Wang YC, Gortmaker SL, Sobol AM, Kuntz KM. Estimating the energy gap among U.S. children: A counterfactual approach. Pediatrics. 2006 Dec;118(6):e1721-33.
Our goal was to quantify the magnitude of energy imbalance responsible for the increase in body weight among US children during the periods 1988-1994 and 1999-2002.
We adopted a counterfactual approach to estimate weight gains in excess of normal growth and the implicit “energy gap”–the daily imbalance between energy intake and expenditure. On the basis of Centers for Disease Control and Prevention growth charts, we constructed weight, height, and BMI percentile distributions for cohorts 2 to 4 and 5 to 7 years of age in the 1988-1994 National Health and Nutrition Examination Survey (N = 5000). Under the counterfactual “normal-growth-only” scenario, we assumed that these percentile distributions remained the same as the cohort aged 10 years. Under this assumption, we projected the weight and height distributions for this cohort at 12 to 14 and 15 to 17 years of age on the basis of their baseline weight-for-age and stature-for-age percentiles. We compared these distributions with those for corresponding age groups in the 1999-2002 National Health and Nutrition Examination Survey (N = 3091) approximately 10 years after the 1988-1994 National Health and Nutrition Examination Survey. We calculated differences between the counterfactual and observed weight distributions and translated this difference into the estimated average energy gap, adjusting for increased total energy expenditure attributable to weight gain. In addition, we estimated the average excess weight accumulated among overweight adolescents in the 1999-2002 National Health and Nutrition Examination Survey, validating our counterfactual assumptions by analyzing longitudinal data from the National Longitudinal Survey of Youth and Bogalusa Heart Study.
Compared with the counterfactual scenario, boys and girls who were aged 2 to 7 in the 1988-1994 National Health and Nutrition Examination Survey gained, on average, an excess of 0.43 kg/year over the 10-year period. Assuming that 3500 kcal leads to an average of 1-lb weight gain as fat, our results suggest that a reduction in the energy gap of 110-165 kcal/day could have prevented this increase. Among overweight adolescents aged 12 to 17 in 1999-2002, results indicate an average energy imbalance ranging from 678 to 1017 kcal/day because of an excess of 26.5 kg accumulated over 10 years.
Quantifying the energy imbalance responsible for recent changes in weight distribution among children can provide salient targets for population intervention. Consistent behavioral changes averaging 110 to 165 kcal/day may be sufficient to counterbalance the energy gap. Changes in excess dietary intake (eg, eliminating one sugar-sweetened beverage at 150 kcal per can) may be easier to attain than increases in physical activity levels (eg, a 30-kg boy replacing sitting for 1.9 hours with 1.9 hours walking for an extra 150 kcal). Youth at higher levels of weight gain will likely need changes in multiple behaviors and environments to close the energy gap.
Wang YC, Gortmaker SL, Sobol AM, Kuntz KM. Uhakiki wa pengo la nishati kati ya watoto wa Marekani: mbinu ya kinyume. Matibabu ya watoto. Dec. 1, 2006 (S. 118) na Dec. 1, 2006 (S. 118) Utafiti huo ulilenga kuamua kiasi cha nishati iliyokuwa ikisababisha kuongezeka kwa uzito wa watoto wa Marekani katika kipindi cha mwaka 1998-1994. Sisi kupitishwa counterfactual mbinu ya kukadiria uzito gains zaidi ya ukuaji wa kawaida na implicit <unk> nishati pengo <unk> usahihi wa kila siku kati ya nishati ya ulaji na matumizi. Kwa kuzingatia chati za ukuaji wa Vituo vya Udhibiti na Kuzuia Magonjwa, tulijenga usambazaji wa asilimia ya uzito, urefu, na BMI kwa makundi ya watoto wa miaka 2 hadi 4 na 5 hadi 7 katika Uchunguzi wa Kitaifa wa Afya na Lishe wa 1988-1994. Katika hali ya kawaida ya ukuaji wa kawaida, tulidhani kwamba usambazaji huu wa asilimia ulibaki sawa na kundi la miaka 10. Kwa kuzingatia hii, tulipendekeza usambazaji wa uzito na urefu kwa kundi hili la watu wa umri wa miaka 12 hadi 14 na 15 hadi 17 kwa msingi wa asilimia ya msingi ya uzito kwa umri na urefu kwa umri. Kwa mfano, idadi ya watu walioathirika na ugonjwa huo ililinganishwa na idadi ya watu walioathiriwa na ugonjwa huo katika uchunguzi wa kitaifa wa afya na lishe wa mwaka 1999-2002 (NHSEN) na idadi ya watu walioathiriwa na ugonjwa huo katika uchunguzi wa kitaifa wa afya na lishe ya mwaka 1998-1994. Tulihesabu tofauti kati ya usambazaji wa uzito wa kawaida na uliotambuliwa na kugeuza tofauti hii katika pengo la wastani la nishati, tukirekebisha kwa kuongezeka kwa jumla ya matumizi ya nishati inayotokana na kuongezeka kwa uzito. Kwa kuongezea, tulikadiria wastani wa uzito wa ziada uliokusanywa kati ya vijana wenye uzito wa ziada katika Uchunguzi wa Kitaifa wa Afya na Lishe wa 1999-2002, tukithibitisha dhana zetu za kinyume kwa kuchanganua data ya urefu kutoka kwa Uchunguzi wa Kitaifa wa Longitudinal wa Vijana na Utafiti wa Moyo wa Bogalusa. Kwa mfano, katika kipindi cha miaka 10 ya uchunguzi wa afya na lishe ya mwaka wa 1988, wavulana na wasichana wenye umri wa miaka miwili hadi saba walipata uzito wa wastani wa kilo 0.43 kwa mwaka. "Kulinganisha na ""kcal 3500"" inamaanisha kwamba uzito wa kilo moja unazidi kuwa mafuta, matokeo yetu yanaonyesha kwamba kupunguza pengo la nishati la 110-165 kcal kwa siku inaweza kuzuia ongezeko hili." Katika vijana wenye uzito wa kupita kiasi wenye umri wa miaka 12 hadi 17, matokeo ya uchunguzi wa mwaka wa 2002 yanaonyesha kuwa wastani wa nishati ya wastani ya wastani ya wastani wa wastani wa wastani wa wastani wa wastani wa wastani wa wastani wa wastani wa wastani wa wastani wa wastani wa wastani wa wastani wa wastani wa wastani wa wastani wa wastani wa wastani wa wastani wa wastani wa wastani. Kupima usawa wa nishati unaohusika na mabadiliko ya hivi karibuni katika usambazaji wa uzito kati ya watoto inaweza kutoa malengo muhimu kwa uingiliaji wa idadi ya watu. Mabadiliko ya tabia ya kawaida ya kati ya 110-165 kcal kwa siku yanaweza kuwa ya kutosha kusawazisha pengo la nishati. Mabadiliko katika ulaji wa ziada (kwa mfano, kuondoa kinywaji kimoja chenye sukari ya 150 kcal kwa chupa) inaweza kuwa rahisi kufikia kuliko ongezeko la viwango vya shughuli za mwili (kwa mfano, mvulana wa kilo 30 akibadilisha kukaa kwa masaa 1.9 na kutembea kwa masaa 1.9 kwa kalori 150 za ziada). Vijana wenye viwango vya juu vya kuongezeka kwa uzito watahitaji mabadiliko katika tabia nyingi na mazingira ili kufunga pengo la nishati.