Energy balance explores the relationship between energy input (in the form of nutrient intake) and energy expenditure from metabolism, growth and physical activity. For most children and families, lifestyle patterns are established early, affecting children not only while they're young but throughout their lives. To avoid the harmful health consequences of less-than-optimal choices, it's imperative to help families with young children learn to match food intake with energy expenditure.
Breastfeeding Meets Early Caloric Requirements
While it is not desirable to teach families to count calories, it is important for them to understand that the basic caloric requirements in young children are in large part dictated by growth rate. For example, during the first year of life when a child triples his or her weight and gains 14-15 pounds, this rapid growth requires more energy, protein, and other essential nutrients per kilogram of body weight than at any other time. Excessive energy requirements continue so that from two-to-three years of age, children require 102 calories per kilogram of body weight; from four-to-six years, 90 calories; and from 7-10 years, 70 calories.2
Breastfeeding is the most effective way to meet these caloric and nutrient requirements and to mitigate overweight and obesity.3 Numerous studies and meta-analyses show a consistent beneficial effect of breastfeeding on childhood and adult obesity.4,5,6 At least in part, breastfeeding may reduce the risk of obesity because it allows the baby to naturally self-regulate. This may be mediated by leptin, which is present in human milk. Leptin is a hormone that regulates food intake and body fatness. Leptin deficiency has been described as a cause of obesity, and leptin replacement has led to its resolution in select cases. Unfortunately, most people who are obese are not leptin deficient, but rather resistant to its appetite-regulating effects.7
Breastfeeding also affects energy and protein intake, insulin secretion and fat deposition and adipocyte development.8 While researchers have had difficulty demonstrating a dose-response curve for the duration and exclusivity of breastfeeding, there is suggestion that prolonged breastfeeding may additionally reduce obesity.9 Dewey et al. found that breastfed infants were leaner at one year than those who were formula fed.10 Von Kries et al. found that infants who were exclusively breastfed for three to five months were 35% less likely to be obese when they entered school.11 Other studies have shown that infants who were breastfed for more than three months were leaner and showed a trend toward lower skin fold values, and that breastfed infants had more activity of their upper limbs which could contribute to their leaner body mass.12
In addition, there are studies in Native American children that show breastfeeding mitigates the development of type II diabetes at the time of adolescence.13 Babies who were exclusively breastfed for two months had significantly lower rates of type II diabetes in all age-groups. The odds ratio of developing diabetes for exclusively breastfed individuals was less than half of that in those exclusively bottle-fed. Evidence suggests that rapid weight gain in infancy—particularly during the first four months of life—is predictive of childhood and adult obesity. Breast-feeding may play a mitigating role by decreasing this early, rapid weight gain.14
Irregular Eating Between Two and Six Years
Between the ages of two and six years, children often develop irregular eating patterns. They may want small snacks frequently instead of three meals/day. They may have a variable intake from one meal or one day to the next. They may want to eat the same foods repeatedly and may refuse to try new foods. These behaviors may be explained by decelerating growth patterns; physical, emotional and cognitive developmental issues; and familial, cultural and social habits and norms.
The best way to prevent feeding problems is to teach children to feed themselves, and to offer a variety of healthy foods. To help avoid problems, young children should not be allowed to drink too much milk or juice, forced to eat when they aren't hungry, or to eat foods they find aversive. Avoidance of sweet desserts, soft drinks, fruit-flavored drinks, sugar-coated cereals, chips or candy will allow children to focus on foods with nutritional value.
In addition, fast food venues should be discouraged for young children. In a study of 6,212 children and adolescents, 4-19 years of age, 30% consumed fast food on a typical day. Those children eating fast food consumed on average an additional 187 kcal/day that had an adverse effect on dietary quality.15 It's also best to avoid giving young children sugar-containing carbonated sodas. Ample evidence is emerging that sugar-added soda consumption contributes to obesity with the odds of becoming obese increasing by 60% for each 12-ounce can of soda.16 Sugar-added soda intake begins early and increases throughout childhood with 3% of females and 7% of males six-to-eight years of age drinking three or more eight-ounce servings of soft drinks per day and 32% of females and 52% of males 14-18 years of age consuming such high quantities.17
If parents worry whether their young child is eating too little or too much, they should remember the concept of self-regulation. If allowed to decide when to eat and when to stop eating without outside interference, most children will eat as much as they need depending on the energy density of their diets. Although many parents or caregivers try to control the amount of food a child eats, recent research reveals that parents' restrictive feeding practices often do not improve their child's diets and can actually increase a child's susceptibility to becoming overweight.18
Children Need More Exercise
To stay in energy balance, young children need the opportunity to expend energy. The National Association for Sport and Physical Education (NASPE), the American Alliance for Health, Physical Education, Recreation & Dance (AAHPERD) and the American Academy of Pediatrics (AAP) recommend that young children participate in at least 60 minutes of moderate to vigorous physical activity a day.19,20
Becoming physically active early in life is essential to learn to move skillfully, ensure healthy development, and lessen the chance of developing sedentary habits and childhood obesity. However there is emerging evidence that more and more young children do not have adequate physical activity levels. Reilly et al. reported that three-year-olds had 20 minutes of moderate to vigorous physical activity a day, as assessed by accelerometry, compared to the desired 60 minutes.21 Study subjects were found to spend between nine and 10 hours of their waking day hardly moving at all.
Concomitant with this, there has been a reduction in physical education in school. In 2000, 8% of elementary school children had daily physical education (PE) classes, while 6% of junior and high school students participated in daily PE.22 In contrast, the average child watches more and more television every day—up to an average of three hours. This is exacerbated by the finding that 32% of two-to-seven year olds and 65% of 8-18 year olds have a TV in their bedrooms.23 In a study in Mexican American children, the risk of becoming overweight increased by 12% for each one-hour increment in daytime television watching and decreased 10% for each daily hour of moderate to vigorous activity.24
Consequences of Energy Imbalance
The consequences of being out of energy balance are already realized in early childhood. In 2002, the 22.6% of children two-to-five years old being overweight or at risk for overweight were disproportionately from racial/ethnic minority groups,25 The prevalence of overweight with BMI > 95th percentile was 8.6% for non-Hispanic white children, 8.8% for non-Hispanic black children and 13.1% for Mexican American children. High-risk subjects have a family history of type II diabetes. Children and youth who are overweight are likely to become obese adults. The probability of overweight persisting into adulthood increases from approximately 20% at four years to between 40-80% by adolescence.26
Obesity leads to serious medical, psychological and social problems during childhood. Childhood overweight is associated with a higher prevalence of risk factors for adverse health outcomes, such as insulin resistance, elevated blood lipids, increased blood pressure, and impaired glucose tolerance and type II diabetes. Other health consequences include asthma, gallbladder problems, sleep apnea, and psychiatric and psychological abnormalities.
•Insulin Resistance: Abnormally high levels of insulin have been found in toddler-aged children who are overweight.27 This is indicative of insulin resistance and over time can be associated with metabolic syndrome, polycystic ovarian syndrome, cardiovascular disease risk and diabetes. In Pima Indian children, hyperinsulinemia at ages five-to-nine years was positively associated with the rate of weight gain at follow-up an average of nine years later.28
Overweight children can progress from insulin resistance to impaired glucose tolerance (IGT), or what is now being called pre-diabetes. (Defined as two-hour post oral glucose load glucose level >140 and <199 mg/dl). Sinha et al. showed that 25% of obese children 4-10 years of age and 21% of obese adolescents 11-18 years of age have IGT.29 Similarly, Goran et al. reported IGT in 28% of overweight Hispanic youth with a positive family history of type II diabetes.30 The increase of cases of type II diabetes occur mainly in ethnic minorities including Mexican American, African American, and Native American.
- Cardiovascular Disease: Overweight children are at risk for high levels of cardiovascular disease (CVD) risk factors. Approximately 60% of obese children five to 10 years of age had at least one CVD risk factor such as elevated cholesterol, triglycerides, insulin or blood pressure, and 25% had two or more risk factors.31 As a result, atherosclerosis begins in childhood with the deposition of cholesterol and its esters, referred to as fatty streaks, in the vascular system. North American children as young as three years of age have been shown to have aortic fatty streaks.32 Fatty streaks and fibrous plaques are related to serum total cholesterol, LDL-C, and systolic blood pressure levels.33 The establishment of healthy nutritional habits and adequate physical activity early in life may prevent the development of fatty streaks and more advanced atherosclerotic lesions.
- Liver Disease: Abnormal liver-function tests associated with fatty liver have been seen in overweight children.34 Non-alcoholic fatty liver disease (NAFLD) is another co-morbidity of obesity. It is difficult to estimate the prevalence of this condition among obese children and adolescents. Typically there is elevation of hepatic transaminases, alkaline phosphatase and GGTP. Bilirubin, albumin and prothrombin may rise in the later stages of the disease process. A benign clinical course is typical of hepatic steatosis, however, non-alcoholic steato-hepatitis (NASH) can lead to fibrosis and cirrhosis.
- Breathing Difficulties: Asthma is seen more often in obese than in normal weight children. More boys are affected, as are nonallergic children, and overweight children use more medication, wheeze more and make more emergency room visits.35Obstructive sleep apnea is also seen in obese children. It is characterized by episodes of stopping breathing during sleep and causes snoring, mouth breathing, frequent awakening, and poor academic performance.
- Psychological Problems: Poor quality of life and low self-esteem are endemic among obese children. The prevalence of psychological problems in obese children may depend on the degree to which obesity is accepted by family members and the culture in which the child lives.36 The likelihood that a severely obese child or adolescent will have impaired health-related quality of life is 5.5 times higher than that of a normal weight child and similar to that of a child with cancer.37 Moderate to severe depressive symptoms (48%) and high levels of anxiety (35%) are reported in severely obese adolescents. These observations may relate to the fact that overweight adolescents tend to be more isolated from social networks. As a result, obese girls are more likely to have attempted suicide than non-obese girls. Other high-risk behaviors are also frequent among overweight compared with their non-overweight peers, including alcohol consumption, cigarette smoking and binge eating.
Promoting the concept of energy balance is critical if the epidemic of childhood obesity—which now encompasses young children—is to be reversed. Healthcare providers can help families understand the benefits of and the desire to establish healthy eating practices and physical activity patterns for young children. This will help prevent the short and long-term health risks of overweight and obesity. The focus should be to discuss this early, with prevention as the ultimate goal.
Francine Ratner Kaufman is Professor of Pediatrics at the Keck School of Medicine at the University of Southern California (USC). She serves as the Department Head for the Center for Diabetes, Endocrinology and Metabolism at the Children's Hospital Los Angeles. She is also past president of the American Diabetes Association and author of Diabesity: the Obesity-Diabetes Epidemic That Threatens America—and What We Must Do About It (Bantam, 2005).
Assisted by Shaloha Robin, a student at the University of Southern California and research assistant at the Children's Hospital in Los Angeles.
- Fagot-Campagna A. Emergence of type II diabetes mellitus in children: epidemiological evidence. J Pediatr Endocrinolg Metab 2000;13 (suppl 6): 1395-1340.
- ABC's of Good Nutrition For Young Children, Facts About Fitness. University of Massachusetts Extension School, Nutrition Program. 2005. http://k12s.phast.umass.edu/abc/unit1/facts_about_fitness.html
- Baranowski T, Bryn GT, Rassin DK, Harrison JA, Henske JC: Ethnicity, infant-feeding practices, and childhood adiposity. J Devl Behav Pediatr 1990;11: 234-239.
- Gillman MW, Rifas-Shiman SL, Camargo CA Jr, Berkey CS, Frazier AL, Rockett HR, Field AE Colditz GA: Risk of overweight among adolescents who were breastfed as infants. JAMA 2001;285: 2461-67.
- Hediger ML, Overpeak MD, Kuczmarski RJ, Ruan MJ: Association between infant breastfeeding and overweight in young children. JAMA 2001;285:2453-2460.
- Owen CG, Martin RM, Whincup PH, Smith GD, Cook DG: Effect of infant feeding on the risk of obesity across the life course: a quantitative review of published evidence. Pediatrics 2005;115:1367-1377.
- Savino F, Costamagna M, Prino A, Oggero A, Silvestro L: Leptin levels in breast-fed and formula-fed infants. Acta Pediatr 2002;91: 897-902.
- Dewey, KG: "Is Breastfeeding Protective Against Child Obesity?" Journal of Human Lactation, Vol 19, No.1 9-18 (2003).
- Burke V, Belin LJ, Simmer K, Oddy WH, Blake KV, Doherty D, Kendall GE, Newnham JP, Landau LI, Stanley FJ: Breastfeeding and overweight: longitudinal analysis in an Australian birth cohort. J Pediatr 2005;147: 56-61.
- Dewey KG, Heinig MJ, Nommsen LA, Peerson JM, Lonnerdal B: Breast-fed infants are leaner than formula-fed infants at 1 y of age: the DARLING study. Am J Clin Nutr. 1993;57:140-145.
- von Kries, Koletzko B, Sauerwald T et al.: Breast feeding and obesity: cross sectional study. BMJ 1999;319: 147-150.
- 2001 Swedish study, Articles from LEAVEN: Obesity and Infant Feeding Patterns, Linda N. Couvillion, Vol. 38 No.3, June-July 2002 p. 51.
- Pettit, DJ et al. Breastfeeding and Incidence of Non-Insulin-Dependent Diabetes Mellitus in Pima Indians. Lancet. July 19, 1997. 350(9072):166-168.
- Stettler N, Stallings VA, Troxel AB, Zhao J, Schinnar R, Nelson SE, Ziegler EE, Strom BL; Weight gain in the first week of life and overweight in adulthood. Circulation 2005;111: 1897-1903.
- Shanthy A. Bowman, Steven L. Gortmaker, Cara B. Ebbeling, Mark A. Pereira, and David S. Ludwig: Effects of Fast-Food Consumption on Energy Intake and Diet Quality Among Children in a National Household Survey. Pediatrics, Jan 2004;113: 112-118.
- Ludwig DS, Peterson KE, Gortmaker SL: Relation between consumption of sugar-sweetened drinks and childhood obesity: a prospective, observational analysis. Lancet 2001;357: 505-508.
- Fisher JO, Birch LL: Restricting access to foods and children's eating. Appetite 1999;32: 405-419.
- Krebs NF, Jacobson MS: Prevention of pediatric overweight and obesity. Pediatrics 2003;112424-430. AAP policy statement "Prevention of Pediatric Overweight and Obesity" aappolicy.aapublication/cgi/content/full/pediatrics;112/2/424.
- www.aahperd.org, the web site of the American Alliance for Health, Physical Education, Recreation & Dance (AAHPERD).
- Reilly J, Jackson D, Montgomery C, Kelly L, Slater C, Grant S, Paton J: Total energy expenditure and physical activity in young Scottish children: mixed longitudinal study. Lancet 2004;363: 211-212.
- Committee on Public Education. Pediatrics: 2001;107: 423-26.
- Nesmith J D: Type II Diabetes Mellitus in Children and Adolescents Pediatrics in Review 2001;22: 147-152.
- Hernandez B, Gortmaker SL, Colditz GA, Peterson KE, Laird NM, Parra-Cabrera S. Association of obesity with physical activity, television programs and other forms of video viewing among children in Mexico city. Int J Obes Relat Metab Disord. 1999;23: 845-854.
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- Guo SS, Chumlea WC. Tracking of body mass index in children in relations to overweight in adulthood. Am J Clin Nutr. 1999;70(suppl): 145S-148S.
- Hannon TS, Rao G, Arslanian SA: Childhood obesity and type II diabetes mellitus. Pediatrics 2005;116: 473-480.
- Odeleye OE, de Courten M, Pettitt DJ, Ravussin E. Fasting hyperinsulinemia is a predictor of increased body weight gain and obesity in Pima Indian children. Diabetes 1997:46: 1341-5.
- Sinha R, Risch G Teague B, Tamborlane WV, Banyas B, Allen K, Savoye M, Rieger V, Taksali S, Barbetta G, Sherwin RS, Caprio S: Prevalence of impaired glucose tolerance among children and adolescents with marked obesity. N Engl J Med 2002;14: 802-810.
- Goran MI, Bergman RN, Avilla Q, Watkins M, Ball GDC, Shaibi GQ, Weigensberg MJ, Cruz ML: Impaired glucose tolerance and reduced B-cell function in overweight Latino children with a positive family history for type II diabetes. J Clin Endocrinolo Metab 2004;89: 207-212.
- McGill HC, McMahan CA, Herderick EE, Malcom GT, Tracy RE, and Strong JP: Origin of atherosclerosis in childhood and adolescence. Am. J. Clinical Nutrition, Nov 2000; 72: 1307-1315.
- Institute of Medicine. Fact Sheet: Childhood obesity in the US: Facts and Figures. From: Preventing Childhood Obesity: Health in the Balance. Institute of Medicine, National Academies of Science. Washington, DC: National Academies Press; January 2005.
- Freedman DS, Khan LK, Serdula MK, Dietz WH, Srinivasan SR, Berenson GS. Inter-relationships among childhood BMI, childhood height, and adult obesity: the Bogalusa Heart Study. Int J Obes Relat Metab Disord. 2004;28(1): 10-16.
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- Belamarich PF, Luder E, Kattan M, Mitchell H, Islam S, Lynn H, Crain EF: Do obese inner-city children with asthma have more symptoms than non-obese children with asthma? Pediatrics 2000; 106(6): 1436-1441.
- Strauss RS: Childhood obesity and self-esteem. Pediatrics 2000;105(1): 1-5.
- Schwimmer JB, Burwinkle TM, Varni JW: Health-related quality of life in severely obese children and adolescents. JAMA 2003;289: 1813-1819.