Closing the energy gap to prevent weight gain in China

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1 obr_0 obesity reviews Closing the energy gap to prevent weight gain in China F. Zhai,H.Wang,Z.Wang, B. M. Popkin and C. Chen 0 National Institute of Nutrition and Food Safety, Chinese Center f Disease Control and Prevention, Beijing, China; Carolina Population Center, University of Nth Carolina, Chapel Hill, NC, USA; Chinese Center f Disease Control and Prevention, Beijing, China Received ; revised ; accepted Address f crespondence: F Zhai, National Institute of Nutrition and Food Safety, Chinese Center f Disease Control and Prevention, no. Nanwei Road, Beijing 0000, China. zhai@infh.ac.cn Summary Xxxxxxxxxxxxxxxxxx Keywds: Energy gap, obesity, prevention. obesity reviews (0) (Suppl. ), 0 0 Introduction China is one of the most rapidly developing countries in the wld. Over the past years, the annual growth rate of the gross domestic product (GDP) has been me than % the highest rate in recent wld histy (). Many studies of the nutrition transition in China have documented that the food consumption pattern of Chinese has been shifting away from the traditional pattern characterized by the consumption of rice, wheat and wheat products towards high animal food consumption ( ). At the same time, inactivity (e.g. television use) is increasing (,,). Yet in 0,.% of pre-school children were still stunted (), but at the same time, the prevalence of overweight and obesity has risen to a high degree, and reached.% f the overall adult population by 0 (0,). Hill et al. () have proposed a way to estimate the degree of positive energy balance causing weight gain in a population, and have termed this the energy gap. Quantifying the energy gap is useful, because it can provide a quantitative estimate of the degree of behaviour change required to close the energy gap and thus prevent weight gain. The aim of this study was to use data from a longitudinal survey in China (CHNS) to provide a quantitative goal f the amount of energy balance change required to prevent excessive weight gain in the Chinese population. Methods Survey design and study population The CHNS is a longitudinal survey of health and nutrition in China, conducted jointly by the National Institute of Nutrition and Food Safety, the China Center f Disease Control, and the University of Nth Carolina at Chapel Hill. The survey began in and included eight provinces. Follow-up surveys were conducted in,,, 00 and 0 in the same eight provinces. In this analysis, we focused on a coht of adults (aged years in ) who had their weight measured in both the and 00 surveys The Auths Journal compilation 0 The International Association f the Study of Obesity. obesity reviews (Suppl. ), 0

2 obr_0 obesity reviews The energy gap in China F. Zhai et al. 0 0 Calculating the energy gap The energy gap was estimated accding to the method used by Hill et al. (). It was assumed that each kilogram of body-weight gain reflected a body energy accumulation of 00 kcal. Further, it was assumed that each kilogram of weight was sted in the body with 0% efficiency. By determining the weight change in this coht from to 00, we estimated the energy gap producing weight gain in the sample population. Results Participant characteristics The coht was composed of.% females and.% lived in rural areas. The age distribution in was.% between and years,.% between and 0 years, and.% between 0 and years. Changes in body mass index distribution The shape of the body mass index (BMI) distribution shifted to the right and the peak value decreased (Fig. ). The mean BMI increased from. kg m kg m -. At the same time, the BMI distribution increased its spread and flattened. The prevalence of overweight, based on Wld Health Organization (WHO) criteria (BMI = kg m - ), increased from.0% to.%. The rate of the weight gain and energy accumulation Coht body weight significantly increased in this -year period (P < 0.000). Average body weight increased from. to. kg, so the average weight gain was. kg. Assuming a linear rate of weight gain during this period, we estimated the median weight gain of the coht (Fig. ) to be 0. kg year - and. kg year - f the 0th percentile of weight increases. Using the assumptions described above about the efficiency of stage of excess energy, we calculated the rate of energy accumulation (this is the net total added energy over this -year period because of overweight) in the population. Figure shows the distribution of the daily energy accumulation in this coht over years a median daily energy accumulation of.0 kcal d - was estimated with a value of. kcal d - f the 0th percentile. Estimating the energy gap Energy derived from mixed composition diets is sted with an efficiency of at least 0% (,). Therefe, we calculated the energy gap f weight gain in China as kcal d -. This is the maximum degree of positive energy balance that is producing weight gain in 0% of the population. Estimation of the energy gap among different body mass index groups The rate of weight gain differed among different BMI groups. Thus, we classified the participants into underweight (BMI <. kg m - ), nmal (BMI. kg m - -. kg m - ), and overweight and obese (BMI kg m - and kg m - respectively), accding to the cut-off points defined by the WHO. Figures and show BMI distributions f weight gain and energy accumulation in the group that remained in the healthy range and the group that changed from nmal weight to Proption Figure Body mass index (BMI) distributions in and 00 f a coht of Chinese adults aged years in (N = ). BMI (kg m ) 00 0 The Auths Journal compilation 0 The International Association f the Study of Obesity. obesity reviews (Suppl. ), 0

3 obr_0 0 The energy gap in China F. Zhai et al. obesity reviews Proption Weight gain (kg year ) Figure The distribution f Chinese weight gain per year between and 00. The vertical lines crespond to the median weight gain and the 0th percentile gain. Proption Median.0 kcal d 0 th percentile. kcal d Energy stage (kcal d ) Figure The distribution of daily energy accumulation. 0 Proption Median (0. kg year ) Median (.0 kg year ) 0 th percentile (0. kg year ) Weight gain (kg year ) nmal to nmal nmal to overweight 0 th percentile (. kg year ) Figure The distribution of Chinese adult weight gain per year in the group remaining within the nmal body mass index (BMI) range and in the group transferring from the nmal BMI group to the overweight group ( 00). overweight. Table shows the estimate of the energy gap f each of the three BMI groups. The rate of weight gain and energy accumulation was lowest in the group remaining in the healthy weight range. The median weight gain was 0. kg year - and the 0th percentile was 0. kg year - ; the 0th percentile of the daily energy accumulation was. kcal d - ; and the cresponding energy gap was. kcal d -. 0 The Auths Journal compilation 0 The International Association f the Study of Obesity. obesity reviews (Suppl. ), 0

4 obr_0 obesity reviews The energy gap in China F. Zhai et al. 0 0 Figure The distribution of Chinese adult daily energy accumulation in the group (n = 0) remaining within the nmal body mass index range and the group transferring from nmal to overweight ( 00). Proption Median (. kcal d ) 0 th percentile (. kcal d ) Energy stage (kcal d ) nmal to nmal Table Estimates of the energy gap of different body mass index changes (accding to WHO cut-offs) Group Number Median weight gain (kg year - ) Remained within nmal range Nmal to overweight range change Remained within overweight range Median energy stage (kcal d - ) Median (. kcal d ) nmal to overweight 0 th percentile (. kcal d ) 0th percentile energy stage (kcal d - ) Males Females Urban Rural Males Females Urban Rural Males Females Urban Rural *Weight gain was significant over time in every group at P < Weight gain was not significantly different f men and women. Energy gap* (kcal d - ) 0 The fastest rate of weight gain and the highest daily energy accumulation were seen in the group who went from healthy weight to overweight during the -year period. The median rate of weight gain in this group was.0 kg year - and the 0th percentile was. kg year -. The 0th percentile f daily energy accumulation was. kcal d -, and the energy gap was. kcal d -. In the group that remained overweight, the median rate of weight gain was 0. kg year - and the 0th percentile was. kg year -. The 0th percentile f daily energy accumulation was. kcal d - and the energy gap was. kcal d -. When the BMI classification f Chinese adults () is applied to the analysis, using kg m - as the cut-off f overweight and kg m - f obesity (Table ), the average weight gain per year of all the three groups was then similar, but the median of energy stage was all lower than the figures in Table, using WHO cut-off 0 0 The Auths Journal compilation 0 The International Association f the Study of Obesity. obesity reviews (Suppl. ), 0

5 obr_0 0 The energy gap in China F. Zhai et al. obesity reviews Table Estimates of the energy gap f different body mass index range changes (accding to the cut-offs f Chinese adults) Group Number Median of weight gain (kg year - ) criteria. The energy gap f those remaining within the nmal weight range was. kcal day - ; f people increasing from nmal weight into the overweight range, the energy gap was kcal day - and, perhaps surprisingly, f people who remained overweight, their median energy stage was much lower than the comparable figures in Table. Discussion Obesity, once present, is difficult to reverse (,), and a population strategy based only on treating obesity is not likely to be effective. Preventing the gradual weight gain of the population that is leading to obesity is a me feasible strategy f a population especially a population such as China where obesity rates are not yet as high as those in most western countries. This paper provides a theetical basis f a population strategy of promoting behavioural changes focused on small reductions in energy intake and small increases in physical activity to minimize positive energy balance and prevent weight gain. Effts to promote decreased energy intake and increased physical activity may be me effective if there is a quantitative goal f the degree of change required. Many people attempt dramatic changes in dietary and physical activity patterns; however, such dramatic changes are rarely sustained over the long term. It may be me effective to promote smaller behavioural changes, if such changes are sufficient to prevent weight gain. Our data suggest that weight gain in China is less than that seen in the United States and in other western countries (,). Overall, we estimate that the energy gap f Chinese adults is only kcal d - as compared with an estimated energy gap in US adults of 00 kcal d - (). This means that even smaller degrees of behaviour changes are required to stop the obesity epidemic in China than in other countries. It may be particularly imptant to begin prevention effts in China quickly, as the energy gap may increase as the environment further moves towards one that facilitates obesity. The comparison of the results on the energy gap and energy stage/day between the analyses using WHO and Chinese BMI cut-offs also showed that given the higher disease risk at the same BMI of the Chinese, it is much Median energy stage (kcal d - ) 0th percentile energy stage (kcal d - ) Remained within nmal range Nmal to overweight ranges Remained within overweight range *Weight gain was significant over time in every group at P < Energy gap* (kcal d - ) easier f Chinese adults to move in terms of energy stage from the overweight categy into the obesity range. Thus, to keep BMI within the overweight range of. kg m -, the 0th percentile energy stage f this group of adults was only. kcal day - compared with kcal day -, if the WHO cut-off of BMI is applied. This also means that the energy gap required to trigger obesity and its hazards in China was only kcal/ day, i.e. about 0% lower than that required to reach the BMI level of Western obesity criteria. We estimate that modifying diet and/ physical activity to affect energy balance by only kcal d - would prevent excess weight gain in the population. This can be accomplished with very small changes in diet, in physical activity, the two in combination. Thus, it should be possible f most people to eat kcal d - less without changing the types of food they eat their typical meal patterns. F a typical adult with an energy intake of kcal d -, this would mean a reduction of only % in total daily energy intake. F example, this could be done by eating 0 g less of cooked rice, g less of steamed bread, pieces less of Jiaozi (dumplings), g less of oil each day. Even in those gaining weight at a higher rate and moving from a healthy weight to overweight, the energy gap can be closed with a reduction of only % in total daily energy intake. This could be accomplished with 0 g less of cooked rice, 0 g less of steamed bread 0 g less of oil. Alternatively, the energy gap could be closed entirely with small increases in physical activity and no changes in dietary intake. Most people could close the energy gap with only an additional 0 min of brisk walking each day. This would be an additional 000 m of walking each day an extra 0 00 step. Meover, this additional walking could be accumulated throughout the day. F those gaining the most weight, closing the energy gap would only require an extra min of walking each day an additional 00 m me each day 0 00 further steps. It is also possible to combine changes in diet and physical activity that would require even smaller changes in each behaviour. It is imptant to point out that our estimate is theetical and involves several assumptions. While the specific values f the energy gap would change slightly, based on different assumptions, the conclusion would remain that The Auths Journal compilation 0 The International Association f the Study of Obesity. obesity reviews (Suppl. ), 0

6 obr_0 obesity reviews The energy gap in China F. Zhai et al. 0 the weight gain that threatens to create an obesity epidemic in China could be prevented with very small lifestyle changes. If lifestyle changes do not occur and the weight gain of the population continues, it may require much larger changes in the future to achieve healthy body weights. Conflict of Interest Statement No conflict of interest was declared. Acknowledgements We wish to thank the Wking Group on Physical Activity in China of International Life Science Institute Focal Point in China f their suppt and thank all field interviewers f their data collection wk from nine co-dinative provinces of the CHNS wk team. We also wish to thank Dr James Hill who provided us the method to estimate a quantitative behaviour change goal required preventing the excess weight gain and gave us a lot of help. References. Wld Bank. Wld Development Indicats 0. In: Bank, W, (ed.). : Washington, DC, 0,.. Du S, Lu B, Zhai F, Popkin BM. A new stage of the nutrition transition in China. Public Health Nutr 0; :.. Du S, Mroz TA, Zhai F, Popkin BM. Rapid income growth adversely affects diet quality in China particularly f the po! Soc Sci Med 0; : 0.. Zhai F, Wang H, Du S,Ge K, Popkin BM. The changing trend of dietary pattern of Chinese population: an eight province case study in China. Acta Nutrimenta Sinica 0; :.. Wang H, Zhai F, Du S, Ge K, Popkin BM. The changing trend of dietary fat intake of Chinese population an eight provinces case study in China. Acta Nutrimenta Sinica 0; :.. Popkin BM, Du S. Dynamics of the nutrition transition toward the animal foods sect in China and its implications: a wried perspective. J Nutr 0; : S 0S.. Bell AC, Ge K, Popkin BM. Weight gain and its predicts in Chinese adults. Int J Obes Relat Metab Disd 0; : Bell AC, Ge K, Popkin BM. The road to obesity the path to prevention: motized transptation and obesity in China. Obes Res 0; 0:.. Wang L. The Synthetical Rept of the National Nutrition Survey of China 0. Public Health Press: Beijing, Zhai F, Wang H, Chang S, Fu D, Ge K, Popkin BM. The current status, trend, and influencing fact to malnutrition of infants and children in China. J Community Nutrition 0; :.. Wang H, Du S, Zhai F, Popkin BM. Trends in the distribution of body mass index among Chinese adults, aged years ( 00). Int J Obes (Lond) 0; :.. Hill JO, Wyatt HR, Reed GW, Peters JC. Obesity and the environment: where do we go from here? Science 0; :.. Brown WJ, Williams L, Fd JH, Ball K, Dobson AJ. Identifying the energy gap: magnitude and determinants of -year weight gain in midage women. Obes Res 0; :.. Bureau of Disease Control MOH. Guideline f Overweight and Obesity Control of Chinese Adults. People s Health Publishing House: Beijing, 0.. Haslam DW, James WP. Obesity. Lancet 0; :.. Maryon-Davis A. Weight management in primary care: how can it be made me effective? Proc Nutr Soc 0; : 0.. Wang H, He Y, Du S, Hao H. Trends in overweight among Chinese adults in some provinces from to 00. Acta Nutrimenta Sinica ; :.. Bray GA, Popkin BM. Dietary fat intake does affect obesity! Am J Clin Nutr ; :.. Giovannucci E, Colditz GA, Stampfer MJ, Willett WC. Physical activity, obesity, and risk of colectal adenoma in women (United States). Cancer Causes Control ; :.. Hill JO, Peters JC. Environmental contributions to the obesity epidemic. Science ; 0:.. Minehira K, Vega N, Vidal H, Acheson K, Tappy L. Effect of carbohydrate overfeeding on whole body macronutrient metabolism and expression of lipogenic enzymes in adipose tissue of lean and overweight humans. Int J Obes Relat Metab Disd 0; :.. Joosen AM, Bakker AH, Westerterp KR. Metabolic efficiency and energy expenditure during sht-term overfeeding. Physiol Behav 0; : The Auths Journal compilation 0 The International Association f the Study of Obesity. obesity reviews (Suppl. ), 0

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