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Energy intake, not energy output, is a determinant of body size in infants
A J Stunkard1, R I Berkowitz, V A Stallings
1Department of Psychiatry, School of Medicine, University of Pennsylvania, Philadelphia 19104-2648, USA. stunkard@mail.med.upenn.edu
Insights
Infant body weight at one year is primarily determined by early food intake and sucking behavior, not parental obesity or energy expenditure. These factors significantly influence weight and body composition in early childhood.
Area of Science:
- Pediatrics
- Human Nutrition
- Childhood Obesity Research
Background:
- Parental obesity and low energy expenditure are hypothesized determinants of infant body weight.
- Understanding early determinants of body weight is crucial for preventing childhood obesity.
Purpose of the Study:
- To assess the relative contributions of genetic background, energy intake, and energy expenditure on infant body weight at one year of age.
Main Methods:
- Studied infants of obese and lean mothers, assessing risk factors at three months.
- Measured energy intake, nutritive sucking, and energy expenditure over three days.
- Analyzed correlations between early measures and body weight at twelve months.
Main Results:
- Infant weight at 12 months was significantly predicted by weight at 3 months (41%), nutritive sucking (9%), food intake (8%), and male sex (3%).
- Early food intake and sucking behavior correlated with weight-for-length, body fat, and fat-free mass at 12 months.
- Contrary to hypotheses, maternal obesity and energy expenditure did not predict body size at 12 months.
Conclusions:
- Energy intake is a significant contributor to infant body weight and body composition at one year.
- Parental obesity and energy expenditure do not appear to be significant determinants of infant body weight at one year.
Background:
It has been proposed that the primary determinants of body weight at 1 y of age are genetic background, as represented by parental obesity, and low total energy expenditure.
Objective:
The objective was to determine the relative contributions of genetic background and energy intake and expenditure as determinants of body weight at 1 y of age.
Design:
Forty infants of obese and 38 infants of lean mothers, half boys and half girls, were assessed at 3 mo of age for 10 risk factors for obesity: sex, risk group (obese or nonobese mothers), maternal and paternal body mass index, body weight, feeding mode (breast, bottle, or both), 3-d energy intake, nutritive sucking behavior during a test meal, total energy expenditure, sleeping energy expenditure, and interactions among them.
Results:
The only difference between risk groups at baseline was that the high-risk group sucked more vigorously during the test meal. Four measures accounted for 62% of the variability in weight at 12 mo: 3-mo weight (41%, P = 0.0001), nutritive sucking behavior (9%, P = 0.0002), 3-d food intake (8%, P = 0.0002), and male sex (3%, P = 0.05). Food intake and sucking behavior at 3 mo accounted for similar amounts of variability in weight-for-length, body fat, fat-free mass, and skinfold thickness at 12 mo. Contrary to expectations, neither total nor sleeping energy expenditure at 3 mo nor maternal obesity contributed to measures of body size at 12 mo.
Conclusions:
Energy intake contributes significantly to measures of body weight and composition at 1 y of age; parental obesity and energy expenditure do not.