Breastfeeding, fitness & baby’s weight


A subscriber to my newsletter, Jenine wrote to me and asked if I had any nutritional advice for “athletic mothers who are breast-feeding”? Is there anything more beyond the advice to eat healthy? Breastfeeding itself certainly requires extra energy, that is, providing liquid food for someone else means you need to eat and drink more. Approximately 2900 kJs (700 Cals) are needed to produce a litre of breast milk. That has to come partly from Mum’s diet and partly from the 3-5kg of extra body fat laid down during pregnancy. Some women lose the extra body fat quickly, some slowly, but keeping active will certainly help.
Vitamin D
During the winter especially, lactating Mum’s may need some extra vitamin D as a supplement, through vitamin D fortified foods or mushrooms exposed to light. Vitamin D is needed to assist calcium absorption from the gut. Nowadays many women are assessed for vitamin D levels during pregnancy because of a rise in infant rickets in modern societies. Women who are dark skinned, indoors during the middle of the day or live further from the equator will be most at risk.
Although the baby sucks 260 mg of calcium out of Mum each day, much of it coming from Mum’s bones, taking extra calcium does not stop this bone loss, with the losses being replaced after weaning. (I didn’t know that until I just read it in a textbook). For this reason breastfeeding Mum’s don’t need to fret about taking more calcium than usual (assuming they eat calcium-rich foods like cheese, yogurt, milk, soft bones of fish, calcium-fortified soy drinks).
Most other nutrients are required in greater amounts but this is usually covered by the extra appetite from being active and producing milk.
Eat well, eat a bit more & keep active
Anyway, there is nothing unique in the advice for very active breast-feeding Mums, except to eat well and eat more. Remember that in the olden days you may have had a “day off” for the birth, then you were back out gathering and cooking so lactation was always associated with being active. If you do find weight loss after birth to be a bit too rapid, then nourishing drinks (eg Sustagen), smoothies with extra skim milk powder added or including more oil (eg olive oil) in your diet will pump up the kJs/Cals.
Breastfeeding & baby’s weight
Jenine then further asked if childhood obesity and breast-feeding were linked. She had heard that obesity can begin through mother’s milk. I assumed that she was referring to a preventative, not causative, role. My local legend, Professor Wendy Oddy, University of Western Australia, wrote a review of all the information on this very topic. In one sentence, breast-fed kids have a lower risk of being overweight as they grow up. The “why” is interesting.
1. Breast-fed kids drink until they are done. Mouth off breast signals to Mum that they have had enough (infant-regulated). Bottle-fed babies may be encouraged to finish the bottle (parent-regulated).
2. Bottle-fed babies grow at a faster rate, effecting adipokines, which in turn affect insulin sensitivity and create a chronic sub-inflammatory state playing a role in heart disease and diabetes development.
3. The Growth Acceleration Hypothesis states that rapid early weight gain may program the body for later obesity, high blood cholesterol, high blood pressure and insulin resistance (which means high blood glucose levels). Breast-fed babes seem to gain weight slower in later infancy, suggesting that breastfeeding for a year or so could protect baby from later flab and disease.
4. The Early Protein Hypothesis view is that the higher protein content of formula could be responsible for an increased infant growth rate and excessive production of permanent fat cells. Breastfeeding protects against fatness with lower blood insulin, less fat storage and preventing fat cell development.
What does it all mean?
Breast milk has all that a newborn requires and it is smart to exclusively breast feed for the first six months and continue breast feeding for the following six months while introducing solids. Baby learns to feed on demand and stop when content, normalising both appetite and growth. The pay-off seems to be a healthier and leaner child down the track. Good news. If only it could make them immune from drug dealers, charlatans, television viewing, advertising and religious fundamentalism too.
Reference: Oddy WH. Infant feeding and obesity risk in the child. Breastfeeding Review 2012; 20 (2): 7-12

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