Higher baseline resting metabolic rate is associated with 1-year frailty decline among older adults residing in an urban area.

BACKGROUND: Dysregulated energy metabolism is one hypothesized mechanism underlying frailty. Resting energy expenditure, as reflected by resting metabolic rate (RMR), makes up the largest component of total energy expenditure. Prior work relating RMR to frailty has largely been done in cross section with mixed results. We investigated whether and how RMR related to 1-year frailty change while adjusting for body composition. METHODS: N = 116 urban, predominantly African-American older adults were recruited between 2011 and 2019. One-year frailty phenotype (0-5) was regressed on baseline RMR, frailty phenotype, demographics and body composition (DEXA) in an ordinal logistic regression model. Multimorbidity (Charlson comorbidity scale, polypharmacy) and cognitive function (Montreal Cognitive Assessment) were separately added to the model to assess for change to the RMR-frailty relationship. The model was then stratified by baseline frailty status (non-frail, pre-frail) to explore differential RMR effects across frailty. RESULTS: Higher baseline RMR was associated with worse 1-year frailty (odds ratio = 1.006 for each kcal/day, p = 0.001) independent of baseline frailty, demographics, and body composition. Lower fat-free mass (odds ratio = 0.88 per kg mass, p = 0.008) was independently associated with worse 1-year frailty scores. Neither multimorbidity nor cognitive function altered these relationships. The associations between worse 1-year frailty and higher baseline RMR (odds ratio = 1.009, p < 0.001) and lower baseline fat-free mass (odds ratio = 0.81, p = 0.006) were strongest among those who were pre-frail at baseline. DISCUSSION: We are among the first to relate RMR to 1-year change in frailty scores. Those with higher baseline RMR and lower fat-free mass had worse 1-year frailty scores, but these relationships were strongest among adults who were pre-frail at baseline. These relationships were not explained by chronic disease or impaired cognition. These results provide new evidence suggesting higher resting energy expenditure is associated with accelerate frailty decline.

Vaginal prevalence of human papillomavirus infections in women with uterovaginal aplasia before and after laparoscopically assisted creation of a neovagina: a prospective epidemiological observational study.

OBJECTIVE: To study vaginal as opposed to cervical human papillomavirus (HPV) acquisition with regard to true prevalence, HPV types, and the role of co-factors in virgins and after their sexual debut. DESIGN: Prospective epidemiological observational study. SETTING: University hospital specialised in genital malformations. POPULATION: Women diagnosed with Mayer-Rokitansky-Küster-Hauser syndrome (MRKHS) and undergoing neovaginoplasty between November 2011 and July 2017. METHODS: This is a prospective study including 186 women with MRKHS before and after sexual debut. MAIN OUTCOME MEASURES: Conventional vaginal cytology and different HPV tests were performed at surgery and during routine gynaecological follow-up 1, 3, 6 and ≥ 11 months after surgery and risk factors were documented. RESULTS: The mean age of all women at surgery was 20.1 years (SD 5.4), mean body mass index (BMI) was 22.1 kg/m2 (SD 4.6). In 83 vaginal samples from 41 different women at least one of the HPV tests was positive. Thirty-three different HPV types were detected. The prevalence of 41/186 = 22.0% as well as type distribution are comparable with those found in a young German female population. The overall rate of acquisition was clearly associated with sexual activity and smoking habits. Out of 367 Papanicolaou smears only six were abnormal with Pap IIID (MN II) and no obvious vaginal lesion was detected. CONCLUSIONS: Vaginal HPV prevalence and HPV types in previously virgin women after creation of a neovagina are not different from the acquisition of cervical infections in the general population and is clearly associated with sexual activity and with smoking habits. However, abnormal Papanicolaou smears are rarely seen. TWEETABLE ABSTRACT: Vaginal HPV prevalence after creation of a neovagina is similar to that on the cervix in the general population.

Energy balance measurement: when something is not better than nothing.

Energy intake (EI) and physical activity energy expenditure (PAEE) are key modifiable determinants of energy balance, traditionally assessed by self-report despite its repeated demonstration of considerable inaccuracies. We argue here that it is time to move from the common view that self-reports of EI and PAEE are imperfect, but nevertheless deserving of use, to a view commensurate with the evidence that self-reports of EI and PAEE are so poor that they are wholly unacceptable for scientific research on EI and PAEE. While new strategies for objectively determining energy balance are in their infancy, it is unacceptable to use decidedly inaccurate instruments, which may misguide health-care policies, future research and clinical judgment. The scientific and medical communities should discontinue reliance on self-reported EI and PAEE. Researchers and sponsors should develop objective measures of energy balance.

Breath carbon stable isotope ratios identify changes in energy balance and substrate utilization in humans.

Rapid detection of shifts in substrate utilization and energy balance would provide a compelling biofeedback tool for individuals attempting weight loss. As a proof of concept, we tested whether the natural abundance of exhaled carbon stable isotope ratios (breath δ(13)C) reflects shifts between negative and positive energy balance. Volunteers (n=5) consumed a 40% energy-restricted diet for 6 days followed by 50% excess on day 7. Breath was sampled immediately before and 1 h and 2 h after breakfast, lunch and dinner. Exhaled breath δ(13)C values were measured by cavity ring-down spectroscopy. Using repeated measures analysis of variance (ANOVA) followed by Dunnett's contrasts, pre-breakfast breath values on days 2-6 were compared with day 1, and postprandial day 7 time points were compared with pre-breakfast day 7. Energy restriction diminished pre-breakfast breath δ(13)C by day 3 (P<0.05). On day 7, increased energy intake was first detected immediately before dinner (-23.8±0.6 vs -21.9±0.7‰, P=0.002 (means±s.d.)), and breath δ(13)C remained elevated at least 2 h post dinner. In conclusion, when shifting between negative and positive energy balance, breath δ(13)C showed anticipated isotopic changes. Although additional research is needed to determine specificity and repeatability, this method may provide a biomarker for marked increases in caloric intake.

Effect of clothing weight on body weight.

BACKGROUND: In clinical settings, it is common to measure weight of clothed patients and estimate a correction for the weight of clothing, but we can find no papers in the medical literature regarding the variability in clothing weight of adults with weather, season and gender. METHODS: Fifty adults (35 women) were weighed four times during a 12-month period with and without clothing. Clothing weights were determined and regressed against minimum, maximum and average daily outdoor temperature. RESULTS: The average clothing weight (±s.d.) throughout the year was significantly greater in men than in women (1.2±0.3 vs 0.8±0.3 kg, P<0.0001). The average within-person minimum and the average within-person maximum clothing weights across the year were 0.9±0.2 and 1.5±0.4 kg for men, and 0.5±0.2 and 1.1±0.4 kg for women, respectively. The within-person s.d. in clothing weight was 0.3 kg for both men and women. Over the 55 °C range in the lowest to the highest outdoor temperatures, the regressions predicted a maximal change in clothing weight of only 0.4 kg in women and 0.6 kg in men. CONCLUSION: The clothing weight of men is significantly greater than that of women, but there is little variability throughout the year. Therefore, a clothing adjustment of approximately 0.8 kg for women and 1.2 kg for men is appropriate regardless of outdoor temperature.

Effect of exercise on the diurnal variation in energy substrate use during a high-fat diet.

Aerobic exercise increases 24-h fat oxidation following initiation of a high-fat diet. The objective of this study is to examine the time course of increased fat oxidation under exercise and sedentary conditions. Eighteen healthy subjects completed a randomized crossover design (sedentary and exercise visits) staying for five consecutive days in a metabolic chamber each visit. On day 1, 30% of energy intake was from fat; days 2-5 had 50% of energy as fat. During exercise, subjects rode on a stationary cycle at 45% of VO2max for 1 h in the mornings and evenings. Respiratory gases and urinary nitrogen were collected to calculate macronutrient oxidation and non-protein respiratory exchange ratio (NPRER). This data, collected continuously (24-h periods), were subsequently divided into three time segments: (1) exercise + recovery (1000-1200 hours, 2100-2200 hours), (2) sleep (2300-0645 hours), and (3) wake (all remaining hours). NPRER on exercise versus sedentary visits was lower for the sleep segment (0.77 ± 0.01 01 vs. 0.81 ± 0.01, p < 0.001), higher for the exercise + recovery segment (0.88 ± 0.01 vs. 0.86 ± 0.01, p < 0.001), and was not different for the wake segment. Fat oxidation was significantly higher for exercise versus sedentary treatments during sleep (41 ± 2 vs. 31 ± 2 g), wake (62 ± 3 vs. 51 ± 3 g), and exercise + recovery segments (33 ± 3 vs.16 ± 1 g), but so was fat intake by design (171 ± 8 vs. 128 ± 7 g/d). Although exercise showed greater fat oxidation during all segments, dietary fat intake was also higher. Therefore, based on NPRER, the time of day during which the exercise treatment increased the ratio of fat to carbohydrate oxidation was during sleep.

Impact of exercise and dietary fatty acid composition from a high-fat diet on markers of hunger and satiety.

To compare the effects of both dietary fatty acid composition and exercise vs. sedentary conditions on circulating levels of hunger and satiety hormones. Eight healthy males were randomized in a 2 × 2 crossover design. The four treatments were 3 days of HF diets (50% of energy) containing high saturated fat (22% of energy) with exercise (SE) or sedentary (SS) conditions, and high monounsaturated fat (30% of energy) with exercise (UE) or sedentary (US) conditions. Cycling exercise was completed at 45% of VO(2)max for 2h daily. On the third HF day, 20 blood samples were drawn over a 24h period for each hormone (leptin, insulin, ghrelin, and peptide YY (PYY)). A visual analog scale (VAS) was completed hourly between 0800 and 2200. Average 24h leptin and insulin levels were lower while 24h PYY was higher during exercise vs. sedentary conditions. FA composition did not differentially affect 24h hormone values. VAS scores for hunger and fullness did not differ between any treatment but did correlate with ghrelin, leptin, and insulin. High saturated or unsaturated fat diets did not differ with respect to markers of hunger or satiety. Exercise decreased 24h leptin and insulin while increasing PYY regardless of FA composition.

Insights into energy balance from doubly labeled water.

Obesity is defined as the excess storage of energy in the form of fat that results from imbalances between energy intake and expenditure. The study of the components of energy balance has undergone a significant advancement with the application of the doubly labeled water (DLW) method to the measurement of human energy expenditure. This manuscript includes a selective review of the studies that have utilized the doubly labeled method as it applies to the study of human obesity. Although generally now accepted, one of the major surprises from the early applications of DLW was that obese individuals have higher energy expenditures than lean controls. Moreover, weight gain, even in the already obese, is associated with an increase in energy expenditure as weight is one of the strongest predictors of total energy expenditure. Similarly, studies of weight loss treatment show a decrease in energy expenditure due to weight loss and due to adaptive changes in energetic efficiency, but these changes do not account for the common cessation of weight loss observed after 12-26 weeks of restriction. The accumulating data from the application of the DLW method suggest a need to place greater emphasis on mechanisms that lead to a mismatch between energy intake and expenditure rather than a continuing emphasis on energy intake or energy expenditure alone.

Circannual variation in relative weight of children 5 to 16 years of age.

BACKGROUND: Summer weight gain in children has been reported; however, this is usually based on two time points. Our objective was to investigate monthly variation in weight status. METHODS: Cross-sectional, de-identified health records including height, weight and demographics, collected between 2007 and 2012 from South Central Wisconsin in 70 531 children age 5-16 years were analysed. The monthly averages in body mass index (BMI) z-score were analysed cross-sectionally followed by a paired analysis for a subset with one visit each during school and summer months. RESULTS: BMI z-scores during the summer months (June-August) were lower than values during the school year (September-May). Of note, there was a rapid decrease in BMI z-scores from May to June, with June BMI z-score values being 0.065 units less (95% CI 0.046-0.085) than those in May, little change from June to August and a rapid increase between the August and September BMI z-scores. CONCLUSION: The monthly pattern does not fully agree with previous two-point school-based studies. Results raise concern that the use of two time point measures of BMIs (early fall and late spring) is suboptimal for evaluation of circannual variation. We suggest that future evaluation of the effect of school-based or summer interventions utilizes additional measures in those periods so that a seasonal analysis can be performed.

Entrainment of the diurnal rhythm of plasma leptin to meal timing.

To identify the physiologic factor(s) that entrain the diurnal rhythm of plasma leptin, leptin levels were measured hourly after changes in light/dark cycle, sleep/wake cycle, and meal timing. Four young male subjects were studied during each of two protocols, those being a simulated 12-h time zone shift and a 6.5-h meal shift. During the baseline day, plasma leptin demonstrated a strong diurnal rhythm with an amplitude of 21%, zenith at 2400 h, and nadir between 0900 and 1200 h. Acute sleep deprivation did not alter plasma leptin, but day/night reversal (time zone shift) caused a 12+/-2 h shift (P < 0.01) in the timing of the zenith and nadir. When meals were shifted 6.5 h without changing the light or sleep cycles, the plasma leptin rhythm was shifted by 5-7 h (P < 0.01). The phase change occurred rapidly when compared with changes in the diurnal rhythm of cortisol, suggesting that leptin levels are not acutely entrained to the circadian clock. The leptin rhythm was altered by meal timing in a manner very similar to the rhythm of de novo cholesterol synthesis. We conclude that the diurnal rhythm of plasma leptin in young males is entrained to meal timing.

Activity, adiposity and weight change in Jamaican adults.

OBJECTIVE: Populations in developing countries are particularly vulnerable to the development of obesity in the period of rapid transition to a more modernized lifestyle. We sought to determine the relationship between activity energy expenditure (AEE), adiposity and weight change in an adult population undergoing rapid socio-economic transition. METHODS: Total daily energy expenditure (TDEE) was measured using the doubly labelled water method, resting energy expenditure (REE) using indirect calorimetry and AEE calculated as the difference between TDEE and REE, in adults from a working class community in Spanish Town, Jamaica. During six years of follow-up, weight was measured between one and four times. Mixed effects regression modelling was used to test for association between components of the energy budget and weight change. RESULTS: Men (n = 17) weighed more but women (n = 18), had significantly more body fat, 38.5% vs 24.5%, respectively (p < 0.01). Men had higher levels of EE, particularly AEE after adjustment for body weight, 66.3 versus 46.4 kJ/kg.d for men and women, respectively (p < 0.001). At baseline, adjusted AEE was inversely associated with body fat in men and women, r = -0.46 and r = -0.48, respectively (p < 0.05). Mean rate of weight change was + 1.1 and + 1.2 kg/year for men and women, respectively. No component of EE, ie TDEE, REE or AEE, significantly predicted weight change in this small sample. CONCLUSIONS: These results suggest an important role for AEE in maintaining low levels of adiposity. The lack of association between EE and weight change, however, suggests populations in transition are at risk of obesity from environmental factors (eg dietary) other than simply declining physical activity levels.

Familial and individual predictors of obesity and insulin resistance in urban Hispanic children.

BACKGROUND: High intake of sugar-sweetened beverages (SSB) has been suggested to contribute to the pediatric obesity epidemic, however, how the home food environment influence children's intake of SSB among Hispanic families is still poorly understood. OBJECTIVES: To evaluate the relationships between the home food environment and Hispanic children's diet in relation to weight status and insulin resistance (IR). METHODS: A food frequency questionnaire was administered to 187 Hispanic children (ages 10 to 14 years) and anthropometrics were measured. IR was estimated from fasting insulin and glucose levels using the homeostasis model assessment of insulin resistance (HOMAIR ). Parents reported on family demographics and the home food environment. A structural equation modelling approach was applied to examine the hypothesized relationships among variables. RESULTS: The prevalence of childhood overweight and obesity was 52.8% and it was positively associated with HOMAIR (ß = 0.687, P < .0001). Children's SSB consumption was positively associated with children's body mass index z-score (ß = 0.151, P < 0.05) and subsequently to HOMAIR . Children's SSB consumption was predicted by home availability (ß = 0.191) and parental intake of SSB (ß = 0.419) (P < 0.05). The model fit indices [χ(2) = 45.821 (d.f. = 30, P > 0.01 and < 0.05), χ(2) /d.f. = 1.53, root mean square error of approximation = 0.053 (90% confidence interval = 0.016, 0.082), comparative fit index = 0.904] suggested a satisfactory goodness-of-fit. CONCLUSIONS: The home food environment and parental diet seem to play an important role in the children's access to and intake of SSB, which in turn predicted children's weight status.

High energy expenditure is not protective against increased adiposity in children.

BACKGROUND: Low levels of energy expenditure (TEE) may contribute to excess weight during childhood, but limited longitudinal data exist. OBJECTIVES: This is to test whether low TEE during the first 6 years of life could predict excess weight status at 8 years. METHODS: Total energy expenditure from doubly labelled water, weight, stature, waist circumference and fat mass and fat-free mass (FFM) in children at 0.25, 2, 4 and 6 years of age. This cohort includes individuals at high (n = 27) and low risk (n = 26) for childhood obesity, based upon whether pre-pregnant maternal obesity. A linear mixed effects model was fit to TEE. Individual variation was accounted for as a random effect. Residual TEE was calculated for age and individually averaged across time. RESULTS: Fat-free mass (kg) was highly correlated (R2 = 0.91) with TEE (kcal/day), and waist circumference and sex were also significant predictors of TEE. TEE residual tracked within individuals. TEE residuals did not correlate with either BMI or %fat at age 8 years. CONCLUSION: Using the residual TEE approach to identify high and low TEE during the first 6 years of life did not explain excess weight at 8 years of life in this cohort of children at high and low risk of obesity based upon maternal obesity status.

Relationship between blood pressure and physical activity assessed with stable isotopes.

Intrapopulation and interpopulation variation in blood pressure (BP) often reflects the joint effect of a complex set of risk factors, including lifestyle factors such as physical activity, diet, smoking and alcohol use. In this study, we set out to quantify the impact of habitual levels of physical activity on BP within and between three populations at contrasting levels of population risk of hypertension. Individuals were randomly sampled from communities in Nigeria (n=57), Jamaica (from Kingston, n=35) and the United States (from the Chicago area, n=32). Activity energy expenditure (AEE) (estimated from resting energy expenditure measured by indirect calorimetry and total expenditure measured with doubly labelled water) was used as an objective estimate of physical activity. In each of the three samples, there was a consistent negative correlation between BP and AEE. This negative association persisted after adjustment for age, sex and body fat (body mass index or percent fat mass). In multivariate models, adiposity was no longer a significant predictor of BP after accounting for low AEE. In conclusion these data suggest that habitual levels of physical activity may have a generalizable relationship with BP in populations with widely different social and environmental characteristics.

Association between apolipoprotein E phenotype and endogenous cholesterol synthesis as measured by deuterium uptake.

STUDY OBJECTIVE: The aim was to determine if central pool cholesterol formation rate is related to apo E phenotype in healthy normolipidaemic males. DESIGN: Subjects consumed a fixed composition diet for 5 d and at 07:00 hours on d 5 drank 0.7 g deuterium oxide (D2O).kg-1 body water. Over d 5 body water deuterium enrichment was maintained by ingestion of labelled drinking water. The fractional synthetic rate of the central pool free cholesterol was determined over two consecutive 12 h intervals by the incorporation of deuterium from body water into plasma unesterified cholesterol. SUBJECTS: Participants were healthy male volunteers, mean age 26.4 years. They were divided into E2/(2 or 3) and E4/(4 or 3) alleles, n = 9 in each group. MEASUREMENTS AND MAIN RESULTS: Subjects with E2/- showed lower fractional synthetic rates than E4/- subjects, at 0.070(SEM 0.007) v 0.097(0.009) d-1 over the 24 h period (p less than 0.05). Cholesterol fractional synthetic rate was higher during the night than during the day (p less than 0.05). CONCLUSIONS: These findings suggest an increased central pool free cholesterol synthesis in individuals possessing the apo epsilon-4 versus epsilon-2 allele. Apo E related regulation of whole body de novo cholesterol synthesis may therefore contribute to observed variations in plasma cholesterol levels.

The Association between Screen Time and Weight Status in Hispanic Children.

BACKGROUND: About one-third of U.S. children are overweight or obese and the number is even higher among Hispanics children (41%). In this regards, the time spent in sedentary behaviours is higher among Hispanic children versus non-Hispanic white children. But whether the home environment contributes to the obesity disparity among Hispanic children through the promotion of sedentary behaviours at home is less known. We aimed to investigate the associations between the home environment, parental limiting, and screen time with Hispanic children's body weight. METHODS: Study participants were middle school Hispanic children (n=187), ages 10-14 years and their parents. Children's anthropometrics were measured and used to calculate BMI z-scores. Questionnaires were used to assess children's time spent on physical activity (PA), sedentary activities, and to query parents on the home environment and parental limiting. RESULTS: Total time (h/d) spent watching television (TV) was positively associated with children's BMI z-score (P=0.02). However, no association was found between total screen time (TV, video games, and computer) and PA and with children's BMI z-score. Sleeping time (h/d) was inversely associated with children's BMI z-score (P=0.02); while there was a significant interaction between sleeping time and gender (P-interaction=0.02). Further, having a screen in the bedroom was positively associated with children's TV and total screen time (P<0.05); while parental limits on screen time was inversely associated with children's screen time (P<0.05). CONCLUSIONS: Screen and sleep time may contribute to higher body weight among Hispanic children, independently of associations with physical activity. Our findings suggest a differential effect of gender in the contribution of sleep time to higher body weight, in that girls spent less time sleeping when compared to boys. These findings can inform obesity-prevention efforts to intervene at the family level in improving sleeping patterns and increasing physical activity while reducing sedentary opportunities at home.

Assessing Children's Time-Use in Relation to Physical Fitness and Risks of Obesity and Diabetes: Development of a New Physical Activity Self-Report Instrument.

BACKGROUND: This study introduces a novel self-report instrument to measure children's time-use in physical and sedentary activities and examines the relationships between children's time-use and physical fitness and risks of obesity and diabetes. METHODS: The new instrument utilizes a series of timelines, each representing an activity type. 188 children (53% girls) aged 10 to 14 year-old participated in the study. Their time-use data for two weekdays and one weekend day were collected. Anthropometrics and cardiovascular fitness were measured and children's BMI z-score and PACER z-score were computed. One-time blood draw for fasting glucose and insulin were used to calculate insulin resistance using homeostasis model assessment for insulin resistance (HOMAIR). RESULTS: The reliability assessment of this instrument indicated a moderately reproducible procedure (ICC > 0.6) for six activity types. The validity correlation for motorized travel time was high (r = 0.226, P < 0.05) between self-report instrument and GPS tracks. PACER z-score was positively correlated with time-uses of play (r = 0.159, P < 0.05), and organized sports (r = 0.198, P < 0.05); and was highly inversely correlated with BMI z-score (r = -0.441, P < 0.0001) and HOMAIR (r = -0.472, P < 0.0001). Overall, only 14% of the children had physical activity for more than 60 minutes daily over three observation days. CONCLUSIONS: This instrument is particularly useful in assessing children's activity patterns, especially for specific physical activities. The new instrument provides a reproducible measure of children's perception of their activities. Our results emphasize the temporal context which is critical to formulating effective interventions targeting physical activity increase in children. Further efforts are needed to understand the differences between activity time obtained by the new self-report instrument and GPS tracks.

Twenty-four-hour leptin levels respond to cumulative short-term energy imbalance and predict subsequent intake.

Leptin plays a vital role in the regulation of energy balance in rodent models of obesity. However, less information is available about its homeostatic role in humans. The aim of this study was to determine whether leptin serves as an indicator of short-term energy balance by measuring acute effects of small manipulations in energy intake on leptin levels in normal individuals. The 12-day study was composed of four consecutive dietary-treatment periods of 3 days each. Baseline (BASE) [100% total energy expenditure (TEE)] feeding, followed by random crossover periods of overfeeding (130% TEE) or underfeeding (70% TEE) separated by a eucaloric (100% TEE) washout (WASH) period. The study participants were six healthy, nonobese subjects. Leptin levels serially measured throughout the study period allowed a daily profile for each treatment period to be constructed and a 24-h average to be calculated; ad libitum intake during breakfast "buffet" following each treatment period was also measured. Average changes in mesor leptin levels during WASH, which were sensitive to energy balance effected during the prior period, were observed. After underfeeding, leptin levels during WASH were 88 +/- 16% of those during BASE compared with 135 +/- 22% following overfeeding (P = 0.03). Leptin levels did not return to BASE during WASH when intake returned to 100% TEE, but instead were restored (104 +/- 21% and 106 +/- 16%; not significant) only after subjects crossed-over to complementary dietary treatment that restored cumulative energy balance. Changes in ad libitum intake from BASE correlated with changes in leptin levels (r2 = 0.40; P = 0.01). Leptin levels are acutely responsive to modest changes in energy balance. Because leptin levels returned to BASE only after completion of a complementary feeding period and restoration of cumulative energy balance, leptin levels reflect short-term cumulative energy balance. Leptin seems to maintain cumulative energy balance by modulating energy intake.

How much physical activity is enough to prevent unhealthy weight gain? Outcome of the IASO 1st Stock Conference and consensus statement.

A consensus meeting was held in Bangkok, 21-23 May 2002, where experts and young scientists in the field of physical activity, energy expenditure and body-weight regulation discussed the different aspects of physical activity in relation to the emerging problem of obesity worldwide. The following consensus statement was accepted unanimously. 'The current physical activity guideline for adults of 30 minutes of moderate intensity activity daily, preferably all days of the week, is of importance for limiting health risks for a number of chronic diseases including coronary heart disease and diabetes. However for preventing weight gain or regain this guideline is likely to be insufficient for many individuals in the current environment. There is compelling evidence that prevention of weight regain in formerly obese individuals requires 60-90 minutes of moderate intensity activity or lesser amounts of vigorous intensity activity. Although definitive data are lacking, it seems likely that moderate intensity activity of approximately 45 to 60 minutes per day, or 1.7 PAL (Physical Activity Level) is required to prevent the transition to overweight or obesity. For children, even more activity time is recommended. A good approach for many individuals to obtain the recommended level of physical activity is to reduce sedentary behaviour by incorporating more incidental and leisure-time activity into the daily routine. Political action is imperative to effect physical and social environmental changes to enable and encourage physical activity. Settings in which these environmental changes can be implemented include the urban and transportation infrastructure, schools, and workplaces.'