Walnut consumption in a weight reduction intervention: effects on body weight, biological measures, blood pressure and satiety.

BACKGROUND: Dietary strategies that help patients adhere to a weight reduction diet may increase the likelihood of weight loss maintenance and improved long-term health outcomes. Regular nut consumption has been associated with better weight management and less adiposity. The objective of this study was to compare the effects of a walnut-enriched reduced-energy diet to a standard reduced-energy-density diet on weight, cardiovascular disease risk factors, and satiety. METHODS: Overweight and obese men and women (n = 100) were randomly assigned to a standard reduced-energy-density diet or a walnut-enriched (15% of energy) reduced-energy diet in the context of a behavioral weight loss intervention. Measurements were obtained at baseline and 3- and 6-month clinic visits. Participants rated hunger, fullness and anticipated prospective consumption at 3 time points during the intervention. Body measurements, blood pressure, physical activity, lipids, tocopherols and fatty acids were analyzed using repeated measures mixed models. RESULTS: Both study groups reduced body weight, body mass index and waist circumference (time effect p < 0.001 for each). Change in weight was -9.4 (0.9)% vs. -8.9 (0.7)% (mean [SE]), for the standard vs. walnut-enriched diet groups, respectively. Systolic blood pressure decreased in both groups at 3 months, but only the walnut-enriched diet group maintained a lower systolic blood pressure at 6 months. The walnut-enriched diet group, but not the standard reduced-energy-density diet group, reduced total cholesterol and low-density lipoprotein cholesterol (LDL-C) at 6 months, from 203 to 194 mg/dL and 121 to 112 mg/dL, respectively (p < 0.05). Self-reported satiety was similar in the groups. CONCLUSIONS: These findings provide further evidence that a walnut-enriched reduced-energy diet can promote weight loss that is comparable to a standard reduced-energy-density diet in the context of a behavioral weight loss intervention. Although weight loss in response to both dietary strategies was associated with improvements in cardiovascular disease risk factors, the walnut-enriched diet promoted more favorable effects on LDL-C and systolic blood pressure. TRIAL REGISTRATION: The trial is registered at ( NCT02501889 ).

A walnut-containing meal had similar effects on early satiety, CCK, and PYY, but attenuated the postprandial GLP-1 and insulin response compared to a nut-free control meal.

Regular nut consumption is associated with lower adiposity and reduced weight gain in adulthood. Walnut feeding studies have observed minimal effect on body weight despite potential additional energy intake. Several mechanisms may explain why consuming nuts promotes weight control, including increased early phase satiety, possibly reflected in postprandial response of gastrointestinal and pancreatic peptides hypothesized to affect appetite. The purpose of this study was to compare postprandial insulin, glucagon and gastrointestinal peptide response and satiety following a meal with ∼54% of energy from walnuts or cream cheese, using a within-subject crossover study design in overweight/obese adults (N = 28). Sixty minutes after the walnut-containing meal, glucagon-like peptide-1 was lower than after the reference meal (p=0.0433), and peptide YY, cholecystokinin and ghrelin did not differ after the two meals. Sixty and 120 min after the walnut-containing meal, pancreatic polypeptide (p = 0.0014 and p = 0.0002) and glucose-dependent insulinotropic peptide (p < 0.0001 and p = 0.0079) were lower than after the reference meal, and 120 min after the walnut-containing meal, glucagon was higher (p=0.0069). Insulin and C-peptide increased at 60 min in response to both meals but were lower at 120 min after the walnut-containing meal (p=0.0349 and 0.0237, respectively). Satiety measures were similar after both meals. These findings fail to support the hypothesis that acute postprandial gastrointestinal peptide response to a walnut-containing meal contributes to increased satiety. However, inclusion of walnuts attenuated the postprandial insulin response, which may contribute to the more favorable lipid profile observed in association with regular walnut consumption.

Randomized clinical trial of portion-controlled prepackaged foods to promote weight loss.

OBJECTIVE: Providing portion-controlled prepackaged foods in a behavioral counseling intervention may promote more weight and fat loss than a standard self-selected diet. METHODS: The primary aim was to test whether providing portion-controlled prepackaged lunch and dinner entrées within a behavioral weight loss intervention promotes greater weight loss at 12 weeks compared to self-selected foods in adults with overweight/obesity. Other aims were to examine effects on biological factors, fitness, and meal satisfaction. One-half of those assigned to prepackaged entrées were provided items with a higher protein level (>25% energy) as an exploratory aim. RESULTS: Participants (N = 183) had a baseline weight of 95.9 (15.6) kg (mean [SD]) and BMI of 33.2 (3.5) kg/m(2) . Weight data at 12 weeks were available for 180 subjects. Weight loss for regular entrée, higher protein entrée, and control groups was 8.6 (3.9)%, 7.8 (5.1)%, and 6.0 (4.4)%, respectively (P < 0.05, intervention vs. control). Intervention participants lost more body fat than controls (5.7 [3.4] vs. 4.4 [3.3] kg, P < 0.05). CONCLUSIONS: A meal plan incorporating portion-controlled prepackaged entrées promotes greater weight and fat loss than a standard self-selected diet, with comparable meal satisfaction. Initial weight loss predicts long-term weight loss so these results are relevant to likelihood of longer term success.

Dietary restraint and low bone mass in female adolescent endurance runners.

BACKGROUND: Because disordered eating (DE) has been related to menstrual irregularity (MI) and low bone mineral density (BMD) in some studies of female athletes but not in others, it seems beneficial to assess the DE attitudes and behaviors most associated with these conditions. OBJECTIVE: We aimed to determine the relation between Eating Disorder Examination Questionnaire (EDE-Q) subscale scores, pathologic behaviors, MI, and low BMD in adolescent female runners. DESIGN: Participants were 93 female competitive cross-country runners 13-18 y old. The EDE-Q, composed of subscales for weight concern, shape concern, eating concern, and dietary restraint, was used to assess DE. Menstrual history was determined by using a questionnaire derived from a medical history form administered before participation in high school athletics. The International Society for Clinical Densitometry and the World Health Organization criterion of

Disordered eating and menstrual irregularity in high school athletes in lean-build and nonlean-build sports.

The authors' purpose was to determine the prevalence and compare associations of disordered eating (DE) and menstrual irregularity (MI) among high school athletes. The Eating Disorder Examination Questionnaire (EDE-Q) and a menstrual-history questionnaire were administered to 423 athletes (15.7 +/- 1.2 y, 61.2 +/- 10.2 kg) categorized as lean build (LB; n = 146) or nonlean build (NLB; n = 277). Among all athletes, 20.0% met the criteria for DE and 20.1% for MI. Although the prevalence of MI was higher in LB (26.7%) than NLB (16.6%) athletes (P = 0.01), no differences were found for DE. For both sport types, oligo/amenorrheic athletes consistently reported higher EDE-Q scores than eumenorrheic athletes (P < 0.05). Athletes with DE were over 2 times as likely (OR = 2.3, 95%CI: 1.3, 4.2) to report oligo/amenorrhea than athletes without DE. These data establish an association between DE and MI among high school athletes and indicate that LB athletes have more MI but not DE than NLB athletes.

Bone mineral density in female high school athletes: interactions of menstrual function and type of mechanical loading.

During adolescence, skeletal integrity of girls is largely dependent on menstrual function and impact exercise, yet currently there is limited research regarding the interaction between menstrual status and type of mechanical loading associated with various high school sports. Our purpose was to examine associations of menstrual status, type of mechanical loading, and bone mineral density (BMD) in female high school athletes participating in high/odd impact or repetitive/non-impact sport. Participants were 161 female high school athletes (15.7+/-1.3 years; 165.3+/-6.9 cm; 59.4+/-8.7 kg) representing high/odd impact (n=93, including soccer, softball, volleyball, tennis, lacrosse, and track sprinters and jumpers), or repetitive/non-impact sports (n=68, including swimmers, cross-country and track distance runners who participated in events>or=800 m). Areal BMD was measured by DXA at the spine (L1-L4), proximal femur, and total body. Menstrual status was determined by self-report. Athletes with primary, secondary or oligomenorrhea were combined into a single group (oligo/amenorrheic) and compared to eumenorrheic athletes. Analysis of covariance (ANCOVA) with Bonferroni post hoc comparisons adjusted for age, BMI, and gynecological age were used to compare BMD of athletes in combined mechanical loading and menstrual status groups. We found significantly greater total hip (p=0.04) and trochanter (p=0.02) BMD (g cm(-2)) among eumenorrheic high/odd impact compared to eumenorrheic repetitive/non-impact athletes, and greater spine (p=0.01) and trochanter (p=0.04) BMD among high/odd impact eumenorrheic athletes compared to repetitive/non-impact oligo/amenorrheic athletes. Chi-squared analysis of BMD Z-scores adjusted for gynecological age showed a significantly greater percentage of repetitive/non-impact athletes (33.9%) compared to high/odd impact athletes (11.8%) with low spine BMD for their age (BMD Z-score

Influence of sports participation and menarche on bone mineral density of female high school athletes.

Weight-bearing exercise during adolescence may enhance peak bone mineral density (BMD) and reduce osteoporosis risk. The association of sports participation before and after menarche with areal BMD (by central DXA) was investigated in 99 female high school athletes (age 15.5+/-1.3 year). The frequency and duration of structured sports (school-based or other organized team) were assessed using an interviewer-assisted questionnaire. Overall, the average number of years of weight-bearing sport participation was 7.4+/-3.4 years; 72% of the athletes began sport participation before menarche. Training patterns and BMD were examined by tertiles of yearly weight-bearing sport participation (hours/year) before (WBpre), after (WBpost) menarche, and in total (WBtotal). After adjusting for chronological age, gynecological age, and BMI, compared to athletes in the WBtotal low tertile, athletes in the WBtotal high tertile had significantly greater BMD at the spine (p=0.009), total hip (p=0.03), trochanter (p=0.03), and total body (p=0.009). Similar patterns were found by WBpre or WBpost status, separately, with the exception of spine BMD which was significantly different across tertiles in WBpost only (p<0.01). While the number of years of participation was similar across tertiles of WBtotal, the number of months/year was significantly greater among athletes in the high tertile than athletes in the low tertile (9.2+/-3.4 month/year versus 5.0+/-2.9 month/year, respectively (p<0.001)). These results indicate that near year-round participation in structured weight-bearing sports during early adolescence may help young girls optimize bone mineral accrual during these critical years, and may decrease their risk of osteoporosis with advancing age.

Prevalence of the female athlete triad syndrome among high school athletes.

OBJECTIVE: To estimate the prevalence of the female athlete triad (disordered eating, menstrual irregularity, and low bone mass) among high school athletes. DESIGN: Observational cross-sectional study. SETTING: High school. PARTICIPANTS: Female athletes (n= 170) representing 8 sports were recruited from 6 high schools in southern California. MAIN OUTCOME MEASURES: Disordered eating and menstrual status were determined by interviewer-assisted questionnaires. Bone mineral density was measured by dual-energy x-ray absorptiometry of the hip, spine (L1-L4), and total body. RESULTS: Among all athletes, 18.2%, 23.5%, and 21.8% met the criteria for disordered eating, menstrual irregularity, and low bone mass, respectively. Ten girls (5.9%) met criteria for 2 components of the triad, and 2 girls (1.2%) met criteria for all 3 components. Oligomenorrheic/amenorrheic athletes had higher mean +/- SD eating restraint (1.55 +/- 1.60 vs 1.04 +/- 1.27; P = .02) and Eating Disorder Examination Questionnaire global scores (1.68 +/- 1.20 vs 1.33 +/- 1.14; P = .03) than eumenorrheic athletes. After controlling for age, age at menarche, body mass index, race/ethnicity, and sport type, athletes with oligomenorrhea/amenorrhea had significantly lower mean +/- SD bone mineral densities for the trochanter (0.884 +/- 0.090 g . cm(-2)) than eumenorrheic athletes (0.933 +/- 0.130 g . cm(-2); P = .04). CONCLUSIONS: The prevalence of the full female athlete triad was low in our sample; however, a substantial percentage of the athletes may be at risk for long-term health consequences associated with disordered eating, menstrual irregularity, or low bone mass. Preparticipation screening to identify these components should be encouraged as a preventive approach to identify high-risk athletes.