Increased food energy supply as a major driver of the obesity epidemic: a global analysis

Bull World Health Organ 2015;93:446–456 | doi: http://dx.doi.org/10.2471/BLT.14.150565 Research 446 Increased food energy supply as a major driver of the obesity epidemic: a global analysis Stefanie Vandevijvere,a Carson C Chow,b Kevin D Hall,b Elaine Umalia & Boyd A Swinburna Introduction Overweight and obesity have become major global public health problems. Worldwide, the proportion of adults with a body mass index (BMI) of 25 kg/m2 or greater increased from 28.8% to 36.9% in men, and from 29.8% to 38.0% in women between 1980 and 2013.1 Urgent action from governments and the food industry is needed to curb the epidemic.2 Action needs to be directed at the main drivers of the epidemic to meet the global target of halting the rise in obesity by 2025.3 The drivers of the obesity epidemic have been much de- bated.4–7 An increased food energy supply and the globalization of the food supply, increasing the availability of obesogenic ultra-processed foods, are arguments for a predominant food system driver5 of population weight gain. Increasing motoriza- tion and mechanization, time spent in front of small screens and a decrease in transport and occupational physical activity, point to reducing physical activity as a predominant driver6,8 of the obesity epidemic. A model used to predict body-weight gain, assuming no change in physical activity, follows the simple rule that a sustained increase in energy intake of 100 kJ per day leads to a predicted increase of 1 kg body weight on average, with half of the weight gain being achieved in about one year and 95% in about three years.9 According to this model, the oversupply of food energy is sufficient to drive the increase in energy intake and increases in body weight observed in the United Kingdom of Great Britain and Northern Ireland and the United States of America.9–11 This is despite the fact that, in the United States, food waste has increased by approximately 50% since 1974, reaching about 5800 kJ per person per day in 2003.12 Here we test the hypothesis that an increase in food energy supply is sufficient to explain increasing population body weight, using data from 24 high-income, 27 middle-income and 18 low-income countries. Methods Food energy supply Food balance sheets of the Food and Agriculture Organiza- tion of the United Nations (FAO) estimate the food supply of countries, by balancing local production, country-wide stocks and imports with exports, agricultural use for livestock, seed and some components of waste. Waste on the farm, during distribution and processing, as well as technical losses due to transformation of primary commodities into processed products are usually taken into account. However, losses of edible food, e.g. during storage, preparation and cooking, as plate-waste or domestic animal feed, or thrown away, are not considered. The data are expressed as the annual per capita supply of each food item available for human consumption.13 The FAO’s database contains national level data from 1961 to 2010 for 183 countries. For each country, data on food energy supply were extracted to match the time periods of data on adult body weight. Measured body weight Three major strategies were used to collect data on measured average adult body weight. First, an electronic search of major databases on obesity prevalence and BMI was performed, including the World Health Organization’s (WHO) global infobase,14 WHO’s global database on BMI,15 the International Association for the Study of Obesity (now World Obesity Objective We investigated associations between changes in national food energy supply and in average population body weight. Methods We collected data from 24 high-, 27 middle- and 18 low-income countries on the average measured body weight from global databases, national health and nutrition survey reports and peer-reviewed papers. Changes in average body weight were derived from study pairs that were at least four years apart (various years, 1971–2010). Selected study pairs were considered to be representative of an adolescent or adult population, at national or subnational scale. Food energy supply data were retrieved from the Food and Agriculture Organization of the United Nations food balance sheets. We estimated the population energy requirements at survey time points using Institute of Medicine equations. Finally, we estimated the change in energy intake that could theoretically account for the observed change in average body weight using an experimentally-validated model. Findings In 56 countries, an increase in food energy supply was associated with an increase in average body weight. In 45 countries, the increase in food energy supply was higher than the model-predicted increase in energy intake. The association between change in food energy supply and change in body weight was statistically significant overall and for high-income countries (P < 0.001). Conclusion The findings suggest that increases in food energy supply are sufficient to explain increases in average population body weight, especially in high-income countries. Policy efforts are needed to improve the healthiness of food systems and environments to reduce global obesity. a School of Population Health, University of Auckland, 261 Morrin Road, Auckland, New Zealand. b Laboratory of Biological Modeling, National Institutes of Health, Bethesda, United States of America. Correspondence to Stefanie Vandevijvere (email: s.vandevijvere@auckland.ac.nz). (Submitted: 17 November 2014 – Revised version received: 12 February 2015 – Accepted: 16 February 2015 ) R search Bull World Health Organ 2015;93:446–456| doi: http://dx.doi.org/10.2471/BLT.14.150565 447 Research Food energy supply and global obesityStefanie Vandevijvere et al. Ta bl e 1. Co un tr ie s a nd su rv ey s i nc lu de d in a g lo ba l a na ly sis o f f oo d en er gy su pp ly a nd b od y w ei gh t, 19 71 –2 01 0 Co un tr y In co m e le ve l o f co un tr y Ye ar Ag e ra ng e, ye ar s Fo od e ne rg y s up pl y, k J/ da y Fi rs t su rv ey Se co nd su rv ey Su rv ey 1 Su rv ey 2 Fi rs t su rv ey Se co nd su rv ey Fi rs t su rv ey Ch an ge Ex ce ss a t th e fir st su rv ey Al ge ria U pp er -M IC 19 86 20 03 Cr os s- se ct io na l s ur ve y ST EP S Su rv ey 16 –6 5 25 –6 4 11 3 85 1 46 4 2 95 8 Au st ra lia H IC 19 95 20 07 N at io na l N ut rit io n Su rv ey N at io na l H ea lth S ur ve y ≥ 1 8 ≥ 1 8 12 9 29 59 4 2 98 7 Ba ng la de sh LI C 19 96 20 07 N at io na l D em og ra ph ic H ea lth S ur ve y N at io na l D em og ra ph ic H ea lth S ur ve y 15 –4 9 15 –4 9 8 84 9 1 42 3 50 6 Ba rb ad os H IC 19 95 20 00 IC SH IB S tu dy Fo od C on su m pt io n an d An th ro po m et ric Su rv ey ≥ 2 5 18 –9 6 11 9 96 − 14 6 2 41 4 Be lg iu m H IC 19 86 19 91 W H O M O N IC A W H O M O N IC A 25 –3 4 25 –3 4 14 4 39 51 5 4 00 8 Be ni n LI C 19 96 20 01 N at io na l D em og ra ph ic H ea lth S ur ve y N at io na l D em og ra ph ic H ea lth S ur ve y 15 –4 9 15 –4 9 9 92 9 54 71 5 Bo liv ia (P lu rin at io na l St at e of ) Lo w er -M IC 19 94 20 08 N at io na l D em og ra ph ic H ea lth S ur ve y N at io na l D em og ra ph ic H ea lth S ur ve y 15 –4 9 15 –4 9 8 37 6 54 4 − 28 5 Bu rk in a Fa so LI C 19 93 19 98 N at io na l D em og ra ph ic H ea lth S ur ve y N at io na l D em og ra ph ic H ea lth S ur ve y 15 –4 9 15 –4 9 10 0 92 − 10 9 72 8 Ca m bo di a LI C 20 00 20 10 N at io na l D em og ra ph ic H ea lth S ur ve y ST EP S Su rv ey 15 –4 9 25 –6 4 8 90 8 1 05 9 19 7 Ca m er oo n Lo w er -M IC 19 98 20 04 N at io na l D em og ra ph ic H ea lth S ur ve y N at io na l D em og ra ph ic H ea lth S ur ve y 15 –4 9 15 –4 9 8 87 0 77 4 − 64 9 Ca na da H IC 19 71 20 08 N ut rit io n Ca na da S ur ve y Ca na di an C om m un ity H ea lth S ur ve y 20 –6 9 ≥ 1 8 12 1 59 2 33 9 2 63 6 Ch ad LI C 19 96 20 04 N at io na l D em og ra ph ic H ea lth S ur ve y N at io na l D em og ra ph ic H ea lth S ur ve y 15 –4 9 15 –4 9 7 74 0 89 5 − 1 66 5 Ch ile H IC 20 03 20 09 N at io na l H ea lth S ur ve y N at io na l H ea lth S ur ve y ≥ 1 7 ≥ 1 5 12 0 67 10 0 2 66 5 Ch in a U pp er -M IC 19 91 20 00 Ch in a H ea lth a nd N ut rit io n Su rv ey Cr os s- se ct io na l s ur ve y 20 –4 5 35 –7 4 10 4 47 1 54 8 1 99 6 Co lo m bi a U pp er -M IC 19 95 20 05 N at io na l D em og ra ph ic H ea lth S ur ve y N at io na l D em og ra ph ic H ea lth S ur ve y 15 –4 9 15 –4 9 10 8 37 18 8 2 51 0 Cz ec h Re pu bl ic H IC 19 93 20 02 H ea lth S ta tu s o f t he C ze ch P op ul at io n Su rv ey H ea lth S ta tu s o f t he C ze ch P op ul at io n Su rv ey 15 –7 5 15 –7 5 12 7 19 83 3 2 65 3 D en m ar k H IC 19 83 19 91 W H O M O N IC A W H O M O N IC A 25 –6 4 25 –6 4 12 7 40 86 2 2 79 5 D om in ic an Re pu bl ic U pp er -M IC 19 91 19 96 N at io na l D em og ra ph ic H ea lth S ur ve y N at io na l D em og ra ph ic H ea lth S ur ve y 15 –4 9 15 –4 9 9 02 5 30 1 74 9 Eg yp t Lo w er -M IC 19 92 20 05 N at io na l D em og ra ph ic H ea lth S ur ve y N at io na l D em og ra ph ic H ea lth S ur ve y 15 –4 9 15 –4 9 13 1 42 74 1 3 28 4 Er itr ea LI C 19 95 20 03 N at io na l D em og ra ph ic H ea lth S ur ve y N at io na l D em og ra ph ic H ea lth S ur ve y 15 –4 9 15 –4 9 6 56 9 − 63 − 2 27 2 Et hi op ia LI C 20 00 20 05 N at io na l D em og ra ph ic H ea lth S ur ve y N at io na l D em og ra ph ic H ea lth S ur ve y 15 –4 9 15 –4 9 7 56 5 76 1 − 1 34 3 Fi ji U pp er -M IC 19 80 20 04 N at io na l F oo d an d N ut rit io n Su rv ey ST EP S Su rv ey (N at io na l N ut rit io n Su rv ey ) 18 –5 5 18 –5 5 10 3 72 2 30 1 88 Fi nl an d H IC 19 87 19 97 Cr os s- se ct io na l p op ul at io n su rv ey Cr os s- se ct io na l p op ul at io n su rv ey 25 –6 4 25 –6 4 12 3 18 84 9 2 28 9 Fr an ce H IC 19 86 20 09 W H O M O N IC A N at io na l E pi de m io lo gi ca l S ur ve y 35 –6 4 ≥ 1 8 14 7 07 67 5 06 7 G ab on U pp er -M IC 20 00 20 09 N at io na l D em og ra ph ic H ea lth S ur ve y ST EP S Su rv ey 15 –4 9 15 –6 4 11 2 34 25 1 2 65 3 G er m an y H IC 19 83 20 09 W H O M O N IC A M ic ro ce ns us – H ea lth Q ue st io ns 25 –6 4 ≥ 1 8 14 2 67 58 2 4 30 5 (c on tin ue s. . . ) Bull World Health Organ 2015;93:446–456| doi: http://dx.doi.org/10.2471/BLT.14.150565448 Research Food energy supply and global obesity Stefanie Vandevijvere et al. Co un tr y In co m e le ve l o f co un tr y Ye ar Ag e ra ng e, ye ar s Fo od e ne rg y s up pl y, k J/ da y Fi rs t su rv ey Se co nd su rv ey Su rv ey 1 Su rv ey 2 Fi rs t su rv ey Se co nd su rv ey Fi rs t su rv ey Ch an ge Ex ce ss a t th e fir st su rv ey Gh an a Lo w er -M IC 19 93 20 03 N at io na l D em og ra ph ic H ea lth S ur ve y N at io na l D em og ra ph ic H ea lth S ur ve y 15 –4 9 15 –4 9 9 46 8 1 28 9 21 3 H ai ti LI C 19 94 20 05 N at io na l D em og ra ph ic H ea lth S ur ve y N at io na l D em og ra ph ic H ea lth S ur ve y 15 –4 9 15 –4 9 7 16 3 70 3 − 1 92 9 H un ga ry U pp er -M IC 19 82 19 87 W H O M O N IC A W H O M O N IC A 25 –6 4 25 –6 4 14 8 36 75 3 4 64 0 Ic el an d H IC 19 83 19 93 W H O M O N IC A W H O M O N IC A 25 –6 4 25 –6 4 13 3 34 − 34 3 2 75 7 In di a Lo w er -M IC 19 98 20 07 N at io na l D em og ra ph ic H ea lth S ur ve y ST EP S Su rv ey 15 –4 9 15 –6 4 9 65 7 11 3 71 5 In do ne sia Lo w er -M IC 19 83 20 01 Cr os s- se ct io na l s ur ve y ST EP S Su rv ey 15 –4 9 15 –6 5 9 61 5 27 6 1 42 3 Ira n (Is la m ic Re pu bl ic o f) U pp er -M IC 20 04 20 09 ST EP S Su rv ey ST EP S Su rv ey 15 –6 5 15 –6 4 13 1 29 25 3 54 0 Ire la nd H IC 19 85 20 09 Cr os s- se ct io na l s ur ve y N at io na l A du lt N ut rit io n Su rv ey 35 –6 4 18 –6 4 14 9 66 10 9 5 20 9 Isr ae l H IC 19 85 20 00 W H O M O N IC A N at io na l H ea lth a nd N ut rit io n Su rv ey 25 –6 4 25 –6 4 13 9 79 72 8 4 28 4 Ita ly H IC 19 83 19 93 W H O M O N IC A W H O M O N IC A 25 –6 4 25 –6 4 14 4 93 71 4 74 9 Jo rd an U pp er -M IC 19 97 20 02 Cr os s- se ct io na l s ur ve y N at io na l D em og ra ph ic H ea lth S ur ve y ≥ 2 5 15 –4 9 11 3 55 72 0 2 77 8 Ka za kh st an U pp er -M IC 19 95 19 99 N at io na l D em og ra ph ic H ea lth S ur ve y N at io na l D em og ra ph ic H ea lth S ur ve y 15 –4 9 15 –4 9 13 1 17 − 3 77 8 4 44 8 Ke ny a LI C 19 93 20 03 N at io na l D em og ra ph ic H ea lth S ur ve y N at io na l D em og ra ph ic H ea lth S ur ve y 15 –4 9 15 –4 9 7 95 4 44 4 − 1 31 8 Le ba no n U pp er -M IC 19 97 20 09 N at io na l c ro ss -s ec tio na l s ur ve y N at io na l c ro ss -s ec tio na l s ur ve y ≥ 2 0 ≥ 2 0 12 9 24 26 8 2 98 3 M ad ag as ca r LI C 19 97 20 05 N at io na l D em og ra ph ic H ea lth S ur ve y ST EP S Su rv ey 15 –4 9 25 –6 4 8 73 2 15 5 − 67 M al aw i LI C 19 83 20 09 Cr os s- se ct io na l s ur ve y ST EP S Su rv ey ≥ 1 5 25 –6 4 9 01 2 68 6 − 69 0 M al ay sia U pp er -M IC 19 96 20 05 N at io na l H ea lth & M or bi di ty S ur ve y ST EP S Su rv ey ≥ 2 0 25 –6 4 12 3 55 − 48 1 3 74 5 M al i LI C 19 95 20 06 N at io na l D em og ra ph ic H ea lth S ur ve y N at io na l D em og ra ph ic H ea lth S ur ve y 15 –4 9 15 –4 9 9 02 1 1 15 5 − 32 2 M al ta H IC 19 84 20 06 W H O M O N IC A Li fe st yl e Su rv ey 25 –6 4 18 –6 5 12 7 11 1 68 2 3 13 0 M au rit an ia Lo w er -M IC 20 00 20 06 N at io na l D em og ra ph ic H ea lth S ur ve y ST EP S Su rv ey 15 –4 9 15 –6 4 11 3 51 59 1 63 6 M on go lia Lo w er -M IC 20 05 20 09 ST EP S Su rv ey ST EP S Su rv ey 15 –6 4 15 –6 4 9 41 0 77 4 − 89 1 M or oc co Lo w er -M IC 19 92 20 03 N at io na l D em og ra ph ic H ea lth S ur ve y N at io na l D em og ra ph ic H ea lth S ur ve y 15 –4 9 15 –4 9 12 1 17 1 33 1 2 61 1 M oz am bi qu e LI C 19 97 20 03 N at io na l D em og ra ph ic H ea lth S ur ve y N at io na l D em og ra ph ic H ea lth S ur ve y 15 –4 9 15 –4 9 8 26 3 24 7 − 72 8 N ep al LI C 19 96 20 07 N at io na l D em og ra ph ic H ea lth S ur ve y ST EP S Su rv ey 15 –4 9 15 –6 4 9 23 4 67 4 76 6 N et he rla nd s H IC 20 00 20 09 H ea lth S ur ve y H ea lth S ur ve y 15 –6 5 15 –6 5 13 3 89 25 5 2 94 1 N ew Z ea la nd H IC 19 82 20 09 W H O M O N IC A N Z Ad ul t N ut rit io n Su rv ey 35 –6 4 15 –7 1 12 8 78 38 9 3 23 4 N ig er LI C 19 92 20 06 N at io na l D em og ra ph ic H ea lth S ur ve y N at io na l D em og ra ph ic H ea lth S ur ve y 15 –4 9 15 –4 9 8 14 2 1 59 8 − 1 02 5 N ig er ia Lo w er -M IC 19 99 20 03 N at io na l D em og ra ph ic H ea lth S ur ve y N at io na l D em og ra ph ic H ea lth S ur ve y 15 –4 9 15 –4 9 11 1 09 − 13 4 1 74 1 N or w ay H IC 19 90 20 01 Pr os pe ct iv e po pu la tio n- ba se d su rv ey Pr os pe ct iv e po pu la tio n- ba se d su rv ey ≥ 2 0 20 –7 9 13 1 96 99 2 3 28 0 Pe ru U pp er -M IC 19 91 20 09 N at io na l D em og ra ph ic H ea lth S ur ve y N at io na l D em og ra ph ic H ea lth S ur ve y 15 –4 9 15 –4 9 9 07 5 1 65 3 87 4 (. . . co nt in ue d) (c on tin ue s. . . ) Stefanie Vandevijvere et al. Food energy supply and global obesity Research 449Bull World Health Organ 2015;93:446–456| doi: http://dx.doi.org/10.2471/BLT.14.150565 Federation) database16 and the Organ- isation for Economic Co-operation and Development’s health data.17 As these databases only included data on obesity rates or mean BMI, the original sources of the data were searched. Second, data on average measured body weight were gathered from reports of national health and nutrition surveys in various countries. The WHO MONICA proj- ect18 and WHO STEPwise approach to surveillance (STEPS) country reports19 included anthropometric measures for male and female adult samples. We also calculated body weight for women of child-bearing age using mean BMI and height data from Demographic and Health Surveys.20 Third, an electronic search of Medline was conducted. For each country, a separate search was per- formed using the following keywords: “obesity”, “weight”, “anthropometric”, “BMI”, “health survey” and “national survey” (using the Boolean operator OR). Finally, specific national health and/or nutrition surveys identified by some of the above sources were elec- tronically searched. Studies fulfilling the following cri- teria were extracted: (i) weight was mea- sured after 1961 and again before 2010 (to match the FAO food balance sheet data); (ii) the study samples were representative of a national or subnational adolescent or adult population; (iii) the survey method was comparable with previous or future surveys conducted in the country; (iv) the year in which each survey was conducted could be identified; at least four years elapsed between the two sur- veys; and (v) FAO food supply data were available for the relevant period. If there were more than two eligible studies from a country, the surveys which we judged to be the best quality were included. Criteria for estimating study quality in- cluded national representativeness, sample size and length of time between surveys. Demographic data Demographic data (total population, by age and sex) were retrieved from the United Nations Department of Econom- ic and Social Affairs.21 Average female and male height at survey time points were derived from http://www.averageh- height.co/. For 13 countries, data were not available and average height data from a neighbouring country were used for calculating energy requirements. Co un tr y In co m e le ve l o f co un tr y Ye ar Ag e ra ng e, ye ar s Fo od e ne rg y s up pl y, k J/ da y Fi rs t su rv ey Se co nd su rv ey Su rv ey 1 Su rv ey 2 Fi rs t su rv ey Se co nd su rv ey Fi rs t su rv ey Ch an ge Ex ce ss a t th e fir st su rv ey Po la nd H IC 19 83 19 92 W H O M O N IC A W H O M O N IC A 35 –6 4 35 –6 4 14 0 46 24 3 4 33 9 Rw an da LI C 20 00 20 05 N at io na l D em og ra ph ic H ea lth S ur ve y N at io na l D em og ra ph ic H ea lth S ur ve y 15 –4 9 15 –4 9 7 81 2 67 4 − 1 38 5 Sa ud i A ra bi a H IC 19 96 20 04 Cr os s- se ct io na l s ur ve y ST EP S Su rv ey ≥ 1 9 25 –6 4 12 2 47 51 9 1 44 8 Se ne ga l Lo w er -M IC 19 92 20 05 N at io na l D em og ra ph ic H ea lth S ur ve y N at io na l D em og ra ph ic H ea lth S ur ve y 15 –4 9 15 –4 9 9 42 7 50 6 − 15 5 So ut h Af ric a U pp er -M IC 19 98 20 03 N at io na l D em og ra ph ic H ea lth S ur ve y N at io na l D em og ra ph ic H ea lth S ur ve y 15 –6 5 15 –6 5 11 9 29 39 7 2 24 3 Sw ed en H IC 19 85 20 01 W H O M O N IC A IN TE RG EN E Pr oj ec t 25 –6 4 25 –6 4 12 4 56 63 6 2 70 3 Sw itz er la nd H IC 19 85 19 94 W H O M O N IC A W H O M O N IC A 35 –6 4 25 –6 4 14 2 42 − 31 0 4 59 0 To go LI C 19 98 20 10 N at io na l D em og ra ph ic H ea lth S ur ve y ST EP S Su rv ey 15 –4 9 15 –6 4 9 15 0 73 6 − 46 9 Tu rk ey U pp er -M IC 19 93 20 03 N at io na l D em og ra ph ic H ea lth S ur ve y N at io na l D em og ra ph ic H ea lth S ur ve y 15 –4 9 15 –4 9 15 5 31 − 60 2 7 25 1 U ni te d Ki ng do m H IC 19 93 20 09 H ea lth S ur ve y fo r E ng la nd H ea lth S ur ve y fo r E ng la nd ≥ 1 6 ≥ 1 6 13 4 68 89 1 3 72 4 U ni te d St at es H IC 19 72 20 04 N at io na l H ea lth a nd N ut rit io n Ex am in at io n Su rv ey N at io na l H ea lth a nd N ut rit io n Ex am in at io n Su rv ey 20 –7 4 20 –7 4 12 7 70 3 21 3 2 97 9 Uz be ki st an Lo w er -M IC 19 96 20 02 N at io na l D em og ra ph ic H ea lth S ur ve y H ea lth E xa m in at io n Su rv ey 15 –4 9 15 –4 9 12 2 42 − 2 61 5 2 80 3 Zi m ba bw e LI C 19 94 19 99 N at io na l D em og ra ph ic H ea lth S ur ve y N at io na l D em og ra ph ic H ea lth S ur ve y 15 –4 9 15 –4 9 8 03 7 28 0 − 1 34 3 LI C: lo w -in co m e co un tr y; L ow er -M IC : lo w er -m id dl e- in co m e co un tr y; H IC : h ig h- in co m e co un tr y; IC SH IB : t he In te rn at io na l C om pa ra tiv e St ud y of H yp er te ns io n in B la ck s; Up pe r-M IC : u pp er -m id dl e- in co m e co un tr y; W HO : W or ld H ea lth O rg an iza tio n. N ot e: E st im at io ns o f p op ul at io n en er gy re qu ire m en ts w er e pe rfo rm ed fo r e ac h co un tr y us in g th e In st itu te o f M ed ic in e eq ua tio ns fo r m al es a nd fe m al es .22 E ne rg y ex ce ss w as c al cu la te d by su bt ra ct in g en er gy re qu ire m en ts a t t he fi rs t s ur ve y fro m th e en er gy su pp ly a t t he sa m e su rv ey . (. . . co nt in ue d) Stefanie Vandevijvere et al.Food energy supply and global obesity Research 450 Bull World Health Organ 2015;93:446–456| doi: http://dx.doi.org/10.2471/BLT.14.150565 Data analysis Three types of analysis were performed. First, we compared the changes in food energy supply with changes in average body weight over time for each coun- try. Second, estimates of population energy requirements at survey time points were performed for each country using Institute of Medicine equations.22 Low active physical activity levels (1.4 ≤ PAL <1.6) were assumed for high- and upper-middle-income countries. Ac- tive physical activity levels (1.6 ≤ PAL <1.9) were used for all other countries. Finally, we used a physiologically-based, experimentally-validated predictive energy intake body-weight model, to es- timate the change in average population energy intake that would be required to account for the observed change in average body weight.9 Results In total, 83 countries had at least two surveys with data on measured body weight; 24 countries had more than two surveys at different time points. We excluded countries where the period between surveys was less than four years (eight countries), survey populations were not comparable in terms of area representativeness (eight countries) or FAO food supply data for the country were not available (three countries). Survey pairs from 69 countries were included. Of those, 36 survey pairs in- cluded data for women of childbearing age only. One survey pair (Saudi Arabia) included data for men only. Data from 24 high-income, 27 middle-income and 18 low-income countries were included. The average period between the surveys was 12 years (range 4–37 years; Table 1). At the time of the initial survey, food en- ergy supply was greater than the average energy requirements in 52 countries. For 37 of these countries, this excess food energy supply was more than 2000 kJ/ day (Table 1). For 56 countries (81%) both food energy supply and body weight in- creased between the survey pairs. For 45 of these countries (80%) the increase in food energy supply was more than suf- ficient to explain the increase in average body weight. This is shown in Fig. 1 with 56/69 countries being in the top right quadrant and 45/56 being to the right of the model-predicted change in energy intake needed to produce the increase in mean body weight for that country. This same pattern was observed for countries of all income levels (Fig. 2, Fig. 3, Fig. 4 and Fig. 5). For 11 countries (Benin, Chile, the Dominican Republic, Gabon, India, Indonesia, Ireland, Italy, Leba- non, Mauritania and New Zealand) in the top right quadrant, the increase in food energy supply was insufficient to account for the observed increase in weight (Fig. 1). Five countries (Barbados, Burkina Faso, Kazakhstan, Nigeria and Switzer- land) experienced reductions in both food energy supply and average body weight. For Kazakhstan the food energy supply decreased by 3778 kJ/day, from 13 117 kJ/day to 9339 kJ/day over a four year period (Table 1), accompanied by a decrease in average body weight of 0.9 kg. For the four other countries, de- creases in food energy supply were much more modest (100–300 kJ/day; Table 1). Fig. 1. Change in food energy supply and change in average body weight for 69 countries, 1971–2010 Ch an ge s i n bo dy w ei gh t ( kg ) 12 10 8 6 4 2 –4000 –3500 –3000 –2500 –2000 –1500 –1000 –500 0 500 1000 1500 2000 2500 3000 3500 4000 –2 Changes in food energy (kJ/day) Modelled data HIC LIC Lower-MIC Upper-MIC LIC: low-income countries; Lower-MIC: lower-middle-income countries; HIC: high-income countris; Upper-MIC: upper-middle-income countries. Note: The dots representing the modelled data are the estimated change in energy intake required to account for the change in average body weight of the population.9 Bull World Health Organ 2015;93:446–456| doi: http://dx.doi.org/10.2471/BLT.14.150565 451 Research Food energy supply and global obesityStefanie Vandevijvere et al. For five other countries (Eritrea, Iceland, Malaysia, Turkey and Uzbeki- stan), discordant changes were observed with reductions in food energy supply over the same period as increases in av- erage body weight. The decrease in food energy supply was highest for Uzbeki- stan (2615 kJ/day) and lowest for Eritrea (63 kJ/day; Table 1). Apart from Eritrea, food energy supply at baseline for those five countries was relatively high (rang- ing from 12 242 to 15 531 kJ/day) and higher than the values of at least half of the other countries included in this study. In addition, excess food energy supply at baseline was high for those five countries (2757–7251 kJ/day; Table 1). For three countries (the Islamic Republic of Iran, Rwanda and South Africa) there were discordant changes in the other direction with increases in food energy supply over the same period as reductions in average body weight. However, for two of those countries, the change in average weight was small (a reduction of 5 g for the Islamic Republic of Iran and 100 g for South Africa). In Rwanda, the reduction in weight was 800 g while the food energy supply over the same time period increased by 674 kJ/day (Table 1). The correlation between the change in food energy supply and change in average body weight was significant (P = 0.011). When stratifying by type of country, associations were significant for high-income countries (P < 0.001), but not for other country groups. Discussion For most of the countries included in this study, the change in per capita food energy supply was greater than the change in food energy intake theoreti- cally required to explain the observed change in average body weight. The associations between changes in food energy supply and average population body weight were significant overall and for high-income countries. This suggests that, in high-income countries, a growing and excessive food supply is contributing to higher energy intake, as well as to increasing food waste.12 Other factors, such as a decrease in physical activity, may also lead to an increase in body weight and could oc- cur simultaneously with an increase in food energy supply. It has been shown that among 3.7 million participants in the United States at the county level, in- creased physical activity has only a very small impact on obesity prevalence.23 It is likely that in some countries, such as China, the impact of reduced physical activity on obesity is more important.24,25 A reduction in physical activity with no compensatory drop in energy intake will cause weight gain until sufficient weight is gained to create energy bal- ance (through both an increased resting metabolic rate and increased energy required to move the larger body). Researchers have suggested ad- ditional contributing factors for obe- sity, such as pollutants, infections and changes in the gut microbiota. These fac- tors have an effect on metabolism, body composition and/or energy balance efficiencies. However, more evidence is needed to understand the importance of these factors in weight gain.26 Ideally, the cause of obesity in humans would be assessed through randomized controlled trials, where food energy availability is increased randomly and average body Fig. 2. Change in food energy supply and change in average body weight for 24 high-income countries, 1971–2009 Ch an ge s i n bo dy w ei gh t ( kg ) 12 10 8 6 4 2 –2 Modelled data HIC –4000 –3500 –3000 –2500 –2000 –1500 –1000 –500 0 500 1000 1500 2000 2500 3000 3500 4000 Changes in food energy (kJ/day) HIC: high-income countries. Note: The dots representing the modelled data are the estimated change in energy intake required to account for the change in average body weight of the population.9 Bull World Health Organ 2015;93:446–456| doi: http://dx.doi.org/10.2471/BLT.14.150565452 Research Food energy supply and global obesity Stefanie Vandevijvere et al. weight is then measured. However, such an experiment is not practical, since it is difficult to measure food intake over long time periods and it would require that non-obese subjects be randomly assigned to environments with different food energy supplies. Our findings suggest that there is an excess of energy available from an increasing national average food en- ergy supply in countries of varying in- come levels.9 Therefore, policy efforts need to focus on reducing population energy intake through improving the healthiness of food systems and environments.5,11,27 Achieving WHO’s target to halt the rise in obesity by 2025 will require major action by governments and the food industry.3 A combination of several policy actions will be needed to significantly improve diets and reduce overconsumption.2 These policies include restriction of unhealthy food marketing to children, front-of-pack supplementary nutrition labelling,28 food pricing strategies,29 improving the quality of foods in schools30 and other public sector set- tings. The impact of trade and invest- ment agreements31 and agricultural policies32 on domestic food environ- ments should be assessed. The main strength of this study is the inclusion of nationally representa- tive body weight and food energy sup- ply data for a range of countries and over many years. Weaknesses include the limitations on the measurement of national per capita food energy sup- ply (e.g. losses of edible food during storage, preparation and cooking, as plate-waste or domestic animal feed, and subsistence farming are not taken into account) and the variable qual- ity of energy supply data. In addition, low- and middle-income countries, in different phases of the nutrition transi- tion,33,34 are likely to have poorer data and have higher levels of subsistence farming, which is not included in the FAO food supply data.13 The association between changes in food supply and changes in body weight may be confounded by changes in physical activity levels, changes in food waste or changes in the demo- graphic profile of countries. Demo- graphic changes, particularly size, ageing, and racial/ethnic diversifica- tion of populations, may contribute to increasing obesity levels.35 About half the data sets on weight status used in this study are for women only and thus only represent half of the population. A limitation of the energy-balance model is that it assumes that metabolic physi- ology and physical activity levels are similar globally. While this is likely to be true for industrialized countries for which accurate data on the relationship between energy expenditure and body weight are available and for which the model has been calibrated, it is not clear how well this assumption applies for developing countries. The model also assumes that population-wide changes in physical activity are negligible over the periods investigated. In conclusion, in high-income countries, observed increases in body weight over recent decades are as- sociated with increased food energy supply. In addition, increases in food energy supply are sufficient to explain increases in average population weight. Due to the nutrition transition and a potential decrease in physical activity, Fig. 3. Change in food energy supply and change in average body weight for 15 upper-middle-income countries, 1980–2009 Ch an ge s i n bo dy w ei gh t ( kg ) 12 10 8 6 4 2 –4000 –3500 –3000 –2500 –2000 –1500 –1000 –500 0 500 1000 1500 2000 2500 3000 3500 4000 Changes in food energy (kJ/day) –2 Modelled data Upper-MIC Upper-MIC: upper-middle-income countries. Note: The dots representing the modelled data are the estimated change in energy intake required to account for the change in average body weight of the population.9 Bull World Health Organ 2015;93:446–456| doi: http://dx.doi.org/10.2471/BLT.14.150565 453 Research Food energy supply and global obesityStefanie Vandevijvere et al. Fig. 4. Change in food energy supply and change in average body weight for 12 lower-middle-income countries, 1983–2009 Ch an ge s i n bo dy w ei gh t ( kg ) 12 10 8 6 4 2 –4000 –3500 –3000 –2500 –2000 –1500 –1000 –500 0 500 1000 1500 2000 2500 3000 3500 4000 Changes in food energy (kJ/day) –2 Modelled data Lower-MIC Lower-MIC: lower-middle-income countries. Note: The dots representing the modelled data are the estimated change in energy intake required to account for the change in average body weight of the population.9 Fig. 5. Change in food energy supply and change in average body weight for 18 low-income countries, 1983–2009 Ch an ge in b od y w ei gh t ( kg ) 12 10 8 6 4 2 –4000 –3500 –3000 –2500 –2000 –1500 –1000 –500 0 500 1000 1500 2000 2500 3000 3500 4000 Changes in food energy (kJ/day) Modelled data LIC –2 LIC: low-income countries. Note: The dots representing the modelled data are the estimated change in energy intake required to account for the change in average body weight of the population.9 Bull World Health Organ 2015;93:446–456| doi: http://dx.doi.org/10.2471/BLT.14.150565454 Research Food energy supply and global obesity Stefanie Vandevijvere et al. the same pattern is expected to occur in low- and middle-income countries in the future. Policy efforts should focus on reducing population energy intake through improving the healthiness of food systems and environments. ■ Funding: Stefanie Vandevijvere and Boyd Swin- burn are funded by the University of Auckland Vice Chancellor’s strategic fund. Carson Chow and Kevin Hall are funded by the intramural research pro- gramme of the NIH’s National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), USA. Competing interests: None declared. 摘要 食品能量供给增加是肥胖症流行的主要促成因素：一项全球性的分析 目的 我们调查了全国食品能量供给和人口平均体重之 间的变化联系。 方法 我们从 18 个低收入国家的平均体重数据。平均 体重的变化来源于最少相差 4 年的两组研究（不同年 份，1971–2010 年）。所选的两组研究被认为是代表了 国家或地方范围内青少年或成年人口的情况。食品能 量供给的数据是从联合国粮食和农业组织的食品平衡 表检索而得。我们采用医学研究所的方程式估计了在 调查时间点的人口能量需求。最后，我们通过模型估 计了能够在理论上对平均体重观察得到的变化产生影 响的能量摄入的变化情况。 结果 在 56 个国家中，食品能量供给的增加与平均体 重的增加相互联系。与通过模型预测的能量摄入相 比， 45 个国家中食品能量供给的增加更高。能量供给 变化与体重变化之间的联系在高收入国家中从整体上 存在统计学上的显著差异 (P < 0.001)。 结论 结果表明食品能量供给的增加足以构成平均人口 体重增加的原因，尤其是在高收入国家。我们还需要 加大政策力度，改善食品系统和环境的健康，从而降 低全球肥胖率。 Résumé L’accroissement de la disponibilité énergétique alimentaire comme facteur majeur de l’épidémie d’obésité : une analyse à l’échelle internationale Objectif Nous avons enquêté sur les associations entre l’évolution des disponibilités énergétiques alimentaires nationales et celle du poids moyen des populations. Méthodes Nous avons collecté les données de 24 pays à revenu élevé, 27 pays à revenu intermédiaire et 18 pays à faible revenu concernant le poids moyen de la population, tel que renseigné dans les bases de données mondiales, les rapports d’enquêtes nationales sur la santé et la nutrition et des articles examinés par comité de lecture. Les changements de poids ont été déterminés par des paires d’études espacées d’au moins quatre années d’intervalle (diverses années sur la période 1971 à 2010). Les paires d’études sélectionnées sont considérées comme représentatives d’une population adolescente ou adulte, à des échelles nationales ou sous-nationales. Les données relatives aux disponibilités énergétiques alimentaires ont été extraites des bilans des disponibilités alimentaires de l’Organisation des Nations Unies pour l’alimentation et l’agriculture (FAO). Nous avons estimé les besoins caloriques des populations aux moments de réalisation des enquêtes en utilisant les équations de l’Institute of Medicine (IOM). Enfin, à l’aide d’un modèle validé expérimentalement, nous avons estimé le changement صخلم يلماع ليلتح :ةنادبلا ءابول سييئرلا ببسلما اهرابتعاب ةيئاذغلا ةقاطلا تادادمإ ةدايز تادادمإ في تايرغتلا ينب ام تاطابترلاا صيقتب انمق ضرغلا .ناكسلل مسلجا نزو طسوتم فيو ةينطولا ةيئاذغلا ةقاطلا لخدلا ةيلاع نادلبلا نم اًدلب 24 نم تانايب انعجم دقل ةقيرطلا طسوتم لوح لخدلا ضفخنم اًدلب 18و لخدلا طسوتم اًدلب 27و ةينطولا حسلما ريراقتو ،ةيلماعلا تانايبلا دعاوق نم مسلجا نزو تاضارعتسلا تعضخ يتلا تاساردلاو ،ةيذغتلاو ةحصلل جاوزأ نم ةدمتسم مسلجا نزو طسوتم في تايرغتلا تناكو .ةّيدن ،ةديدع تاونس( لقلأا لىع تاونس عبرأ ةدلم تدعابت يتلا ةساردلا جاوزأ رابتعا متو .)2010 ماع لىإ 1971 ماع ينب ام ةترفلا في ةقهارلما نس في ةيناكسلا تاعاطقلل ةلثمم نوكتل ةراتخلما ةساردلا لىع لوصلحا مت .ينطولا نود وأ ينطولا ديعصلا لىع ينغلابلا وأ ةمظنلم ةينيومتلا تاينازيلما نم ةيئاذغلا ةقاطلا تادادمإ تانايب ةقاطلا تابلطتم انرّدق دقو .ةدحتلما مملأل ةعباتلا ةعارزلاو ةيذغلأا ةصالخا تلاداعلما مادختساب حسملل ةينمز تاترف في ناكسلل دق يذلا ةقاطلا لوخدم في يرغتلا انرّدق ،اًيرخأو .بطلا دهعمب في دصرلل عضالخا يرغتلا نع ةيرظنلا ةيحانلا نم ًلاوؤسم نوكي هتيقادصم نم ققحتلا مت جذومن مادختساب مسلجا نزو طسوتم .براجتلا عقاو نم ةيئاذغلا ةقاطلا تادادمإ في ةدايزلا تطبترا ،اًدلب 56 في جئاتنلا في ةدايزلا تناك ،اًدلب 45 في .مسلجا نزو طسوتم في ةدايزب ةيئاذغلا ةقاطلا لوخدم ةدايز نم لىعأ ةيئاذغلا ةقاطلا تادادمإ ةقاطلا تادادمإ في يرغتلا ينب طابترلاا ناكو .جذومنلا ابه أبنت يتلا ةيئاصحلإا ةيحانلا نم اًسوملم مسلجا نزو في يرغتلاو ةيئاذغلا .)0.001 < لماتحلاا( لخدلا ةيلاع نادلبلل ةبسنلابو لياجمإ لكشب ةيئاذغلا ةقاطلا تادادمإ في تادايزلا نأ لىإ جئاتنلا يرشت جاتنتسلاا مايس لاو ،ناكسلل مسلجا نزو طسوتم في تادايزلا حشرل ةيفاك للاخ نم دوهج لذب لىإ ةجاح كانهو .لخدلا ةيلاع نادلبلا في ضفلخ ةيئاذغلا تائيبلاو مظنلا ةملاس ينسحتل تاسايسلا .ةيلماعلا ةنمسلا تلادعم Bull World Health Organ 2015;93:446–456| doi: http://dx.doi.org/10.2471/BLT.14.150565 455 Research Food energy supply and global obesityStefanie Vandevijvere et al. de l’apport calorique qui pourrait correspondre théoriquement aux changements observés du poids moyen. Résultats Dans 56 pays, une augmentation de la disponibilité énergétique alimentaire a été associée à une augmentation du poids moyen. Dans 45 pays, l’augmentation de la disponibilité énergétique alimentaire a été plus importante que l’augmentation de l’apport calorique déduit du modèle. L’association entre l’évolution de la disponibilité énergétique alimentaire et le changement de poids a été statistiquement significative, de manière générale et dans les pays à revenu élevé (P < 0,001). Conclusion Ces résultats suggèrent que l’accroissement de la disponibilité énergétique alimentaire suffit à expliquer les augmentations du poids moyen de la population, notamment dans les pays à revenu élevé. Des efforts politiques sont nécessaires pour obtenir des environnements et systèmes alimentaires plus sains afin de réduire l’obésité à l’échelle mondiale. Резюме Повышение калорийности пищи как основной фактор, способствующий распространению эпидемии ожирения: глобальный анализ Цель Исследование взаимосвязи между изменениями в калорийности продуктов питания и средней массы тела у населения. Методы Были собраны данные о средней массе тела у населения на основании глобальных баз данных, рецензируемых документов и отчетов о национальном исследовании состояния здоровья и питания населения. Анализ проводился по данным из 24 стран с высоким уровнем дохода, 27 стран со средним уровнем дохода и 18 стран с низким уровнем дохода. Информация об изменении средней массы тела была получена в ходе исследования пар, возраст которых отличался как минимум на четыре года (различные года в период с 1971 по 2010 г.). Выбранные для исследования пары считались характерными для подросткового и взрослого населения на национальном или субнациональном уровне. Данные о калорийности пищи были получены из продовольственного баланса Продовольственной и сельскохозяйственной Организации Объединенных Наций. Энергетические потребности населения оценивались на момент исследования с использованием уравнений Института медицины. Изменения в калорийности потребляемой пищи, которые теоретически могли служить причиной для наблюдаемого изменения средней массы тела, оценивались с использованием экспериментально проверенной модели. Результаты В 56 странах повышение калорийности пищи было связано с увеличением средней массы тела. В 45 странах повышение калорийности пищи превышало значение, прогнозируемое моделью. Взаимосвязь между изменением калорийности пищи и изменением массы тела была статистически значима повсеместно, в том числе и для стран с высоким уровнем дохода (P < 0,001). Вывод Результаты исследований свидетельствуют о том, что повышение калорийности пищи с достаточной вероятностью объясняет увеличение средней массы тела у населения, особенно в странах с высоким уровнем дохода. Для снижения уровня ожирения в мировом масштабе нужно предпринимать стратегические меры, направленные на создание пищевого окружения и систем питания, в большей мере способствующих здоровому уровню жизни. Resumen El aumento del suministro de energía alimentaria como el principal impulsor de la epidemia de obesidad: un análisis internacional Objetivo Se investigó la relación entre los cambios en el suministro nacional de energía alimentaria y el peso corporal medio de la población. Métodos Se recopilaron datos de 24 países de ingresos altos, 27 de ingresos medios y 18 de ingresos bajos en relación con el peso corporal medio a partir de bases de datos internacionales, informes de estudios sobre salud y nutrición nacional y estudios revisados por homólogos. Los cambios en el peso corporal medio se obtuvieron a partir de estudios por pares realizados con una diferencia de al menos cuatro años (distintos años, 1971-2010). Los estudios seleccionados se consideraron representativos de una población adolescente o adulta, a nivel nacional o subnacional. Los datos de suministro de energía alimentaria se obtuvieron de los balances sobre alimentación de la Organización de las Naciones Unidas para la Agricultura y la Alimentación. Se calcularon los requisitos energéticos de la población en el momento de la realización de los estudios utilizando ecuaciones del Instituto de Medicina. Por último, se calculó el cambio en la ingesta de energía que, en teoría, podría explicar el cambio observado en el peso corporal medio mediante el uso de un modelo experimentalmente validado. Resultados En 56 países, se relacionó un aumento del suministro de energía alimentaria con un aumento del peso corporal medio. En 45 países, el aumento del suministro de energía alimentaria fue mayor que el aumento de ingesta energética previsto en el modelo. La relación entre el cambio en el suministro energético alimentario y el cambio en el peso corporal fue estadísticamente significativo en general y en países de ingresos altos (P < 0,001). Conclusión Los resultados sugieren que el incremento en el suministro de energía alimentaria basta para explicar el aumento del peso corporal medio de la población, en especial en países de ingresos altos. Es necesario que los políticos se esfuercen por mejorar la salubridad de los entornos y sistemas alimentarios para reducir la obesidad mundial References 1. Ng M, Fleming T, Robinson M, Thomson B, Graetz N, Margono C, et al. Global, regional, and national prevalence of overweight and obesity in children and adults during 1980–2013: a systematic analysis for the Global Burden of Disease Study 2013. 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