Dieters Gain More Weight in Pregnancy

Care providers often push "obese" women to lose weight before pregnancy in hopes that weight loss will reduce complications and make for a healthier pregnancy.

However, one consequence they often fail to consider is that the woman who loses weight before pregnancy often gains excessively during pregnancy.

This is logical; the body thinks it is starving already; once pregnant it feels it has to get even more efficient in order to sustain the mother and provide enough energy for the baby to grow. Thus, the body holds on even more to every calorie it does get and the woman experiences a higher weight gain during pregnancy, even though she may be eating perfectly reasonably.

Here is a brand-new study showing that women who practice "dietary restraint" (dieting, weight cycling, restrained eating) before pregnancy tend to gain more weight in pregnancy. The study noted:

Multivariable analysis revealed that restrained eating, weight cycling and dieting were associated with higher absolute weight gain, whilst weight cycling only was associated with excessive weight gain.

This is not the first study to find a higher gain in women who diet before pregnancy. Another study in 2008 had similar findings. It noted:

Restrained eating behaviors were associated with weight gains above the Institute of Medicine's recommendations for normal, overweight, and obese women.

And another study from 2013 showed that low-income women who experienced food insecurity and have a history of dieting may be particularly at risk for high gain during pregnancy.

Yet most caregivers continue to recommend weight loss before pregnancy to high-BMI women, and many researchers call quite aggressively for it. They do not seem to realize that the trade-off for significant weight loss before pregnancy may well be a high weight gain during pregnancy.

This is especially troublesome considering the intense pressure some care providers place on obese women to restrict their weight gain to almost nothing during pregnancy. It's like they are setting up women of size to fail from the get-go.

A better approach is to encourage women of all sizes to practice Health At Every Size®, which means to place the emphasis on eating well and getting regular exercise without emphasizing weight loss or the scale. 

There's nothing wrong with encouraging healthy habits before pregnancy, and this can be an important part of pre-conception care ─ but the emphasis on weight loss before pregnancy at all costs may be counter-productive.


References

Appetite. 2016 Dec 1;107:501-510. doi: 10.1016/j.appet.2016.08.103. Epub 2016 Aug 19. Effects of dietary restraint and weight gain attitudes on gestational weight gain. Heery E, Wall PG, Kelleher CC, McAuliffe FM. PMID: 27545671

The aim of this study was to examine the impact of dietary restraint and attitudes to weight gain on gestational weight gain. This is a prospective cohort study of 799 women recruited at their first antenatal care visit. They provided information on pre-pregnancy dietary restraint behaviours (weight cycling, dieting and restrained eating) and attitudes to weight gain during pregnancy at a mean of 15 weeks' gestation. We examined the relationship of these variables with absolute gestational weight gain and both insufficient and excessive gestational weight gain, as defined by the Institute of Medicine recommendations. Multivariable analysis revealed that restrained eating, weight cycling and dieting were associated with higher absolute weight gain, whilst weight cycling only was associated with excessive weight gain. There was no evidence that the relationships between the dietary restraint measures and the weight gain outcomes were mediated by pregnancy-associated change in food intake. Increased concern about weight gain during pregnancy was independently associated with higher absolute weight gain and excessive weight gain. These relationships were attenuated following adjustments for pregnancy-associated change in food intake. These findings suggest that in early pregnancy, both a history of fluctuations in body weight and worry about gestational weight gain, are indicators of high pregnancy weight gain. Concern about weight gain during pregnancy seems to partly arise from an awareness of increased food intake since becoming pregnant. Prenatal dietary counselling should include consideration of past dieting practices and attitudes to pregnancy weight gain.

J Am Diet Assoc. 2008 Oct;108(10):1646-53. doi: 10.1016/j.jada.2008.07.016. Dietary restraint and gestational weight gain. Mumford SL, Siega-Riz AM, Herring A, Evenson KR. PMID: 18926129

OBJECTIVE: To determine whether a history of preconceptional dieting and restrained eating was related to higher weight gains in pregnancy. DESIGN: Dieting practices were assessed among a prospective cohort of pregnant women using the Revised Restraint Scale. Women were classified on three separate subscales as restrained eaters, dieters, and weight cyclers. SUBJECTS: Participants included 1,223 women in the Pregnancy, Infection, and Nutrition Study. MAIN OUTCOME MEASURES: Total gestational weight gain and adequacy of weight gain (ratio of observed/expected weight gain based on Institute of Medicine recommendations). STATISTICAL ANALYSES PERFORMED: Multiple linear regression was used to model the two weight-gain outcomes, while controlling for potential confounders including physical activity and weight-gain attitudes. RESULTS: There was a positive association between each subscale and total weight gain, as well as adequacy of weight gain. Women classified as cyclers gained an average of 2 kg more than noncyclers and showed higher observed/expected ratios by 0.2 units. Among restrained eaters and dieters, there was a differential effect by body mass index. With the exception of underweight women, all other weight status women with a history of dieting or restrained eating gained more weight during pregnancy and had higher adequacy of weight gain ratios. In contrast, underweight women with a history of restrained eating behaviors gained less weight compared to underweight women without those behaviors. CONCLUSIONS: Restrained eating behaviors were associated with weight gains above the Institute of Medicine's recommendations for normal, overweight, and obese women, and weight gains below the recommendations for underweight women. Excessive gestational weight gain is of concern because of its association with postpartum weight retention. The dietary restraint tool is useful for identifying women who would benefit from nutritional counseling prior to or during pregnancy with regard to achieving targeted weight-gain recommendations.

Appetite. 2013 Jun;65:178-84. doi: 10.1016/j.appet.2013.01.018. Epub 2013 Feb 10. Food insecurity with past experience of restrained eating is a recipe for increased gestational weight gain. Laraia B, Epel E, Siega-Riz AM. PMID: 23402720

Food insecurity is linked to higher weight gain in pregnancy, as is dietary restraint. We hypothesized that pregnant women exposed to marginal food insecurity, and who reported dietary restraint before pregnancy, will paradoxically show the greatest weight gain. Weight outcomes were defined as total kilograms, observed-to-recommended weight gain ratio, and categorized as adequate, inadequate or excessive weight gain based on 2009 Institute of Medicine guidelines. A likelihood ratio test assessed the interaction between marginal food insecurity and dietary restraint and found significant. Adjusted multivariate regression and multinomial logistic models were used to estimate weight gain outcomes. In adjusted models stratified by dietary restraint, marginal insecurity and low restraint was significantly associated with lower weight gain and weight gain ratio compared to food secure and low restraint. Conversely, marginal insecurity and high restraint was significantly associated with higher weight gain and weight gain ratio compared to food secure and high restraint. Marginal insecurity with high restraint was significantly associated with excessive weight gain. Models were consistent when restricted to low-income women and full-term deliveries. In the presence of marginal food insecurity, women who struggle with weight and dieting issues may be at risk for excessive weight gain.