Breastfeeding versus formula feeding: The postnatal weight loss debate

Breastfeeding in the media

 

You don’t need me to tell you that breastfeeding is a hot topic in the media. Only in the last few days there has been a raging debate on facebook – perhaps you took part in it – surrounding a story posted by a breastfeeding woman saying she had been shooed out of a clothes chain store for breastfeeding. Indeed, over the last 12 months or so, there has been a huge amount of high profile coverage of breastfeeding, from the glamorous front cover of Elle Australia featuring model Nicole Trunfio feeding her son Zion, to images of celebrities sharing their breastfeeding photographs on twitter. There have also been countless blogs on the topic, ranging from numerous articles in BBC online, to the Huffington Post, and – I can vouch for it – a never ending succession of posts on facebook. It is noticeable that whenever I put up breastfeeding posts on facebook it is a bit like stirring a hornet’s nest – the debate is heated, feelings run high, and opinions are divided.

Losing the baby weight

 

Another topic that tends to cause a good deal of interest is losing the post-pregnancy baby weight. I wrote a piece recently with my key steps to follow for successfully ridding oneself of baby weight in a manner that is safe, sustainable and which actually works – the response was phenomenal. If you missed it, you can read it again now. Quite often these two topics – breastfeeding and baby weight loss – are discussed hand in hand. One of the best things about my job is getting to chat to all the lovely mums and mums-to-be in my classes every week, and I can tell you that breastfeeding, and its perceived effects on weight, are a common topic of conversation, and – once again – opinions are divided, as can be seen from these quotes taken from my facebook page:

“I’m nearly 4 months into breastfeeding my newborn and breastfeeding has been great for my figure! I’m skinner now than I was before I actually became pregnant!”

“Breast feeding did nothing for my weight loss - in fact it made me hungrier!”

“The weight fell off me when breastfeeding my second baby. I was hungrier and ate loads, but the weight dropped straight away. I actually put weight on once I finished feeding Teddy at 12 months old.”

 

“I breastfed my son and continued to put weight on. Once I stopped feeding I started losing it and I still am now.”

 

What are your experiences of feeding and postnatal weight management?

 

So I’d like to ask you what are your experiences of postnatal weight loss and feeding your baby?

  1. Perhaps you formula fed and lost lots of weight?
     
  2. Did you mix feed and if so what were your weight loss experiences?
     
  3. How about if you exclusively breastfed? Did this make you hungry and crave all the wrong sorts of foods? Or perhaps it encouraged you to think about what you were eating in the interests of your baby’s growth

    And here's a controversial question for you...
     
  4. What if your health care professionals had told you that breastfeeding exclusively for 6 months was the ultimate post-pregnancy weight loss tool?
  5. Would this have motivated you?
  6. Or would it have been  an interesting added bonus but otherwise irrelevant?  

Does breastfeeding really aid postnatal weight loss?  
 

Up to now I’ve given you anecdotes about feeding and weight loss but what are the research-based facts? There have been numerous large-scale studies comparing the impact of breastfeeding, formula feeding and mixed feeding on postnatal weight loss. By large-scale I mean that the samples have consisted of 1000s of women and that conclusions can, therefore, be drawn. Rather than trawling through all the science, I’m picking out some key points which I hope you will find both interesting and useful. Hold tight…

  • Exclusively breastfeeding for at least 6 months has the greatest impact in terms of losing weight post-pregnancy
     
  • The weight loss amongst those who are exclusively breastfeeding tends to occur after the 3 month postnatal threshold. It is believed that this is because new mums are quite sedentary in the very early weeks as they get used to feeding. As their activity levels start to pick up, the weight loss increases.
     
  • Mixed formula and breastfeeding has the second most impact in terms of postnatal weight loss.
     
  • Fully formula feeding leads to the lowest levels of postnatal weight loss
     
  • As you will know, the estimate is that fully breastfeeding requires approximately 500kcal per day. This energy requirement can be met in three possible ways:
     
  • You can eat more – I hear lots of mums say “yippee! More cake!”
  • You can become less physically active, thus conserving energy
  • You can use your body’s fat stores.
     

So let us look at these three suggestions more carefully because I believe them to be really important. The first suggestion is that one should consume an extra 500kcal but there is an assumption hidden within it. This assumption is that women are currently not over-eating and are keeping within their approximate 2000kcal/day allowance. Many of us don’t, hence why we put on weight. So if, for argument’s sake, a breastfeeding mama were already consuming 2500kcal and is now told to increase by 500kcal, that brings the daily calorie intake to 3000kcal. You can see where I am heading in terms of weight gain consequences.

 

The second suggestion is to be less active. Research highlights the fact that, not surprisingly, women in the very early postnatal weeks tend to be relatively inactive as they are spending a good deal of time feeding and generally getting used to looking after their little one. But once the GP has given the green light for physical activity and a new mother feels ready to exercise, it should only be encouraged, as it is health both for body and for mind.
 

Finally, it is suggested that the extra 500kcal energy requirement can be retrieved from maternal fat stores i.e. the body fat that we carry on ourselves. A recent research study concludes that amongst women who are clinically overweight, it is safe for both mother and infant if the mother restricts calorie intake by 500kcal/day. This will lead to a steady weekly weight loss of 0.5kg and will have no negative impact on the growth and wellbeing of the baby. Conversely, it is quite clear that if a woman is exclusively breastfeeding and is either underweight or at the low end of the healthy weight range, and does NOT increase her calorie intake, then she will start to lose too much weight.
 

  • Interestingly, research into the effects of moderate aerobic and/or resistance exercise alongside exclusive breastfeeding shows that postnatal weight loss does not increase with the addition of exercise. However, the combination of exclusive breastfeeding, moderate exercise for 45 minutes 4 times a week, and a daily calorie restriction (only for women in the overweight category) of 500kcal is the best weight loss strategy.
     
  • Having said this, following a postnatal cardio and resistance programme has been shown to improve fitness levels, insulin response to meals, and HDL cholesterol levels.
     
  • Breast milk volume and composition is not altered by moderate exercise. Only extremely vigorous exercise will affect the flavour of milk for approximately 1 hour after exercising – this is caused by a build-up of lactic acid.
     
  • The greatest predictor of getting back into shape postnatally is what shape you were in pre-conceptually. Research shows that those who are a healthy weight on entering pregnancy will lose the pregnancy weight more quickly than those who entered pregnancy in poor shape. The latter group will subsequently tend to retain more weight post-pregnancy and for a longer period. So the message is clear: try to improve fitness levels, eat healthily and attain a healthy weight prior to conceiving.

A twist in the story

 

So, from the research discussed so far, the case would appear to be clear cut: exclusively breastfeed for at least 6 months and you are onto a weight loss winner!

 

Rarely, however, are things so straightforward.

 

As you may have noticed, the discussion up until now has revolved entirely around weight and weight loss but nothing has been mentioned about body composition: lean body mass versus body fat.

 

And here is the sting in the tail of this story:

 

Studies focusing on body composition among breastfeeding women would seem to indicate that whilst much of the baby weight is lost among breastfeeding women, body composition would also appear to have changed…

 

…. but not for the best…

 

… with an increase in body fat at the expense of lean mass.

 

It has been suggested that this is a rainy day fat store for breastfeeding but the interesting thing is that studies show that even in countries with malnutrition, women retain an increased level of body fat.

 

This extra fat sticks until breastfeeding is stopped.

 

When you eat, your body has to process and store your food and this uses energy – a process called diet induced thermogenesis. It would appear that during breastfeeding, a woman’s body becomes energy efficient and uses less energy to process food. This, in turn, leads to the storing of a certain amount of extra body fat, until breastfeeding comes to an end.

 

All I can say about this is “Don’t let it put you off!”

 

This is a temporary situation and when the day eventually comes to stop breastfeeding, this relatively small amount of excess fat will quite simply go.

Last word

 

I have a very personal interest in breastfeeding in that I clocked up 5 years of breastfeeding my three children. I was lucky because I found it easy and this, with hindsight, made me rather smug. Since specialising in the field of pregnancy and postnatal fitness, I have worked alongside hundreds of mothers and my views have shifted dramatically. Becoming a mother is one of the greatest challenges women will ever experience in their lives and it is not always straightforward. New mothers have to adjust to a life that has been turned completely upside down: careers frequently suffer; postnatal depression and anxiety are not uncommon; breastfeeding does not always come “naturally” and this can lead to unwarranted feelings of guilt; societal pressures are such that women are expected to shrink back into their pre-pregnancy clothes within weeks and look immaculate, all whilst surviving on not much sleep; and family structures have changed to such an extent that most new mothers no longer have the support network of extended family living nearby.

 

So as mums, let’s all be kind to ourselves.

 

Let’s ditch the guilt trip.

 

Let’s bin the image angst.

 

Let’s eat good food that is also good for us.

 

Let’s exercise because it is fun.

 

Let’s breastfeed if we can and we wish to.

 

Let’s not breastfeed if we can’t or we choose not to.

 

Let’s not judge.

 

Let’s support.

 

United we stand.

 

     

Dr Joanna Helcké specialises in pregnancy and postnatal fitness, won the 2014 FitPro award of Excellence in Fitness and is a regular contributor to the national media. She is the creator of the UK’s first week by week online pregnancy and postnatal fitness system, is currently writing a cook book, and is also working on an exciting (secret!) product for pregnancy and new mum fitness!