Changes in Food Group Consumption and Dietary Quality in Overweight Postpartum Women. A thesis submitted to the. Graduate School

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2 Changes in Food Group Consumption and Dietary Quality in Overweight Postpartum Women A thesis submitted to the Graduate School of the University of Cincinnati in partial fulfillment of the requirements for the degree of Master of Science in Nutrition in the Department of Nutritional Sciences of the College of Allied Health Sciences By Julia Piazza July 14, 2011 B.A., The Ohio State University, 2007 Committee Chair: Grace Falciglia, Ph.D., R.D.

3 ABSTRACT: Background: The American Society for Nutrition has identified the postpartum period as a possible time to enhance dietary quality, seeing that the mothers are highly motivated to instill proper eating habits for themselves and their children. This study was designed to determine if a clinically based intervention would be effective in enhancing the dietary quality of postpartum women. Increasing vegetable consumption (particularly deep-yellow and dark-green vegetables) was the main target of the intervention, while also emphasizing the importance of an overall balanced diet. Methods: Two groups of postpartum women (30 intervention and 25 control) participated in this study. These participants were assigned to either the intervention or control group, which determined whether they were given nutrition counseling or not. The 6 month-long dietary intervention consisted of one face-to-face counseling session conducted by a nutrition professional, and two follow-up phone calls. Vegetable and caloric intakes were assessed at baseline and post-treatment. Results: From baseline to post-intervention, vegetable consumption significantly increased in the intervention group (p<.001). Target vegetables and total yellow vegetables also increased significantly from baseline to post-intervention in the intervention group (p<.01). Additionally, the increases of vegetable consumption and total yellow vegetable consumption were significantly higher in the intervention group compared to the control group (p<.01). Carrot consumption in the intervention group significantly increased from baseline to post-intervention and this increase was significantly greater than that in the control group (p<.05). Conclusion: This postpartum dietary intervention was effective in enhancing dietary quality, specifically by significantly increasing vegetable intake. ii

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5 TABLE OF CONTENTS Page List of Tables v Introduction 1 Purpose 3 Hypothesis 4 Methods Subjects 4 Dietary Intervention 5 Measures 7 Data Analysis 8 Results Demographics 8 Dietary Outcomes 9 Discussion 11 Conclusion 12 References 13 iv

6 List of Tables Table 1 7 Table 2 9 Table 3 10 v

7 INTRODUCTION Rising obesity rates among women, in addition to the importance of maintaining a normal body weight during the reproductive years, suggests a growing need for nutrition counseling in this population. Currently, about 35.5 % of women are considered obese, and that number has continued to increase over the past decade (Flegal, 2010). Pregnancy is a potential contributing factor to overweight and obesity among women (Ostbye, 2009). Each year, approximately four million American women give birth, and it is expected that nearly 25% experience major weight retention after pregnancy (Phelan, 2010). It has also been noted that women who go into pregnancy overweight or obese are at an elevated risk of retaining the weight at 12 months postpartum (Keller, 2008). Postpartum weight retention also increases a woman s chance for pregnancy related complications and serious health complications in the offspring (Nuss, 2007). The postpartum period is a critical time for women in terms of reaching optimal weight, however more than two-thirds of women who attend their obstetrician 6-week postpartum appointment have not attained their pre-pregnancy weight (Walker, 2004). Although women often make changes in their diet during pregnancy in an attempt to become healthier, these changes are often not maintained though the postpartum period (Fowles, 2006). The American Dietetic Association has suggested that all overweight or obese women of reproductive age receive counseling on the importance of diet and exercise prior to, during and after pregnancy (ADA, 2009). Perhaps with the proper knowledge, postpartum women may achieve their prepregnancy weight in a healthier manner. A previous study conducted to assess nutrition knowledge during early and late postpartum in relation to weight retention at 1-year postpartum found that women who retained 1

8 less than 5% of weight gained during pregnancy had greater knowledge of nutrition at 0 and 12 months postpartum (Nuss, 2007). This suggests that nutrition related knowledge can be used as a tool to combat excess weight retention in the postpartum period. Additional findings suggest that most women at 6 months postpartum do not consume the recommended number of bread, vegetable and milk servings (George, 2005). Also, Olsen 2005 found that women at 6 months postpartum were not consuming adequate amounts of fruits and vegetables. These findings show that inadequate intake of certain food groups among postpartum women is a current issue. There are many reasons why postpartum women may experience a decline in the quality of their diet. This transition period may include changes in quality of sleep, free-time, occupational status, and overall attention to one s own needs. Dietary behaviors may be influenced by the result of women adapting to their maternal role (George, 2005). A study conducted to determine the impact of a structured diet and exercise regimen on weight loss in postpartum women found that those who committed to the intervention class for 12 weeks experienced a higher likelihood of successful weight loss that persisted at one year postpartum (O Toole, 2003). Another study regarding postpartum weight retention looked at the impact of excess pregnancy weight gain and failure to lose weight by 6 months postpartum on excess weight 8-10 years later (Rooney, 2002). The women who had been able to lose the weight they had gained during pregnancy were on average only 2.4 kg heavier at long-term follow up as opposed to those who had retained the weight at 6 months postpartum that were on average 8.3 kg heavier at long-term follow up (Rooney, 2002). These findings point to the long-term issue of postpartum weight retention. 2

9 Seeing as how healthful dietary practices and a return to pre-pregnancy weight are of significant importance in the prevention of obesity for women, it is important to determine other factors besides knowledge that will help avoid postpartum weight retention (Cahill, 2010). A study looking at diet quality and food intake of low income postpartum women determined that motivation was also a key factor in determining postpartum weight gain. Women that had high fruit and vegetable availability consumed more vegetables, in addition to those that had a higher taste preference for vegetables (Cahill, 2010). This study suggests the importance of providing women with the proper nutrition knowledge related to developing taste preference for vegetables in addition to offering suggestions to help increase the availability of vegetables in the home. Part of the data used for this thesis came from a previous study (Smith, 2006). In the present study however, only the participants that were considered overweight (BMI > 25) were selected. Also, the previous study only contained an intervention group so a control group was added to this particular study. The new data base supported this thesis with a focus only on food groups and overall dietary quality as an outcome of the intervention. PURPOSE To evaluate the effectiveness of a clinical-based intervention in enhancing the dietary quality of overweight postpartum women. Increasing vegetable consumption (particularly deepyellow and dark-green vegetables) was the main target of the intervention, while also emphasizing the importance of an overall balanced diet. 3

10 HYPOTHESIS The hypothesis of the study was that the postpartum period would be a good time to initiate a clinical-based intervention in an attempt to improve diet quality. Specifically, an increase in vegetable consumption would help to achieve this overall improvement in the diet. METHODS Subjects Women 18 to 40 years of age were screened at their six week postpartum appointment at Samaritan Obstetrics in Cincinnati. Exclusion criteria included anyone who had a BMI < 25, a preterm infant, multiple infants, high risk pregnancy, in-vitro fertilization, was on a special diet, already received nutrition education through the Special Supplemental Program for Women, Infants and Children, and lacked full medical clearance from a physician to participate. Study procedures were approved by the University of Cincinnati Institutional Review Board. Thirty-five women who received a dietary intervention from a pilot study (Smith, 2006) were matched with thirty-one women from a control group from a similar study. Baseline measurements were recorded within two weeks of recruitment and post-treatment assessment took place at 6 months post-delivery, either after nutrition counseling (intervention) or without counseling (control). Fifty-five postpartum women completed the study (30 intervention and 25 control; 83% retention). Some of the most common reasons for discontinuing the study included lack of time, relocation, or no longer interested in participating. No differences in demographic data were found among the participants that discontinued the study and the participants that completed the study. 4

11 Dietary Intervention The Social Cognitive Theory (SCT) provided the theoretical basis for the intervention (Bandura, 1978). The SCT explains behavior in terms of a reciprocal model in which behavior, personal factors, and environmental influences all interact. Key constructs of SCT that were relevant to this intervention included clear expectations (increase diet quality), environment (availability of vegetables), self-efficacy (choosing vegetables in a variety of settings), and selfmonitoring weekly vegetable intake. The 4 month-long dietary intervention consisted of one face-to-face counseling session conducted by a nutrition professional, two follow-up phone calls, and three pamphlets that were mailed to the mother s home. The counseling session took place in the obstetrician s office approximately 2 months after delivery and usually lasted about 60 minutes. The counseling session discussed the mother s current eating habits and provided instruction on how to increase vegetable intake and adapt a healthier diet. Shopping, washing, storage, preparation and cooking of vegetables were some of the skills taught during the counseling sessions. Mothers were also provided with recipes that utilized a variety of vegetables including the target vegetables. The follow-up phone calls discussed progress and helped the participants set new goals for increasing vegetable intake. The pamphlets provided more detailed information on target vegetables. A well-balanced diet was encouraged in the intervention group, with a major goal to increase vegetable consumption. Specifically, deep-yellow and dark green vegetables were recommended including carrots, sweet potatoes, winter squash, green peas and green beans (referred to as target vegetables). These vegetables were chosen as a main focus of the intervention because they are naturally low in calories, fat, cholesterol and sodium; they provide 5

12 essential vitamins, minerals and dietary fiber; and they are 70-95% water which helps to provide satiety. In addition, vegetables are commonly underrepresented in the typical America diet, but their inclusion is essential to a healthy diet. The nutrition counseling provided to the intervention group recommended a total of five servings of vegetables per day, with two of those servings coming from the target vegetables. Calorie needs were determined by feeding method (breast-feeding or formula-feeding). Those that were exclusively breast-feeding were advised to consume 2,000 kcal/day to support breastfeeding and energy requirements, in addition to facilitating gradual loss of postpartum weight (2 pounds per month). Formula-feeding participants were advised to consume 1,500 kcal/day because they did not need the extra 500 kcal to support breast-feeding and they wanted to see gradual weight loss (2 pounds per month). If combination feeding methods were being used, the calorie needs were adjusted based on intensity of breast-feeding. An eating plan for each kilocalorie level based on the food guide MyPyramid was developed (USDA, 2005). Dietary goals were the same for both food plans: (1) Let MyPyramid guide your food choices; (2) Eat at least 5 servings of vegetables daily; (3) Choose at least 2 servings of vegetables from the target vegetables: carrots, sweet potatoes, winter squash, green beans and peas. The participants in the intervention group were given specific food group outlines based on feeding method, as outlined in Table 1. The mothers in the control group received one brochure by mail containing nutrition information from MyPyramid for either breast-feeding or formula-feeding mothers. 6

13 Table 1. Intervention Food Plan for Breastfeeding and Formula Feeding Mothers. Food Plan Breastfeeding mothers Formula feeding mothers Calories a Servings/day b Meat (3 oz) Grain (1oz/1/2c) 7 5 Milk (1c) 3 3 Fruit (1/2c) 4 3 Vegetables (1/2c ) 5 5 a Calorie needs based on weight and lactation status b Amount of servings per food group meets the DRI macronutrient recommended intake ranges Measures Participants self-reported age, feeding-method, race and education level at baseline. In addition, height and weight were measured using a calibrated triple-beam balance scale and a wall-mounted stadiometer. Each measure was taken twice and the average of the two readings was calculated. Body mass index (BMI) was calculated as kg/m2. A nutrition professional collected information about the participants diet at baseline and 6 months post-delivery. Food intake was assessed using three 24-hour food records collected over a 1-week period before each assessment visit. The postpartum women were explained the 2-dimensional food portion size model (Millen, 1996) in an attempt to minimize food recall errors and enhance accuracy of food volumes and dimensions. Once the food records were collected, they were analyzed for caloric intake and overall food patterns, including meat, grain, fruit, milk and vegetable intake. The data from the dietary recalls was used to determine the level at which the participants adhered to intervention goals. 7

14 Data Analysis University of Minnesota s Nutrition Data System for Research 2010 was used to analyze the 24-hour food recalls and provide calculations of food groups (UMN Nutrition Coordinating Center, 2011). Descriptive statistics were run to summarize age, race, education level, height, weight, Body Mass Index (BMI), and feeding method. The difference of the demographics between intervention group and control groups were examined by independent students t-test and Chi-square test. The box plot was run and extreme outliers were identified as having values more than three times the height of the boxes. The ouliers were replaced with the mean of the original values. Paired t-tests were used to examine changes in food group intakes between preand post-tests. Food group consumption was adjusted per 1,000 calories to account for the significant difference in calorie consumption at baseline between the intervention and control groups. The differences in the changes between intervention and control groups were examined using independent t-tests. RESULTS Demographics Among the 66 postpartum women that were enrolled in the study, 35 women were randomized into the intervention group and 30 participants completed the study (5 drop outs). Thirty-one women were randomized into the control group and 25 completed the study (6 drop outs). The average age of the participants at baseline was 29.3 years (intervention) and 30.5 years (control). Baseline BMI scores averaged 29.7 in the intervention group and 29.0 in the control group. The majority of both the control and intervention groups were breastfeeding at baseline and the majorities of both groups were white/non-hispanic and completed college. At baseline, 8

15 there were no significant differences between the intervention and control groups in terms of age, race, education, BMI, and feeding method (Table 2). Table 2. Mean Values (SD) and Number (n, %) of Baseline Characteristics of the Study Participants Demographics Intervention (N = 30) Mean (SD) Control (N = 25) Mean (SD) Age (yrs) 29.3 (3.1) 30.5 (4.0) Height (m) 1.7 (0.1) 1.7 (0.1) Weight (kg) 82.2 (10.3) 81.3 (13.4) BMI 29.7 (3.8) 29.0 (3.8) Feeding Method Breast-Feeding (%) Formula-feeding (%) Race White/non-Hispanic (%) White/Hispanic (%) African-American (%) Asian (%) Other (%) Education < High School (%) Some college, associates, or vocational (%) College (%) Dietary Outcomes From baseline to 6 months post-delivery, total vegetable consumption significantly increased in the intervention group (p<.001). Target vegetables and total yellow vegetables also increased significantly from baseline to post-intervention in the intervention group (p<.01). Additionally, the increases of total vegetable consumption and total yellow vegetable consumption were significantly higher in the intervention group compared to the control group (p<.01). Carrot consumption in the intervention group significantly increased from baseline to post-intervention and this increase was significantly greater than that in the control group 9

16 (p<.05). In the control group, total vegetables, total target vegetables, total yellow vegetables did not experience any increase from baseline to 6 months post-delivery. The total green vegetables did not increase in the intervention or the control group. The consumption of grains decreased in the intervention group from baseline to 6 months post-delivery; this decrease was significantly different than the change from baseline to 6 months post-delivery in the control group, which experienced a slight increase in total grain consumption (Table 3). Table 3. Three-day mean intakes for food groups and vegetable consumption at baseline (2 months post-delivery) and 6 months post-delivery and the change between them. Food Groups Intervention (N = 30) Control (N = 25) (servings) Baseline Mean (SD) 6 Months Post- Change Mean (SD) Baseline Mean (SD) 6 Months Post- Change Mean (SD) Delivery (SD) Delivery Mean (SD) Meat 1.2 (0.5) 1.4 (0.6) 0.2 (0.8) 3.0 (0.8) 2.8 (1.1) -0.2 (1.4) Grain 3.2 ( (0.7) -0.4 (1.1)* 3.6 (0.7) 3.8 (0.9) 0.2 (1.0) Milk 1.1 (0.3) 1.0 (0.4) -0.1 (0.4) 1.1 (0.6) 1.1 (0.6) 0.0 (0.7) Fruit 0.9 (0.7) 0.9 (0.6) 0.0 (0.8) 1.0 (0.4) 0.9 (0.7) -0.1 (1.0) Vegetables 1.8 (0.8) 2.9 (1.3) a 1.1 (1.6)** 2.0 (0.9) 2.0 (0.9) 0.0 (1.1) Target 0.3 (0.4) 0.6 (0.6) b 0.3 (0.5) 0.3 (0.3) 0.3 (0.6) 0.0 (0.6) Vegetables Total Yellow 0.2 (0.4) 0.5 (0.5) b 0.3 (0.4)** 0.2 (0.2) 0.2 (0.2) 0.0 (0.2) Vegetables Total Green 0.1 (0.1) 0.2 (0.3) 0.1 (0.3) 0.1 (0.2) 0.2 (0.6) 0.1 (0.6) Vegetables Green Peas 0.1 (0.1) 0.1 (0.2) 0.0 (0.3) 0.0 (0.1) 0.0 (0.0) 0.0 (0.1) Green Beans 0.1 (0.1) 0.1 (0.1) 0.0 (0.1) 0.1 (0.2) 0.2 (0.6) 0.1 (0.6) Carrots 0.2 (0.3) 0.4 (0.5) c 0.2 (0.4)* 0.2 (0.2) 0.1 (0.2) -0.1 (0.2) Sweet 0.0 (0.5) 0.1 (0.3) 0.1 (0.2) 0.0 (0.1) 0.0 (0.1) 0.0 (0.1) Potatoes Squash 0.0 (0.3) 0.0 (0.1) 0.0 (0.1) 0.0 (0.1) 0.0 (0.1) 0.0 (0.1) a = significant difference from baseline to 6 months post-delivery p < b = significant difference from baseline to 6 months post-delivery p < 0.01 c = significant difference from baseline to 6 months post-delivery p < 0.1 *= significant difference in change between control and intervention group p < 0.1 **= significant difference in change between control and intervention group p <

17 DISCUSSION This study provides evidence to support an association between a dietary intervention emphasizing vegetables and the improvements of diet quality of postpartum women, thus recognizing the postpartum period as a teachable time. Mothers in the intervention group ate more total vegetables, target vegetables, total yellow vegetables, and carrots after their intervention, while the control group experienced no improvements in vegetable intake. Unfortunately, there was no significant increase in total green vegetable consumption in the intervention group. Green vegetables are considered to be bitter so multiple exposures may be necessary for one to learn to like them. A study was conducted on fruit and vegetable intake of Americans, and it was found that the dark green vegetable intake was surprisingly low. Even when increases were found in overall vegetable intake, daily intake of dark green vegetables was less than a half of a serving (Johnston, 2000). This suggests a need for repeated exposure to dark green vegetables in order for them to be incorporated in more peoples diets. Another previous study has also shown that a program consisting of a structured diet and physical activity contributed to successful weight loss that persisted at one-year postpartum (O Toole, 2003). In addition, He, 2004 found that increased vegetable consumption is associated with reduced risk of weight gain and obesity development. Therefore, the study confirms previous research on the importance of nutrition education in this population. 11

18 CONCLUSION Postpartum dietary intervention appears to be effective in enhancing dietary quality, specifically by significantly increasing vegetable intake. The dietary intervention suggests that providing instruction on how to increase vegetable intake and adapt a healthier diet may be a successful way to help modify postpartum diet quality. In conclusion, these findings suggest that dietary counseling should be included in the follow-up of postpartum in order to enhance the dietary intake of postpartum women. 12

19 References 1. American Dietetic Association (2009) Position of the American Dietetic Association and American Society for Nutrition: obesity, reproduction, and pregnancy outcomes. Journal of the American Dietetic Association 109, Bandura A. (1978) The self-system in reciprocal determinism. American Psychology 33: Cahill JM, Freeland-Graves JH, Shah BS. (2010) Motivations to eat are related to diet quality and food intake in overweight and obsess, low income women in early postpartum. Appetite 55(2), Flegal KM, Carroll MD, Ogden CL. (2010) Prevalence and trends in obesity among US adults, Journal of the American Medical Association 303(3), Fowles E. & Walker L. (2006) Correlates of dietary quality and weight retention in postpartum women. Journal of Community Health Nursing 23(3), George G, Hanss-Nuss H, Milani TJ. (2005) Food choices of low-income women during pregnancy and postpartum. Journal of the American Dietetic Association 105, He K., Hu F.B., Colditz G.A., Manson J.E., Willett, W.C. & Liu S. (2004) Changes in intake of fruits and vegetables in relation to risk of obesity and weight gain among middle-aged women. International Journal of Obesity 28, Johnston C, Taylor CA, Hampl JS. (2000) More Americans are eating 5 a day but intakes of dark green and cruciferous vegetables remain low. Journal of Nutrition 5, Keller C, Records K, Ainsworth B. (2008) Interventions for weight management in postpartum women. JOGNN 37, Millen B, Morgan J. (1996) The 2D Food Portion Visual. Framingham, Mass: Nutrition Consulting Enterprises. 11. Nuss H, Freeland-Graves J, Clarke K. (2007) Greater nutrition knowledge is associated with lower 1-year postpartum weight retention in low-income women. Journal of the American Dietetic Association 107, Olsen, C. (2005) Tracking food choices across the transition to motherhood. J Nutr Educ Behav 37, Ostbye T, Krause K, Lovelady CA (2009) Active mothers postpartum a randomized controlled weight loss intervention trial. Am J Prev Med 37(3), O Toole ML, Sawicki MA, Artal R. (2003) Structured diet and physical activity prevent postpartum weight retention. Journal of Women s Health 12,

20 15. Phelan S, Smith K, Steele JM. (2010) What type of weight loss program do postpartum women want? Treatment preferences of postpartum women in two community settings. Journal of Health Promotion 8(1), Rooney B.L. & Schauberger C.W. (2002) Excess pregnancy weight gain and long term obesity: one decade later. Obstetrics & Gynecology 100(2), Smith, SL. (2006) A dietary intervention focusing on vegetable intake in postpartum mothers with concomitant effects on vegetable intake. Master s Thesis, University of Cincinnati. 18. University of Minnesota Nutrition Coordinating Center (2011) Nutrition Data System for Research (NDSR). Avaliable at: (last accessed 20 June 2011). 19. Walker LO, Timmerman GM, Sterling BS. (2004) Do low income women attain their prepregnant weight by the 6 th week of postpartum? Ethnicity and Disease 14,