Why would a baby put on loads more weight when switching from breastmilk to formula?

[Caz10]

This is just curiosity - a colleague of my sisters has a 5mth old baby who has been exclusively breastfed until now, but who has had terrible reflux. The mother has been advised to switch to formula, which she was quite happy to do, and baby's reflux is now much improved, and her weight has absolutely shot up, more than triple in a week what it has previously been. Everyone very happy at baby putting on more weight, but I thought it sounded a bit unhealthy to gain so much so fast.

I breastfeed my dd who was a very slow weight gainer to start with, so not v knowledgeable about formula - is it massively more calorific? I never knew this and just wondered, thanks!

Formula and breastmilk are about the same in terms of calories.

But maybe the baby is taking more formula than he did breastmilk.

You are right. This is not necessarily a good thing. But who knows, in an individual case, if he would have gained the same on breastmilk if it had gone better?

However, the physiological pattern is for weight gain to slow down from about 5 mths.

Thank you tiktok

(and as an aside, would also like to say thank you for the wonderful advice you gave me when I was struggling with dd and pressure from HVs etc to put her on formula - she did end up being mix-fed when I went back to work at 9mths but we are still happily feeding at 16mths )

I suspected maybe the baby wasn't taking on as much breastmilk for whatever reason. As I said everyone happy re the weight gain, maybe it will slow down a bit, but I was just a bit . TBh I think she has been given some v poor BF advice, but they are all just relieved that the reflux has improved so I am keeping my nose out!

Glad I helped you, Caz

Massively, thank you!

DD was born teeny tiny 5lbs ish, slow (but steady ) weight gain and tootled along the 0.4th centile - I never weigh her now but when she got her MMR she got weighed and was on the 75th and it was SO satisfying to tell the HV we never caved to her pressure followed her advice!

No...actually breastmilk is slightly higher in calories than most formulas. However, breastfed babies tend to take in what they need, whereas formula fed babies run the risk of being encouraged to "finish just this last bit" on a fairly regular basis.

Around the 5 month mark is when many formula fed babies will start to put on the weight naturally...one difference being the make-up of the body fat as opposed to that of a breastfed baby.

Was there any concern with her weight while being breastfed? If the breastfeeding was not as efficient as it could have been, that could be part of the reason as well. Whether the formula had anything to do with the refux would be difficult to tell....might have been something in the mother's diet while nursing that was a contributing factor, might be that many babies naturally outgrow reflux after several months.

The slower weight gain, at least in the beginning, and being able to determine for themselves how much to take in, is one reason why babies who have been breastfed for a substantial period of time are thought to be less likely to have weight issues in later years. Of course there will always be exceptions....

Thank you! There were concerns re weight before - now it seems only i am concerned!

i have a theory about this

ds2 is 2 months and the ff mothers on my PN thread are giving between 4-6oz of f per feed, ds2 is taking far more bm than this as i can express 4oz of bm in 5 mins and still have loads of milk left. he feeds for 1/2 hour or more at a time every couple of hours.

if he were to switch to ff and be taking in the same amount of ff he'd be taking 3 or 4 times as much as other ff babies his age and probably shhot up in weight.

Not sure about the question but my DS has severe reflux and is excl bf. He has tried formula and thickened feeds, both made it worse overall. Some reflux babies do well on the thick feeds though or maybe the baby is on a hypoallergenic feed like Neocate or was having latch issues.

If there were weight issues before and he had reflux which is now sorted it could be simply that he is now feeling much better and experiencing a period of catch-up growth prior to settling down to again to a more "normal" pattern of weight gain. Rather like when you've been ill many people get ravenously hungry for a few days after and regain any weight lost whilst ill, he's just re-finding his natural growth curve.

Aaah that's interesting AM, hadn't thought of it like that! Maybe the weight gain will settle down after that initial burst then.

It could also be that her breastmilk had reduced in quality over the last few weeks so the baby wasn't getting much nutritional value.

That happened to me when DS was 5 weeks old and my milk eventually dried up whilst I was still trying to feed.

I remember how he guzzled down his first formula feed and then slept for hours. Poor little bugger must have been starving!

Guess my all natural 32GG norks were only intended to be decorative rather than functional!

Technofairy - breastmilk does not reduce in quality and its nutritional value remains high throughout the time bf continues.

There may have been reasons why bf did not work out for you, and that's sad for you and your baby but the quality of your breastmilk will not have had anything to do with this.

Yeah, breastfeeding didn't work out for us because he wasn't getting anything from my milk! I was expressing as well so I know the milk was there, quantity wasn't a problem then, but he was constantly hungry.

Surely I can't be the only woman ever whose milk wasn't sustaining her baby after the first few weeks?

Technofairy - the research on this is conclusive: breastmilk is consistent in quality. What can be affected is volume - mothers are not consistent in the quantity they produce.

We can discuss this more if you want.

Happy to discuss it but not if you're just going to keep telling me I'm wrong! I know this is what happened to me, as did the consultant and HV, you have your own view so we may just have to agree to disagree.

But I've just read a very interesting BMJ article about breast milk and how the quality of it, and in particular fat content, varies not only from woman to woman but that the quality of a woman's milk can vary dependent on the time of day. The study was in the UK and in respect of donor breast milk for prem infants.

"Several milk samples did not contain
enough fat to supply even a fraction of the recommended energy requirements of these infants." That would be me then. The research recommends that donor breast milk is quality controlled.

So, if fat content can plummet depending on the time what is so unusual about the fat content of my milk not returning to normal? Surely any normal process in the body can go wrong or become less effective at any time. Why is breast milk production exempt?

I think the statistic is that a FF baby from birth consumes on average 30,000 more calories by the time they are 8 months old.

Thats not the milk calorie content but the fact that on average FF infans consume more milk and more quickly.

Formula milk also has a different protein and growth hormone content. It is much higher in protein for example which can encouage growth. It als has different levels of other hormones which can affect growth.

As breast milk changes so much throughout each feed and over the course of a number of feeds breastfed babies get very good at sorting their own intake out - formula feeds are very similar so less of a chance to learn this.

THis isnt to say that a FF baby is doomed lol - just you need to be aware of their fullness signs etc, feed on demand etc.

Am a semi expert on this after just writing up my phd on the very subject

that is really interesting peppapighastakenovermylife (she can't have done entirely eh?). can you shed any light on my question here?

technofairy, as i understand it, bm is what it is. do not understand why being larger in volume would make it less worthy. i don't think fat content can plummet, how would that happen?

am not attacking, just don't see how this could be.

oh she has fishie lol - she dictates my every waking hour lol.

am a bit sleep deprived but whats your question lol

Also it is natural for babies to put on fat before they become mobile. If babies don't do this they end up plummeting down the centiles when they become mobile and struggle to put on weight because they physically can't consume enough calories in food at 1yr
If LO was on a low centile it is possible that ff has just jumped baby to the natural centile for height iyswim I have no doubt that even if it continues to increase rapidly, it will drop off once mobility kicks in

[dh looks rather like daddypig heehee]

i was asking about technofairy's post. if bm quenches thirst in hot weather etc and cluster feeding never empties supply....

then there must be a bit of difference in the dilution no?

No worries, the research is here ukpmc.ac.uk/articlerender.cgi?artid=677813. The PDF doc has the detail.

According to this the fat content in bm can vary widely according to the time of day. Apparently very early morning milk has a lower fat content. I've no idea how this happens but it would seem that it does.

I appreciate that this could be old, disproved research however.

It was tiktok who mentioned volume not me. I don't think she was saying that greater volume means poorer milk, just that some women don't produce consistent amounts of milk.

Well breast milk does differ in fat volume across the course of a day and across the course of a feed. That doesnt mean to say it is too low at any point of the day just that it provides different levels at different points. If you think about it we eat and drink different things depending on how thirsty or how hungry we are.

I am not aware of any research that shows that breastmilk doesnt have enough energy content in it for some mums (although more than happy to be proved wrong). I know there is evidence that it varies from mum to mum though as studies have shown that babies who have mums who produce milk of a higher fat content feed for a shorter period of time. Most studies show that breast milk is pretty similar for most mums - at least in the first 6 months - there can be more variability after that. However that is most mums - perhaps it could differ for some mums.

I havent had time to read that paper properly but prem babies and prem milk is a different matter to full term babies really. Also, from the skim read I just had it says that milk varies in fat volume over the course of a day so I guess if one mum pumped at her low fat time or pumped lots of foremilk and just that was given to a prem baby then it wouldnt be high enough in fat. Thats why they pool all the milk together.

Techno - I am really sorry to hear you had a tough time. I hope you are ok about it now

My research expertise is in the analysis of biological samples (predominantly but not exclusively blood and urine) and certainly there is a compositional difference in most body fluids dependent on a whole host of factors including time of day and collection method. It would therefore not surprise me to find diurnal variation in breastmilk composition. I admit however that I have not (yet) analysed breastmilk, (though have been considering it).

Oooh fancy a joint research project academic mum (completely hijacking thread sorry!)

Thanks Peppa - I'm fine about it. At least I got a good 4 weeks in which is better than nothing.

The irony though, having ginormous boobies and having to formula feed. I can see the funny side