on the fetus. It is [also] very important to realize that vitamins are essential."
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The researchers observed mice for the purpose of this study (as it would be unethical to involve humans) and only altered their diets during pregnancy.
"The only change was the content of fat and lipids during pregnancy exclusively and just that was able to significantly modify the structure of the lungs," Dr. Piedimonte explained. "The airways became very reactive and with the babies that were from mothers that were fed the high-fat, high-caloric diets, the calories and lipids were transferred to the baby through the placenta. That modifies the metabolic profile of the baby."
The study also found a surprising link between an infant's size at birth and the mother's diet.
"The babies that were delivered to the high-calorie mothers were surprisingly smaller," Dr. Piedimonte said. "Interestingly enough, the weight was lower but the concentration of fat was higher. Later in life they developed higher weight and their metabolisms looked like the metabolisms of diabetic individuals. It's obvious that the metabolic profile of the baby is dramatically linked to the diet of the mother during pregnancy."
According to Dr. Piedimonte, mothers should watch the quantities they consume as well as the types of food they eat.
"We're getting dangerously close to 40 percent of children being obese or overweight," Dr. Piedimonte said, citing the large amounts of ingredients like high fructose corn syrup in packaged foods as a major reason for this. He suggested that expectant mothers (even those with faster metabolisms) should work closely with a dietician while pregnant, if they can.
"Diet should be discussed with experts. You can easily consume too many carbohydrates or lipids and that is going to have the ability to affect the metabolic status of the fetus," Dr. Piedimonte said. "This is not something that should be left to serendipity: A mother should very carefully assess the diet with an expert."
Since most pregnant readers may not have time (or the means) to schedule a session with a nutrition expert, we spoke with one instead, to get a better sense of what women should (and should not) eat during pregnancy. Dawn Lerman, a holistic nutritionist who regularly works with children and women, said it's important to note the distinction between good and bad fats.
"Healthy fats like nuts, avocados, flax seeds [and] chia seeds should make up at least 25 percent of your diet," she said. "A healthy, well-balanced diet that includes good fats helps balance mood and contributes to brain development."
With that being said, Lerman says even healthy fats should be eaten in moderation—a quarter to a half an avocado, for example, is a good portion size. Lerman recommended that pregnant women think in terms of "moderation, not deprivation—except when it comes to trans fats, sugar and processed carbs" and that women should balance their diets by eating equal amounts of protein, carbs and greens.
"You want to stay away from anything processed. It's just excess fat, excess sugar, excess carbs," Lerman said. "A pregnant woman should have six small meals a day and each one should have protein. Everything has to be part of a healthy diet. You don't want to live on McDonalds and ice cream—but twice a week if you have a little scoop of ice cream, that's fine. Think about it like this: What would you feed your baby? If your baby was sitting next to you, would you feed them a block of cheese? Or would you want a nice variety of healthy things?"