when to wean

Question 1

why and when infants wean

Answer 1

• Major developmental change
• Milk → solids
• Sucking → chewing/ biting
• Dependent → independent
• When are infants weaned?
• Milk energy supply cannot satisfy infant or provide
  nutrients
• Motor skills are developed sufficiently
• Major variability
• Thailand: 15% some solids at 2 weeks
• UK: 3% some solids at 6 weeks

WHO (2001) recommends weaning at 6 months
* UK Department of Health adopted this in 2003
Reality in the UK:
* 30% introduced solids by 4 months
* 75% introduced solids by 5 months
* 94% introduced solids by 6 months
(2010 Infant Feeding Survey, DoH, 2013)

Question 2

oral motor skills and gag reflex

Answer 2

*Oral motor skills necessary for weaning
* Highly complex: swallowing = 31 muscle pairs
* Delayed transition to solids - miss this
developmental period → problems
* Anxieties about choking can delay transition
* Aspiration can result
* accidental ingestion of food or fluids into the lungs
if too much of a delay (8,9 months)- you miss the window of opportunity for development
- we see this delay because of anxieties

GAP REFLEX- Adaptive – prevents choking
* Common in the transition period
* Not serious – but caregivers can panic
* Gagging: retch and make a lot of noise
* Choking: will be silent
* Can become hypersensitive
* Learned from negative experience - e.g., choking
* Generalises to all foods, even sight of food
* Professional help required to ‘unlearn’ response

Question 3

learning what to eat

Answer 3

• Need to distinguish non-edible substances
  *Sensory qualities of food
  *Anticipated consequences of eating food
  – e.g., poisoning
• Cultural beliefs
  *Disgust
  *Disease
  *Pica – eating non-foods

Neophobia = ‘fear of the new’
* New and previously liked foods
* Decreases with age
* 69% 2-year-olds refuse to taste new foods
* 29% 3-year-olds
* <1% 5-year-olds
* 10-20 tastes needed before may ‘like’ food
* Exposure during weaning sets foundation
* Breastfeeding and exposure

Question 4

critical period in weaning?

Answer 4

• Fewer exposures needed over weaning period
• Birch et al. (1998): 1 exposure = 50% increase in intake
  in 4–7-month-olds
• More exposures needed after weaning

BUT not critical period because…
* Older child/adult will accept novel food eventually
* Continued cognitive development influences
further acceptance
* Information on healthiness, for example, can
influence intake

Question 5

food preferences and how much to eat

Answer 5

Children prefer
* Sweeter tastes
* Familiar foods
* Greater post-ingestive feedback
* Children dislike
* Bitter tastes
* Tastes associated with illness
or treatment (e.g., cancer)
* Less post-ingestive feedback

• Infants and young children very good at
  self-regulation
• Early models based on homeostatic principles
• Motivated to maintain absence of hunger
• Eat until homeostasis is restored

Question 6

how much to eat and eating in the absence of hunger

Answer 6

Birch and Dysher (1986)
* 2–5-year-old children
* High or low energy preload snack;
40 kcal vs 150 kcal
* Lunchtime energy intake measured
* Compensation very accurate in lOW OF HIGH CAL SNACK
* More accurate than adults

Birch et al. (2003)
* Eating in the Absence of Hunger (EAH)
increases from 5-9 years

*Rolls et al. (2000)
* Macaroni cheese offered in different portion
sizes
* 2-3-year-olds eat approximately same
* 4-6-year-olds eat +60% if portion size doubled
by age of 4 we are already influenced by external stimuli such as portion sizes
suggests portion sizes for children is very important (parental influences, giving your children large sizes means they will eat it even if they are full due to unit bias… a environemtnal reason obeses parents have obese kids?