StandUPTV: Preparation and optimization phases of a mHealth intervention to reduce sedentary screen time in adults.

Recreational sedentary screen time (rSST) is the most prevalent sedentary behavior for adults outside of work, school, and sleep, and is strongly linked to poor health. StandUPTV is a mHealth trial that uses the Multiphase Optimization Strategy (MOST) framework to develop and evaluate the efficacy of three theory-based strategies for reducing rSST among adults. This paper describes the preparation and optimization phases of StandUPTV within the MOST framework. We identified three candidate components based on previous literature: (a) rSST electronic lockout (LOCKOUT), which restricts rSST through electronic means; (b) adaptive prompts (TEXT), which provides adaptive prompts based on rSST behaviors; and (c) earning rSST through increased moderate-vigorous physical activity (MVPA) participation (EARN). We also describe the mHealth iterative design process and the selection of an optimization objective. Finally, we describe the protocol of the optimization randomized controlled trial using a 23 factorial experimental design. We will enroll 240 individuals aged 23-64 y who engage in >3 h/day of rSST. All participants will receive a target to reduce rSST by 50% and be randomized to one of 8 combinations representing all components and component levels: LOCKOUT (yes vs. no), TEXT (yes vs. no), and EARN (yes vs. no). Results will support the selection of the components for the intervention package that meet the optimization objective and are acceptable to participants. The optimized intervention will be tested in a future evaluation randomized trial to examine reductions in rSST on health outcomes among adults.

Randomized controlled trial of prepregnancy lifestyle intervention to reduce recurrence of gestational diabetes mellitus.

BACKGROUND: Preconception lifestyle intervention holds potential for reducing gestational diabetes mellitus, but clinical trial data are lacking. OBJECTIVE: This study aimed to determine the effects of a prepregnancy weight loss intervention on gestational diabetes mellitus recurrence in women with overweight/obesity and previous gestational diabetes mellitus. STUDY DESIGN: A 2-site, randomized controlled trial comparing a prepregnancy lifestyle intervention with educational control was conducted between December 2017 and February 2022. A total of 199 English- and Spanish-speaking adults with overweight/obesity and previous gestational diabetes mellitus were randomized to a 16-week prepregnancy lifestyle intervention with ongoing treatment until conception or educational control. The primary outcome was gestational diabetes mellitus recurrence. Analyses excluded 6 participants who conceived but did not have gestational diabetes mellitus ascertained by standard methods. RESULTS: In the 63 (33%) women who conceived and had gestational diabetes mellitus ascertained (Ns=38/102 [37%] intervention vs 25/91 [28.0%] control; P=.17), those in the intervention group had significantly greater weight loss at 16 weeks compared with controls (4.8 [3.4-6.0] vs 0.7 [-0.9 to 2.3] kg; P=.001) and a greater proportion lost ≥5% of body weight (50.0% [17/34] vs 13.6% [3/22]; P=.005). There was no significant difference in the incidence of gestational diabetes mellitus recurrence between the intervention (57.9% [ns=23/38]) and the control group (44.0% [ns=11/25]; odds ratio, 1.8 [0.59-5.8]). Independent of group, greater prepregnancy weight loss predicted 21% lower odds of gestational diabetes mellitus recurrence (odds ratio, 0.79 [0.66-0.94]; P=.008). A ≥5% weight loss before conception reduced the odds of gestational diabetes mellitus recurrence by 82% (odds ratio, 0.18 [0.04-0.88]; P=.03). CONCLUSION: Lifestyle intervention produced considerable prepregnancy weight loss but did not affect gestational diabetes mellitus rates. Given that the conception rate was 50% lower than expected, this study was underpowered.

COVID-19 pandemic and stay-at-home mandates promote weight gain in US adults.

OBJECTIVE: The purpose of this study was to prospectively examine the effect of state stay-at-home mandates on weight of US adults by BMI over 3 months during COVID-19. METHODS: US adults completed an online questionnaire containing demographics, weight, physical activity, sedentary time, fruit/vegetable intake, depressive symptoms, stress, and sleep at baseline (May 2020) and after 3 months (August 2020). RESULTS: Participants gained 0.6 kg (76.7-77.3 kg, p = 0.002). A total of 26% of those with obesity gained > 2 kg compared with 14.8% of those with normal weight (p < 0.001). A total of 53.3% of individuals with obesity maintained weight within 2 kg compared with 72.5% of those with normal weight (p < 0.001). Greater weight gain was related to longer stay-at-home mandates (ß = 0.078, p = 0.010), lower baseline minutes of physical activity per day (ß = -0.107, p = 0.004), greater declines in minutes of physical activity per day (ß = -0.076, p = 0.026), depressive symptoms (ß = 0.098, p = 0.034), and greater increases in time preparing food (ß = 0.075, p = 0.031). CONCLUSIONS: US adults gained weight, and stay-at-home mandates were associated with atypical weight gain and greater reported weight gain in individuals with obesity over 3 months.

Protocol for a randomized controlled trial of pre-pregnancy lifestyle intervention to reduce recurrence of gestational diabetes: Gestational Diabetes Prevention/Prevención de la Diabetes Gestacional.

BACKGROUND: Gestational diabetes mellitus (GDM) is associated with several maternal complications in pregnancy, including preeclampsia, preterm labor, need for induction of labor, and cesarean delivery as well as increased long-term risks of type 2 diabetes, metabolic syndrome, and cardiovascular disease. Intrauterine exposure to GDM raises the risk for complications in offspring as well, including stillbirth, macrosomia, and birth trauma, and long-term risk of metabolic disease. One of the strongest risk factors for GDM is the occurrence of GDM in a prior pregnancy. Preliminary data from epidemiologic and bariatric surgery studies suggest that reducing body weight before pregnancy can prevent the development of GDM, but no adequately powered trial has tested the effects of a maternal lifestyle intervention before pregnancy to reduce body weight and prevent GDM recurrence. METHODS: The principal aim of the Gestational Diabetes Prevention/Prevención de la Diabetes Gestacional is to determine whether a lifestyle intervention to reduce body weight before pregnancy can reduce GDM recurrence. This two-site trial targets recruitment of 252 women with overweight and obesity who have previous histories of GDM and who plan to have another pregnancy in the next 1-3 years. Women are randomized within site to a comprehensive pre-pregnancy lifestyle intervention to promote weight loss with ongoing treatment until conception or an educational control group. Participants are assessed preconceptionally (at study entry, after 4 months, and at brief quarterly visits until conception), during pregnancy (at 26 weeks' gestation), and at 6 weeks postpartum. The primary outcome is GDM recurrence, and secondary outcomes include fasting glucose, biomarkers of cardiometabolic disease, prenatal and perinatal complications, and changes over time in weight, diet, physical activity, and psychosocial measures. DISCUSSION: The Gestational Diabetes Prevention /Prevención de la Diabetes Gestacional is the first randomized controlled trial to evaluate the effects of a lifestyle intervention delivered before pregnancy to prevent GDM recurrence. If found effective, the proposed lifestyle intervention could lay the groundwork for shifting current treatment practices towards the interconception period and provide evidence-based preconception counseling to optimize reproductive outcomes and prevent GDM and associated health risks. TRIAL REGISTRATION: ClinicalTrials.gov NCT02763150 . Registered on May 5, 2016.

Development and feasibility of randomized trial to reduce urinary bisphenols in women with obesity.

BACKGROUND: Bisphenol exposure is widespread and correlated with diabetes and cardiovascular disease. Previous intervention studies have successfully lowered bisphenol exposure among women of normal weight. The primary objective of this study was to develop and test the feasibility of a 3-week behavioral change intervention, rooted in social cognitive theory, to lower a broad range of bisphenols (BPA, BPS, and BPF) in women with obesity. METHODS: Thirty women with obesity (31.1 ± 5.6 kg/m2, 21.1 ± 3.1 years) were randomly assigned to an intervention or control. The intervention included weekly face-to-face meetings to reduce bisphenol exposures from food, cosmetics, and packaged products. Fasting urinary bisphenols, creatinine, and weight were assessed at study entry and after 3 weeks. RESULTS: The intervention was evaluated as feasible (100% of enrollment and recruitment, 96% of retention and attendance at lesson plan visits, and 96% of a collection of urine samples). Adherence to the intervention was estimated based on completion of self-monitoring records; the number of daily records completed was 7.7 ± 1.3 (mean ± SD) after week 1, 7.1 ± 1.5 after week 2, and 4.4 ± 0.9 after week 3. In secondary analysis, there was a significant treatment × time effect on creatinine-corrected urinary BPS (- 1.42 µg/g creatinine in the intervention vs. - 0.09 µg/g creatinine in the control group). CONCLUSION: In women with obesity, the 3-week intervention was considered feasible with promising preliminary results of decreasing BPS concentrations. These data warrant future large-scale clinical trial interventions to reduce bisphenol exposure and determine whether reductions in bisphenols positively impact diabetes and cardiovascular disease risk markers. This study was retroactively registered at ClinicalTrial.gov Identifier NCT03440307.

Rationale and design of a randomized controlled trial examining oral administration of bisphenol A on hepatic glucose production and skeletal muscle insulin sensitivity in adults.

Previous observational studies have shown that the endocrine disrupting chemical bisphenol A (BPA) is associated with type 2 diabetes, but few studies have examined direct effects of BPA on human health. The purpose of this study is to determine whether orally administered BPA at the US Environmental Protection Agency (EPA) safe dose of 50 µg/kg body weight has an adverse effect on hepatic glucose production and skeletal muscle insulin sensitivity. Forty, non-habitually active, healthy adults of normal weight will be enrolled. Participants will begin with a 2-day baseline energy balance diet low in bisphenols in which urine and blood will be collected, and standard tests performed to assess the primary outcome measures of hepatic glucose production (via [6,6-2H] glucose infusion) and skeletal muscle insulin sensitivity (via euglycemic hyperinsulinemic clamp technique). Secondary outcome measures are fasting hormones/endocrine factors (insulin, glucose, C-peptide, Pro-insulin, adiponectin, 17-beta-estradiol, free fatty acids) related to the pathogenesis of type 2 diabetes. Participants will then be randomly assigned to a 4-day energy balance diet plus oral administration of BPA at 50 µg/kg body weight (Diet + BPA) or 4-day energy balance diet plus oral administration of placebo (Diet + No BPA); all outcome measures will be reassessed after 4 days. Findings from this study will provide a framework for other studies in this area, and provide much needed experimental evidence using gold standard measures as to whether oral BPA administration over several days poses any risk of type 2 diabetes.

CLARITY-BPA Program in Rats: Is It Translatable to Humans?

The Consortium Linking Academic and Regulatory Insights on BPA Toxicity (CLARITY-BPA) program was the most comprehensive study to date examining a full range of health effects of varying bisphenol A (BPA) exposure in rats. The major concern of the CLARITY-BPA program that has not previously been discussed is whether exposing rats to varying doses to BPA is translatable to humans, even at the "typical" exposure ranges for humans. This perspective will provide evidence that the vast majority of pharmaceutical drug development and other trials in animals have not been replicated in human randomized studies. Similarly, to truly understand whether BPA exposure affects human health, clinical trials are needed to examine BPA administration in humans in controlled settings.

Ripple Effect of Lifestyle Interventions During Pregnancy on Untreated Partners' Weight.

OBJECTIVE: Weight-loss interventions have a positive "ripple effect" on untreated partners' weight, but ripple effects in pregnancy are unknown. The objective of this study was to determine whether prenatal lifestyle interventions that reduce gestational weight gain in pregnant women have a positive ripple effect on untreated partners' weight. METHODS: Two clinical trials with the same outcome measures randomly assigned pregnant women to a lifestyle intervention or usual care. Untreated partners were randomly assigned according to their pregnant partner's group allocation and were assessed at study entry (~13 weeks' gestation), 35 weeks' gestation, and 6 and 12 months after delivery. RESULTS: A total of 122 partners (100% male, 23% Hispanic, 82% married, and 48% with obesity) were randomly assigned to the intervention (n = 59) or usual care (n = 63). There was no intervention or intervention-by-time interaction effect on partner weight (P = 0.795). Partner weight changes were not statistically significant (P = 0.120) from study entry to 35 weeks' gestation (mean 0.19 kg; 95% CI: -0.73 to 1.24) or to 12 months after delivery (mean 0.82 kg; 95% CI: -0.26 to 1.91). CONCLUSIONS: There was no evidence of a ripple effect on partner weight. In a self-selected sample, partners of pregnant women appeared not to experience sympathy weight gain.

Pilot Study on the Effect of Orally Administered Bisphenol A on Glucose and Insulin Response in Nonobese Adults.

OBJECTIVE: To determine the effects of varying doses of orally administered BPA on indices of glucose metabolism. METHODS: Eleven college students (21.0 ± 0.8 years; 24.2 ± 3.9 kg/m2) were randomized in a double-blinded, crossover fashion separated by >1 week to placebo (PL), deuterated BPA at 4 µg/kg body weight (BPA-4), and deuterated BPA at 50 µg/kg body weight (BPA-50). Total BPA, glucose, insulin, and C-peptide were assessed at baseline, minutes 15, 30, 45, 60, and every 30 minutes for 2 hours in response to a glucose tolerance test. RESULTS: There was a significant condition × time interaction for total BPA (P < 0.001) such that BPA increased more rapidly in BPA-50 than BPA-4 and PL (P = 0.003) and increased more rapidly in BPA-4 than PL (P < 0.001). There were no significant condition × time interactions on glucose, insulin, and C-peptide. Significant condition main effects were observed for glucose such that BPA-50 was significantly lower than PL (P = 0.036) and nearly lower for BPA-4 vs PL (P = 0.056). Significant condition main effects were observed such that insulin in BPA-50 was lower than BPA-4 (P = 0.021), and C-peptide in BPA-50 was lower than BPA-4 (t18 = 3.95; Tukey-adjusted P = 0.003). Glucose, insulin, and C-peptide areas under the curve for the 3-hour profile were significantly lower in BPA-50 vs PL (P < 0.05). CONCLUSION: Orally administered BPA protocol appeared feasible and has immediate effects on glucose, insulin, and C-peptide concentrations.

Does Partial Meal Replacement During Pregnancy Reduce 12-Month Postpartum Weight Retention?

OBJECTIVE: This randomized trial tested whether a behavioral intervention with meal replacements in pregnancy could increase the proportion of women who returned to prepregnancy weight and reduce postpartum weight retention by 12 months after delivery. METHODS: Women (N = 264; 13.7 weeks' gestation) with overweight or obesity were randomly assigned to usual care or intervention. The intervention reduced excess gestational weight gain and was discontinued at delivery. At follow-up, 83.7% completed the 12-month assessment. RESULTS: Compared with usual care, prenatal intervention had no significant effect on odds of achieving prepregnancy weight (38/128 [29.7%] vs. 41/129 [31.8%]; P = 0.98) or in reducing the magnitude of weight retained (3.3 vs. 3.1 kg; P = 0.82) at 12 months. After delivery, significant (P < 0.0001) declines in meal replacements, practice of weight control behaviors, and dietary restraint were observed in the intervention group. Independent of group, lower gestational weight gain was the strongest predictor of achieving prepregnancy weight at 12 months (P = 0.0008). CONCLUSIONS: A prenatal behavioral intervention with meal replacements that reduced pregnancy weight gain had no significant effect on 12-month postpartum weight retention.

Randomized controlled clinical trial of behavioral lifestyle intervention with partial meal replacement to reduce excessive gestational weight gain.

Background: Behavioral lifestyle interventions during pregnancy can prevent excessive gestational weight gain (GWG) in women with normal weight; however, effective interventions to reduce GWG in ethnically diverse women with obesity are lacking. Objective: A randomized controlled trial was conducted to test whether a behavioral lifestyle intervention with partial meal replacement reduces GWG rate in Hispanic and non-Hispanic women with overweight or obesity relative to enhanced usual care. Design: Participants (n = 257) were recruited in San Luis Obispo, California, and Providence, Rhode Island, between November 2012 and May 2016. Participants were pregnant (mean ± SD: 13.6 ± 1.8 wk of gestation) with overweight or obesity and had a mean age of 30.3 y; 41.6% of participants were Hispanic. Women were randomly assigned within site and by ethnicity to enhanced usual care (n = 128) or to a behavioral lifestyle intervention with partial meal replacement (n = 129). The primary outcome was GWG per week of observation. Secondary outcomes were proportions exceeding Institute of Medicine (IOM) guidelines for total GWG, changes in weight-control behaviors and cardiovascular disease risk factors, and incidence of pregnancy complications. Study retention was 99.6% (256 of 257). Results: The intervention compared with usual care resulted in less mean ± SD weekly GWG (0.33 ± 0.25 compared with 0.39 ± 0.23 kg/wk; P = 0.02) and total GWG (9.4 ± 6.9 compared with 11.2 ± 7.0 kg; P = 0.03) and reduced the proportion of women who exceeded IOM guidelines for total GWG (41.1% compared with 53.9%; P = 0.03). No significant group × time × demographic subgroup (ethnicity, BMI, age, parity, and income) interactions were observed. Among intervention participants, greater meal replacement intake was related to reduced GWG rate (ß = -0.07; 95% CI:-0.12, -0.03; P = 0.002). The intervention compared with usual care increased weight-control strategies (P < 0.0001) and cognitive restraint (P < 0.0001) and reduced triglycerides (P = 0.03). Conclusion: Prenatal behavioral intervention with partial meal replacement significantly reduced GWG in Hispanic and non-Hispanic women with overweight or obesity. This trial was registered at www.clinicaltrials.gov as NCT01545934.

Acculturation Influences Postpartum Eating, Activity, and Weight Retention in Low-Income Hispanic Women.

BACKGROUND: Low-income Hispanic women experience elevated rates of high postpartum weight retention (PPWR), which is an independent risk factor for lifetime obesity. Sociocultural factors might play an important role among Hispanic women; however, very few studies have examined this association. OBJECTIVE: The purpose of our study was to examine the associations between acculturation and maternal diet, physical activity, and PPWR. DESIGN: This is a cross-sectional study of baseline data from 282 Hispanic women participating in the FitMoms/Mamás Activas study, a randomized controlled trial examining the impact of primarily an internet-based weight control program, in reducing PPWR among low-income women. We performed multivariable linear regression to examine the association of acculturation with diet quality, physical activity, and PPWR at study entry. RESULTS: A total of 213 (76%) women had acculturation scores reflecting Mexican orientation or bicultural orientation, whereas 69 (24%) had scores that represented assimilation to Anglo culture. Women who were more acculturated had lower intakes of fruits and vegetables, lower HEI scores, and lower physical activity levels than women who were less acculturated (p < 0.05). We found an association between acculturation and PPWR in that for every 1-unit increase in acculturation score, PPWR increased, on average, by 0.80 kg. CONCLUSION: Higher acculturation was associated with poorer diet and physical activity behaviors and greater PPWR.

Effect of an Internet-Based Program on Weight Loss for Low-Income Postpartum Women: A Randomized Clinical Trial.

Importance: Postpartum weight retention increases lifetime risk of obesity and related morbidity. Few effective interventions exist for multicultural, low-income women. Objective: To test whether an internet-based weight loss program in addition to the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC program) for low-income postpartum women could produce greater weight loss than the WIC program alone over 12 months. Design, Setting, and Participants: A 12-month, cluster randomized, assessor-blind, clinical trial enrolling 371 adult postpartum women at 12 clinics in WIC programs from the California central coast between July 2011 and May 2015 with data collection completed in May 2016. Interventions: Clinics were randomized to the WIC program (standard care group) or the WIC program plus a 12-month primarily internet-based weight loss program (intervention group), including a website with weekly lessons, web diary, instructional videos, computerized feedback, text messages, and monthly face-to-face groups at the WIC clinics. Main Outcomes and Measures: The primary outcome was weight change over 12 months, based on measurements at baseline, 6 months, and 12 months. Secondary outcomes included proportion returning to preconception weight and changes in physical activity and diet. Results: Participants included 371 women (mean age, 28.1 years; Hispanic, 81.6%; mean weight above prepregnancy weight, 7.8 kg; mean months post partum, 5.2 months) randomized to the intervention group (n = 174) or standard care group (n = 197); 89.2% of participants completed the study. The intervention group produced greater mean 12-month weight loss compared with the standard care group (3.2 kg in the intervention group vs 0.9 kg in standard care group, P < .001; difference, 2.3 kg (95% CI, 1.1 to 3.5). More participants in the intervention group than the standard care group returned to preconception weight by 12 months (32.8% in the intervention group vs 18.6% in the standard care group, P < .001; difference, 14.2 percentage points [95% CI, 4.7 to 23.5]). The intervention group and standard care group did not significantly differ in 12-month changes in physical activity (mean [95% CI]: -7.8 min/d [-16.1 to 0.4] in the intervention group vs -7.2 min/d [-14.6 to 0.3] in the standard care group; difference, -0.7 min/d [95% CI, -42.0 to 10.6], P = .76), calorie intake (mean [95% CI]: -298 kcal/d [-423 to -174] in the intervention group vs -144 kcal/d [-257 to -32] in the standard care group; difference, -154 kcal/d [-325 to 17], P = .06), or incidences of injury (16 in the intervention group vs 16 in the standard care group) or low breastmilk supply from baseline to month 6 (21 of 61 participants in the intervention group vs 23 of 72 participants in the standard care group) and from month 6 to 12 (13 of 32 participants in the intervention group vs 14 of 37 participants in the standard care group). Conclusions and Relevance: Among low-income postpartum women, an internet-based weight loss program in addition to the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC program) compared with the WIC program alone resulted in a statistically significant greater weight loss over 12 months. Further research is needed to determine program and cost-effectiveness as part of the WIC program. Trial Registration: clinicaltrials.gov Identifier: NCT01408147.

Randomized Intervention Trial to Decrease Bisphenol A Urine Concentrations in Women: Pilot Study.

BACKGROUND: Previous studies have shown that women have higher concentrations of the endocrine disruptor bisphenol A (BPA), but an intervention to reduce BPA is lacking in women. To test the hypothesis that an intervention to reduce BPA would decrease urinary BPA concentrations over 3 weeks, 24 women (mean ± standard deviation [SD]; 22.1 ± 2.8 kg/m2 body mass index, 20.9 ± 1.5 years) were randomly assigned to an intervention or control. MATERIALS AND METHODS: The intervention included weekly face-to-face meetings to reduce BPA exposures from food, cosmetics, and other packaged products. Women were provided with BPA-free cosmetics, hygiene, glass food/water containers, and daily self-monitored major sources of BPA. Fasting urine BPA and creatinine concentrations, and weight were assessed at study entry and after 3 weeks. RESULTS: A significant (p = 0.04) treatment × time interaction effect was observed on creatinine-adjusted BPA concentrations. From study entry to 3 weeks, women in the intervention significantly decreased geometric mean creatinine-adjusted urinary BPA by -0.71 ng/m, whereas women in the control significantly increased urinary BPA by 0.32 ng/mL (p = 0.04). Additionally, from study entry to 3 weeks, women in the intervention significantly lost weight -0.28 ± 0.44 kg, whereas women in the control significantly gained weight +1.65 ± 0.74 kg (p = 0.03). Changes in creatinine-adjusted BPA concentrations and weight were not significantly related (p = 0.67). CONCLUSION: In this pilot study, a 3-week intervention decreased urinary BPA concentrations in women. Future clinical trials are needed to confirm these results and to examine whether a similar BPA intervention positively impacts risk markers in the pathogenesis of cardiovascular disease and diabetes.

Effects of maternal lifestyle intervention during pregnancy on untreated partner weight: Results from fit for delivery study.

OBJECTIVE: To test the hypothesis that untreated partners of pregnant women receiving a prenatal lifestyle intervention (vs. standard care) would lose more weight during pregnancy and postpartum. METHODS: Fit for Delivery was a study of 401 pregnant women with overweight/obesity (OW/OB) and normal weight (NW) randomized to prenatal lifestyle intervention or standard care. Mother's self-report of partners' weight was obtained at study entry (<16 weeks gestation), 30 weeks gestation, and 6 and 12 months postpartum. RESULTS: At study entry, 157 of 200 (78%) of intervention mothers and 144 of 201 (72%) of standard care mothers reported having a partner. In intent-to-treat analyses, there was no significant treatment × time effects on partner weight (P = 0.67). In secondary analyses, partners of OW/OB intervention women lost weight from study entry to 6 and 12 months postpartum (-0.5 ± 9.5 kg, -1.0 ± 9.3 kg; P < 0.05), while partners of standard care women gained weight during the same time frame (+2.5 ± 6.7 kg, +2.9 ± 7.4 kg; P < 0.05); adjusting for partner study entry BMI removed these effects. CONCLUSIONS: Lifestyle intervention delivered to pregnant women did not significantly reduce weight of untreated partners. Future research is needed to test prenatal interventions that engage partners and use objective measures of weight.

Effects of acute exercise on appetite hormones and ad libitum energy intake in men and women.

Acute exercise suppresses relative energy intake; however, it remains unclear whether this occurs in both men and women exposed to the same relative exercise treatment. Eleven healthy men (22 ± 2 years; 16% ± 6% body fat (BF); 26 ± 4 body mass index (BMI); 42.9 ± 6.5 mL·kg(-1)·min(-1) peak oxygen consumption ([Formula: see text]O(2peak))) and 10 healthy women (21 ± 2 years; 24 ± 2 BMI; 23% ± 3% BF; 39.9 ± 5.5 mL·kg(-1)·min(-1) [Formula: see text]O(2peak)) rested for 60 min or exercised on a cycle ergometer at 70% [Formula: see text]O(2peak) until 30% of total daily energy expenditure was expended (men, expenditure = 975 ± 195 kcal in 82 ± 13 min; women, expenditure = 713 ± 86 kcal in 84 ± 17 min) in a counterbalanced, crossover fashion. Appetite hormones and appetite ratings were assessed in response to each condition. Forty minutes after both conditions, ad libitum total and relative energy intake (energy intake minus energy cost of exercise) were assessed at a buffet meal. There was no significant sex or condition effect in appetite hormones (PYY(3-36), acylated ghrelin, insulin) and appetite ratings (hunger, satisfaction, fullness). Total energy intake in men was significantly higher (P < 0.05) in exercise and rest conditions (1648 ± 950, 1216 ± 633 kcal, respectively) compared with women (591 ± 183, 590 ± 231 kcal, respectively). Relative energy intake was significantly lower (P < 0.05) after exercise compared with rest in men (672 ± 827, 1133 ± 619 kcal, respectively) and women (-121 ± 243, 530 ± 233 kcal, respectively). These data highlight the effectiveness of acute exercise to suppress relative energy intake regardless of sex.

Effects of combined creatine and sodium bicarbonate supplementation on repeated sprint performance in trained men.

Creatine and sodium bicarbonate supplementation independently increase exercise performance, but it remains unclear whether combining these 2 supplements is more beneficial on exercise performance. The purpose of this study was to evaluate the impact of combining creatine monohydrate and sodium bicarbonate supplementation on exercise performance. Thirteen healthy, trained men (21.1 ± 0.6 years, 23.5 ± 0.5 kg·m(-2), 66.7 ± 5.7 ml·(kg·m)(-1) completed 3 conditions in a double-blinded, crossover fashion: (a) Placebo (Pl; 20 g maltodextrin + 0.5 g·kg(-1) maltodextrin), (b) Creatine (Cr; 20 g + 0.5 g·kg(-1) maltodextrin), and (c) Creatine plus sodium bicarbonate (Cr + Sb; 20 g + 0.5 g·kg(-1) sodium bicarbonate). Each condition consisted of supplementation for 2 days followed by a 3-week washout. Peak power, mean power, relative peak power, and bicarbonate concentrations were assessed during six 10-second repeated Wingate sprint tests on a cycle ergometer with a 60-second rest period between each sprint. Compared with Pl, relative peak power was significantly higher in Cr (4%) and Cr + Sb (7%). Relative peak power was significantly lower in sprints 4-6, compared with that in sprint 1, in both Pl and Cr. However, in Cr + Sb, sprint 6 was the only sprint significantly lower compared with sprint 1. Pre-Wingate bicarbonate concentrations were significantly higher in Cr + Sb (10%), compared with in Pl and Cr, and mean concentrations remained higher after sprint 6, although not significantly. Combining creatine and sodium bicarbonate supplementation increased peak and mean power and had the greatest attenuation of decline in relative peak power over the 6 repeated sprints. These data suggest that combining these 2 supplements may be advantageous for athletes participating in high-intensity, intermittent exercise.

Aerobic exercise reduces neuronal responses in food reward brain regions.

Acute exercise suppresses ad libitum energy intake, but little is known about the effects of exercise on food reward brain regions. After an overnight fast, 30 (17 men, 13 women), healthy, habitually active (age = 22.2 ± 0.7 yr, body mass index = 23.6 ± 0.4 kg/m(2), Vo(2peak) = 44.2 ± 1.5 ml·kg(-1)·min(-1)) individuals completed 60 min of exercise on a cycle ergometer or 60 min of rest (no-exercise) in a counterbalanced, crossover fashion. After each condition, blood oxygen level-dependent responses to high-energy food, low-energy food, and control visual cues, were measured by functional magnetic resonance imaging. Exercise, compared with no-exercise, significantly (P < 0.005) reduced the neuronal response to food (high and low food) cues vs. control cues in the insula (-0.37 ± 0.13 vs. +0.07 ± 0.18%), putamen (-0.39 ± 0.10 vs. -0.10 ± 0.09%), and rolandic operculum (-0.37 ± 0.17 vs. 0.17 ± 0.12%). Exercise alone significantly (P < 0.005) reduced the neuronal response to high food vs. control and low food vs. control cues in the inferior orbitofrontal cortex (-0.94 ± 0.33%), insula (-0.37 ± 0.13%), and putamen (-0.41 ± 0.10%). No-exercise alone significantly (P < 0.005) reduced the neuronal response to high vs. control and low vs. control cues in the middle (-0.47 ± 0.15%) and inferior occipital gyrus (-1.00 ± 0.23%). Exercise reduced neuronal responses in brain regions consistent with reduced pleasure of food, reduced incentive motivation to eat, and reduced anticipation and consumption of food. Reduced neuronal response in these food reward brain regions after exercise is in line with the paradigm that acute exercise suppresses subsequent energy intake.

Reducing excessive gestational weight gain: lessons from the weight control literature and avenues for future research.

Excessive gestational weight gain is a prevalent problem and an independent predictor of future obesity in both mothers and offspring. Intervention research to prevent excessive gestational weight gain is still in its infancy but results to date have been quite modest. Research in weight control outside of pregnancy over the past 30 years has been more robust and identified several key components of effective programs, including use of caloric restriction, daily diet self-monitoring, self-weighing, behavior therapy and ongoing patient-provider contact. The aim of this article is to summarize intervention components shown to be effective in promoting successful weight control outside of pregnancy and explore potential applications in pregnancy. Available evidence suggests that the strategies shown to be effective for weight control outside of pregnancy may also promote better weight control in pregnancy, but several lines for future investigation remain.

Metformin's effect on exercise and postexercise substrate oxidation.

Exercise and metformin may prevent or delay Type 2 diabetes by, in part, raising the capacity for fat oxidation. Whether the addition of metformin has additive effects on fat oxidation during and after exercise is unknown. Therefore, the purpose of this study was to evaluate the effect of metformin on substrate oxidation during and after exercise. Using a double-blind, counter-balanced crossover design, substrate oxidation was assessed by indirect calorimetry in 15 individuals taking metformin (2,000 mg/d) and placebo for 8-10 d. Measurements were made during cycle exercise at 5 submaximal cycle workloads, starting at 30% peak work (W(peak)) and increasing by 10% every 8 min to 70% W(peak). Substrate oxidation was also measured for 50 min postexercise. Differences between conditions were assessed using analysis of variance with repeated measures, and values are reported as M + or - SE. During exercise, fat oxidation (0.19 + or - 0.03 vs. 0.15 + or - 0.01 g/min, p < .01) and percentage of energy from fat (32% + or - 3% vs. 28% + or - 3%, p < .01) were higher with metformin than with placebo. Postexercise, metformin slightly lowered fat oxidation (0.12 + or - 0.02 to 0.10 + or - 0.02 g/min, p < .01) compared with placebo. There was an inverse relationship between postexercise fat oxidation and the rate of fat oxidation during exercise (r = -.68, p < .05). In healthy individuals, metformin has opposing actions on fat oxidation during and after exercise. Whether the same effects are evident in insulin-resistant individuals remains to be determined.