The timing of solid introduction in an 'obesogenic' environment: a narrative review of the evidence and methodological issues

Aust N Z J Public Health. 2015 Aug;39(4):366-73. doi: 10.1111/1753-6405.12376. Epub 2015 Jun 11.


Objective: To evaluate the evidence for association between obesity risk outcomes >12 months of age and timing of solid introduction in healthy term infants in developed countries, the large majority of whom are not exclusively breastfed to six months of age.

Methods: Studies included were published 1990 to March 2013.

Results: Twenty-six papers with weight status or obesity prevalence outcomes were identified. Studies were predominantly cohort design, most with important methodological limitations. Ten studies reported a positive association. Of these, only two were large, good-quality studies and both examined the outcome of early (<4 months) introduction of solids. None of the four good-quality studies that directly evaluated current guidelines provided evidence of any clinically relevant protective effect of solid introduction from 4-5 versus ≥6 months of age.

Conclusion: The introduction of solids prior to 4 months of age may result in increased risk of childhood obesity but there is little evidence of adverse weight status outcomes associated with introducing solids at 4-6 rather than at six months.

Implications: More and better quality evidence is required to inform guidelines on the 'when, what and how' of complementary feeding.

Keywords: complementary feeding; developed countries; narrative review; obesity.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Breast Feeding*
  • Child Development
  • Female
  • Growth
  • Humans
  • Infant
  • Infant Food*
  • Infant Nutritional Physiological Phenomena*
  • Male
  • Pediatric Obesity / prevention & control*
  • Time Factors
  • Weaning*