Pregnancy weight restriction: Harming without helping

by Ellyn Satter, Registered Dietitian and Family Therapist

Restricting weight gain during pregnancy does way more harm than good to both the mother and the baby. Standards for weight gain increase the risk of undermining the mother’s metabolism as well as distorting feeding dynamics throughout the child’s growing-up years. Attitudes of negativity and control toward eating and weight management implanted during pregnancy are likely to persist and generalize to feeding the infant, child and family. While Institute of Medicine weight-gain guidelines are moderate and offer a range of target weights, they are still absolute. Achieving such weight standards during pregnancy is no more realistic or possible than achieving stated weight standards at any other time in the life cycle. 

Diets don’t work during pregnancy, either

Absolute standards teach the pregnant woman to distrust and control her body, undermine her eating competence, and disrupt her metabolism.

 

The studies noted in this newsletter show that weight-loss efforts are no more effective in safely producing sustained weight loss when applied during pregnancy than at any other time. In fact, food restriction and striving for a defined weight-gain outcome is particularly dangerous during pregnancy, as demonstrated by the dietary behavior of pregnant women who have weight concerns.

• Most women diet, most of the time. 78% of women are attempting to lose weight or maintain weight loss at any one time.¹ ”Overweight” women are particularly likely to be chronic dieters.
• In contrast to women in the 1970s that we discussed in part 1 or this series, today’s chronically dieting women don’t know how to ”eat as much as they are hungry for and gain weight accordingly.” Chronic dieters lose touch with their internal regulators of hunger, appetite and satiety. When the pregnancy directive to stop dieting deprives them of their external guidelines for eating, they have neither internal nor external controls, and their eating is likely to become chaotic.
• Many restrained eaters (chronic dieters) gain too much weight during pregnancy, others gain too little.²
• A high proportion of women classified as overweight or obese, those most likely to be restrained eaters, gain more than IOM-recommended amounts during pregnancy.³
• Compared with controls, food restriction interventions produce excess weight gain in many pregnant women.^4,5
• Pregnant women who strive to limit weight gain resort to extreme and potentially destructive weight-restrictive behaviors: not eating before an obstetric visit, trying not to look pregnant early in pregnancy, and trying to adjust monthly weight gain based on previous gain.⁶
• Eating infrequently increases the risk of preterm delivery⁷ as does going without food for prolonged periods.⁸
• Women who report weight-restrictive behaviors have higher anxiety, depression, anger, stress, and demoralization during pregnancy. These reactions are unrelated to the individual’s absolute body weight or BMI. Weight-restricting women have negative attitudes about weight gain even if they gain within recommended ranges.⁶
• In a group of women having low-risk, normal pregnancies, those who were more fatigued, stressed, and anxious consumed a greater amount of food and lower-nutrient food.⁹
• Only 30 to 40% of women gain weight within IOM guidelines,¹⁰ and women regularly achieve good outcomes with weight gains that are above or below recommendations.³

Mother and baby metabolisms suffer

Restricting food intake during pregnancy distorts not only eating attitudes and behaviors, but also metabolism. The predominant nutritional requirement during pregnancy is calories. If the mother doesn’t consume enough calories, she breaks down dietary protein and her own muscle and organ tissue into blood glucose. High levels of the hormone that does the work, glucocorticoid, have been implicated in predisposing low-birth-weight infants to susceptibility to metabolic syndrome in later life.¹¹

Pregnancy is the time to learn to trust your body

Such fearful, negative and controlling attitudes and behaviors represent a tragic loss when viewed from the perspective of what is possible. Pregnancy gives each woman an opportunity to gain appreciation for her body and for the miracle of giving birth. It can teach her be loving and nurturing with herself as she gets support in taking good care of herself with food, detecting and trusting information coming from her body to guide her eating and respecting her own distinctive patterns of weight gain.

For help with managing family meals, see Ellyn Satter’s Secrets of Feeding a Healthy Family.