Dr. Jay Wortman and his wife had their daughter while low carbing and he blogged about it all here:
http://www.drjaywortman.com/blog/wordpress/2010/09/12/low-carb-baby-trial-n1/

more recent post, but he isn't posting much recently.
http://www.drjaywortman.com/blog/wordpress/2013/02/07/and-shes-off-the-tether-that-is/

re: breastfeeding, be vigilant about drinking lots of fluids to keep your milk production going! and rest up as much as you can, stress will cause your milk production to fall. Also nurse (or pump) often, as that will cause you to produce more. Good for you and your baby and toddler -- is that two?! hugs to you for being a great mom.

Thank you all for the replies. I actually nurse my toddler and pump for my infant, who is unable to latch. So I will be aware of any change in out put (why I'm willing to "risk" it). I have plenty of milk frozen if my supply suddenly tanks, to last while I rebuild. I'm going to give it a go, thank you for the articles.

I meant, why are you willing to risks the baby's health? I am not talking about milk production, I am talking about how that type of diet may have an effect on the milk in general. How does that affect the baby's health? There is a story of this vegan family that had a baby. They fed the baby vegan food, it died.

How does feeding a baby vegan food compare with a baby drinking breastmilk? Answer: It doesn't.

I breastfed 4 children. The youngest I breastfed while on a low-carb/diabetic diet (lingering gestational diabetes.) I would say I had under 100g carbs daily. I had no issues with milk production. He breastfed until he was almost 2. He is now a healthy and smart 3-year-old.

They do compare very well. A mother, who has no idea what effect her choices will have on a baby. A vegan mother feeding her baby vegan food. What is the effect? Who knows.

A mother breast feeding her baby while she is on a low carb diet. What are the effects? Who knows... There is no research that I am aware of on this subject.

There is, in fact, a huge difference between feeding a baby "vegan food" and breastfeeding. When breastfeeding, the mother's diet affects the composition (ie - more coconut in mom's diet = more lauric acid in breastmilk, more fat in mom's diet = higher levels of fat in breastmilk), but as long as the proper vitamins and minerals are in mom's body, the milk will have the nutrients it needs to feed baby (even at the expense of mom's health; this is why most western women get cavities after having a baby - their bodies leach the minerals from mom to supply baby).

Feeding a young child a vegan diet is dangerous because a vegan diet is inherently nutrient deficient (even when done "right"), particularly in fats (especially saturated fats, which are needed for healthy development) and B vitamins (needed for everything).

A decent LCHF diet is arguably healthier than the standard American/western diet. Do some research to ensure you're getting enough nutrients, sure, but LCHF isn't inherently nutrient deficient or dangerous.

OP - Check out Christine Cronau. She and her kids eat LCHF and have done phenomenally well.

How would feeding a baby food designed by nature to feed babies compare to feeding a baby food not designed by nature to feed babies? Suddenly, by still consuming the same foods, just in a different ratio, the action suddenly causes milk production, something that has been done by the human animal for 10,000 years, to change to the point of harming the child's health? I'm pretty sure that in some cultures of the world there were diets naturally low-carb and they didn't die out.

I think it is ridiculously alarmist to suggest that the OP is taking her child's life into her hands by feeding the child milk produced by her body specifically designed for feeding infants. I assure you the milk isn't poisoned. The OP said she has breastmilk reserves if the baby looks like it's having issues. But as long as the mother stays healthy, the milk quality should remain sound.

My 3-year-old is taller than most other 3-year-olds and is wicked smart. He nursed longer because I let him. Other than that, he didn't nurse differently than my 3 others. He was as healthy as the rest of the lot. Is that because he breastfed? Maybe, maybe not. Is that because he breastfed while I was low-carbing by order of a doctor? No, I think he just got healthy breastmilk and genetics has done the rest. There's been no research on that, but I assure you he is fine.

OP sounds like she is on top of it and using a good and cautious approach to the situation. I don't think she'll have any issues.

I am sure that was the logic of the vegans. "These foods are natural, they are designed for humans, it's okay for the baby to eat it." We already know the end result. If you are not 100% sure of the consequences on the child, why even risk it? You know that when women eat fish mercury can be excreted in to the breast milk? Well methyl mercury. I am majoring in biochemistry, I can tell you this. Methyl Mercury is a weird compound, I can't even fathom the effects of it.

I am also sure there are cultures who didn't eat much meat and breast fed their babies, cultures that where more towards vegan. The vegans can use that logic too as you just did. Once again, we know the result.

Breast milk is mostly composed of lactose(milk sugar partially made from glucose(carbs)) and fats. Take note, glucose(carbs) is mostly what the breast milk is made of. Now if someone is on a low carb diet(lacking carbs) and breast feeding what are the effects?
The glucose can go to the child mostly which can cause problems for the mother, or it can go to the mother causing problems for the child, or it can be divided between the 2, the mother and the child.

Once again, why even take a chance? Why even risk it if you're not 100% sure of the effects? Your child seems healthy which is good. But what are the long term effects if any? Once again, it's a chance people are taking with the health of themselves or their child. In your case it's understandable due to your medical issues. But others who have no medical issues??? Like women who try to do a reduce calorie diet while breast feeding, it's just dumb. There are various reasons people do a low carb diet. The OP's reasons, I don't know why. But most of the time, i'd estimate 90% of the time people do it as a fat loss method. What's more important a babies health or you losing fat? As I said, it's just not the brightest idea.

It is widely accepted that the macronutrient composition of the mother's breastmilk is affected very little, if at all, by the mother's dietary intake. Similarly, vitamin deficiency in the mother does not cause deficiency in the milk. The mother ingesting a poison (mercury as you mentioned) is not the same as the mother eating less carbs. Eating a different macro of carbs isn't going to make poisons in the milk. While I agree decreasing calories significantly during pregnancy isn't a good idea, it isn't because it will affect quality of the milk, it may affect production volume in the mother. Breastmilk takes nutrients from the mother. That is why mothers get cavities during and after breastfeeding more often, because the necessary nutrients are leeched from them to fill the milk. My diet during breastfeeding caused my calories to be decreased by default and I lost 40lbs and successfully fed my son for 21 months.

It is NOT a question of milk quality. It is a question of milk quantity. This varies from woman to woman. She is already producing enough milk for a toddler plus an infant. So long as her QUANITIY of milk doesn't decrease, it is not an issue.

Okay, from a chemical stand point. milk is milk. If it had a different chemical composition it wouldn't be milk. An example is water, water is water, you can add dirt to it(analogy for mercury) it's just water that's dirty, but it's still water.

In theory the milk should be fine, assuming she's not contaminating it. Topics like these kind of bother me. As yous aid yourself, the nutrients come from the mother. She's the one who will be lacking, not so much the baby. But milk production... that is a problem. So yes a diet can have a negative affect, the baby can just starve. I just don't get, why is it so necessary to put herself or her baby at possible risks because she wants to follow a low carb diet? Assuming she has no medical issues, it's just pointless. At this point in time, I don't think she should toy around with this decision.

Without resorting to the vegan and starvation strawmen, what, exactly, are the potential risks of the mother eating a micronutrient sufficient low carb, moderate protein, high fat diet that you're so afraid of? And be more specific than "death." What, exactly, would be in a low carb, high fat diet that would "contaminate" her breastmilk?

Also, if pregnant or breastfeeding women avoided everything she wasn't "100% sure of the effects" with, the human race would die out (or, at best, the economy would collapse). We're constantly exposed to countless numbers of things that have the potential to help or harm the child in ways we can't even yet begin to understand. Can't eat meat, because animal fat and organs hold the toxins they were exposed to. Fruits and vegetables are out, too, because even organic pesticides have unknown effects, and even ones that weren't directly sprayed are exposed to toxins in the air and water. Can't drink water, because there's fluoride, chlorine, and other chemicals in it that have unknown effects. Can't breathe air, because there are loads of toxins and other compounds in the air.

Also -- there are no societies that are vegan. Indigenous populations value the nutrients from animal sources so highly that the ones with the least amount of access to animal sources will go to the greatest lengths to obtain them -- to the point that they will resort to cannibalism if they have to. ( http://www.westonaprice.org/uncategorized/weston-price-looked-for-vegans-but-found-only-cannibals/ ) Even the supposedly vegan "Blue Zone" societies aren't completely vegan (except the Seventh-Day Adventists, who are vegan for religious purposes and still go out of their way to supplement B12), and, in fact, depend on such sources of meat as pork and seafood.

Once again, why even take a chance? Why even risk it if you're not 100% sure of the effects?

It's called "parenthood" - there is no entry exam or mandatory training, you get this life form to care for and do your best.

There are documented cases of successful breast feeding LCHF mothers just as there are of mothers eating the SAD diet. Clinical trials on babies tend to be frowned upon.

"The principal sugar of human milk is lactose but 30 or more oligosaccharides, all containing terminal Gal-(beta 1,4)-Glc and ranging from 3--14 saccharide units per molecule are also present.". Concentration of carbs is ~7% and volume ~800 ml a day so we're looking at ~50 grams/day of lactose which is primarily made from blood glucose when in the fed state.


http://www.peds.umn.edu/prod/groups/med/@pub/@med/@peds/@neonat/documents/content/med_content_249650.ppt
cites "Hexoneogenesis in the human breast during lactation" - Sunehag et al http://www.ncbi.nlm.nih.gov/pubmed/11788663

Yes. It's called parenting.
I take my children's lives into my own hands everytime I strap them in the car. Cars ARE 2 ton killing machines. I sometimes feed them processed foods and expose them to chemicals in the air and from the containers in which their foods are contained. I must be a terrible parent.

The issue is obviously not quality of the milk. It is quanitity. As I have already established. The part of the world in which we live is considered privileged. After all we are discussing something on the internet. Some of us on laptops, tablets, or phones. First world problems. And in this first-world, a child isn't likely to starve from breastfeeding. The OP has already mentioned that she has a good supply of frozen breastmilk. She obviously produces enough to feed a toddler AND an infant. Should her supply decrease AND she runs out of frozen milk, it's a short drive (in the killing machine) to a store to buy formula. The baby won't starve.

Mothers burn approximately 500 more calories daily just producing their milk. This can pose a problem with supply if the mother regularly does not get enough calories, especially when tandem nursing. OP doesn't sound like she is daft enough to not notice if her baby isn't getting enough milk. She even said she would monitor her supply. The baby will clearly demonstrate it is not getting enough by squalling like a siren! The vegan family mentioned probably were a rare exception in which the parents were not doing adequate parenting, the basics of which of course are making sure the child is fed enough. You can't fix crazy. It was a tragedy, but has zero relevance to the discussion. Some people are just bad parents. Quality of food or quantity of food won't change crazy.

We 100% know the effects! Either the mother will go on Atkins and do fine, continuing to produce enough milk to feed both, or will not produce enough and have to either a)stop the diet, b)stop nursing the other child, or c)supplement with formula.
Simple. Starvation isn't in the equation. The mother would have to be crazy enough to starve herself or starve her child without noticing any increase in the child's appetite. Breastfeeding is not only a method of feeding your child. It is a relationship that thrives on cues from both the mother and the infant. Breastfeeding mothers are already in tune with their babies' cues. To not notice changes in the relationship would be a special level of "lost in space." You'd have to be trying very hard NOT to notice. That would then be neglect. That isn't what is going on here.

Risks aren't all equal. Parents have to do cost-benefit analysis pretty darn frequently. Were I to make the decision, I would wait. The child should at least be 6 months old if you wanted to experiment. At that point, supply should be well established. The machine well-oiled and humming along, as it were. Any wobbles in supply could be easily remedied at that point, should it happen.

I think supply establishment is moot in this situation. The odds are very good that the toddler wasn't weaned off then allowed to nurse when the baby was born. Therefore, the supply has been established for several years. One could argue that the increase in supply has changed, but the body adapts to that within a couple of weeks.

I do agree, though, that in the usual *only started breastfeeding with this child" situation, the 6 months is a good guideline.

Without your strawman... (hate to qoute sarah and her alan aragon BS). The premesis has been set already, to answer your question directly, the answer is "malnutrition." Deficiencies for the mother and/or child. No one said "vegan cultures/societies." What was said was, something along the line of "NEAR vegans." Some cultures eat more animal protien sources than others. There is a spectrum, some cultures eat a lot of animal protein, some eat very little. I was talking about the end of the spectrum where the people eat very little.

You're still being deliberately vague.

Be more specific. "Malnutrition" is just as vague your constant yammering about "possible risks" that has so far been nebulous, Chicken Little-esque hand waving.

What, exactly, is a person missing out on going on a LCHF diet? What deficiencies would develop that wouldn't on a SAD/Western diet?

Vitamin A? Eat a little liver.
Magnesium? Dark leafy greens, nuts, and fish.
Folate? Eggs (added bonus, you get choline, too)
Calcium? Boney fish and leafy greens

Breast milk is mostly composed of lactose(milk sugar partially made from glucose(carbs)) and fats. Take note, glucose(carbs) is mostly what the breast milk is made of. Now if someone is on a low carb diet(lacking carbs) and breast feeding what are the effects?

Gluconeogenisis. The body doesn't need hardly any carbs from the diet, because it can create it from protein and fat. Also, like the ketogenic body does with the carbs that are consumed, it will prioritize things like producing milk and fulfilling the brain's need for glucose and will keep the glucose out of muscle and liver glycogen.

This won't cause problems, because the body will give to the baby what it needs, and the mother's body can run on ketones.

I am also sure there are cultures who didn't eat much meat and breast fed their babies, cultures that where more towards vegan. The vegans can use that logic too as you just did. Once again, we know the result.

This is the "vegan societies" thing I referenced. I guess it depends on what you consider "not much meat." As I said, the societies with the least amount of access to animal foods went to the greatest length to get them, even up to and including cannibalism. Additionally, my point is that the societies that are lauded as being "vegan" (or heavily vegetarian) are actually far from it.

For example, the traditional Okinawan diet is not vegetarian, but based around pork and pork fat.

Many of these societies also gave preference to their pregnant women, giving them the best cuts and most nutrient-dense organs from their animal sources.

A mother breast feeding her baby while she is on a low carb diet. What are the effects? Who knows... There is no research that I am aware of on this subject.

While you are sort of right in that you won't find the traditional "let's do this thing to this human subject and see what happens" sort of studies (see also: Little Albert for the details of why that's frowned upon, though that probably should be drilled into your brain), we actually aren't totally in the dark about it.

Dr. Weston Price traveled the world in the early 1900s, studying indigenous populations to see if they had the same rate of cavities and dental issues that he was seeing rampant in his Cleveland, Ohio dental practice. He lived in a unique time, when the indigenous people he studied still had large parts of their population uninfluenced by Western society, and was able to compare the "Westernized" populations with their isolated counterparts. What he found is arguably mind-boggling -- dental and overall health that was unique to humans as a species in its near-perfection. Even more, he found that not only did dental health decay as the people became more Westernized, but other physical and mental markers were markedly deteriorated alongside dental health (ie - the isolated people rarely, if ever, suffered from things like appendicitis or gallbladder issues).

Among the people he studied were the Swiss, Gaelics, Inuit, Maori, American Indians, Australian Aborigines, and 30 different African tribes, including the Maasai.

Of particular interest to this conversation are the diets of the Masai and Inuit, in particular. The Maasai people live almost entirely off of the cows they herd -- meat, milk, and blood. The Inuit (and their Scandinavian counterparts, the Sami people) live almost entirely on land and sea animals, particularly in the winter months. Yet, Dr. Price found these people to be robust and healthy by all accounts. What were pregnant women and young children fed by the Maasai people? They were ensured a daily (or nearly so) ration of blood, and butter was an important infant food.

Simply put, if low carb eating was so detrimental to lactating women, these people wouldn't even exist. Arguably, we wouldn't exist, for that matter, because there were great stretches of time when carbohydates simply weren't available (ie - ice ages).

The two takeaways:

1. We're not as in the dark about the effect of a low carbohydrate diets on pregnant and nursing women as you seem to believe.
2. Your Chicken Littling is entirely unfounded.

Here's a copy of Nutrition and Physical Degeneration, Dr. Price's book on the time he spent with these cultures. I highly recommend reading it -- http://gutenberg.net.au/ebooks02/0200251h.html

<snipped>
This entire nonsense conversation is rooted in "worse-case-scenario," not "without-a-doubt-gonna-happen." If x happens and y happens, maaaaybe there's the off chance that z will rear it's ugly head. But we are talking low probabilities.

<snipped>

"nonsense conversation rooted in worse-case...." is a much more polite description than I'd use.

Not because the topic isn't an important one and worthy of discussion, but rather because the original premise of the debate was:

I meant, why are you willing to risks the baby's health?
<snipped>
There is a story of this vegan family that had a baby. They fed the baby vegan food, it died.

Fear mongering and citing a one-off example as "proof of fact" is about as far as one can possibly get from the scientific method and intelligent, scientific discourse.

Might work for the clown car talk radio jerks - not so much for someone considering a future in the scientific community.

<snipped>
This entire nonsense conversation is rooted in "worse-case-scenario," not "without-a-doubt-gonna-happen." If x happens and y happens, maaaaybe there's the off chance that z will rear it's ugly head. But we are talking low probabilities.

<snipped>

"nonsense conversation rooted in worse-case...." is a much more polite description than I'd use.

Not because the topic isn't an important one and worthy of discussion, but rather because the original premise of the debate was:

I was trying to be nice. It's better for me to be nice than say what I am thinking most of the time. My inner monologue is a bit of a witch.

Yes. The premise is, to me, absurb. But again. I'm a woman who breastfed 4 kids, and the last on a low-carb diet.

Biochemistry helps you understand how the universe works only so much. It's once you get out of the molecules, once you see them correctly,...well, seeing the forest instead of merely the trees is important in its own right.