Do you have any more information on this "mild toxicity"? That does not sound like a healthy reaction to me.
My understanding was health experts encourage insoluble fiber more than anything, precisely because it is essentially inert — not digestable or fermented by microflora — and therefore merely adds bulk to the waste, which helps move stuff through the gut. Are you talking about soluble fiber and prebiotics?
This isn't an accurate portrayal of the benefits of fiber. The laxative effects of fiber are just one of many benefits. For example, Fiber can bind to saturated fats, disabling the negative affects of them. Specifically, in terms of bacteria, many bacteria digest fiber, which in turn creates short chain fatty acids, which have many health benefits.
You're right about one thing, though: this is indeed a complex subject.
Very interesting.
Can you maybe refer to some text(s) about this phenomenon of mild toxicity from digestion of fibers?
About 10 years ago I switched overnight from a very meat heavy diet to mostly plant based (I still eat dairy products and one or two servings of fish per week).
Within a week I was shocked at how well my digestive tract was suddenly working. Before that I had no idea how broken it was.
All other factors aside, I could never go back to the slow, uncomfortable digesting process of a typical USA meat heavy diet.
Everyone is different.
Granted, I can't entirely separate the effects of ketosis in and of itself from an overall cleaner diet with more vegetables and fewer processed foods. It's possible that the same diet with butter swapped out for quinoa would have yielded a similar result.
As far as sweeteners, my go-to is liquid stevia, which I use about 1/5 a cup of daily. When I need a solid sweetener (e.g. for baking), I use inulin fiber sweetened with stevia and monk fruit, which creates a nicer texture than actual sugar IMO. I also have allulose on hand for specific use cases (e.g. caramelizing), but I can't really stomach it in large quantities.
The added benefit is that my diet is much higher in protein and lower in carbs, which definitely has helped me build and maintain muscle and reduce dad bod.
Again, just annecdata, but maybe individuals have differing nutritional profiles that work best for them?
The goal is to keep your microbiota as far as possible to a monoculture.
I am absolutely not an expert on this subject, but so far, my understanding is that there are not really "healthy" bacteria, there are only healthy mixes where different species balances and keep the other from growing.
Citation?
https://www.nhs.uk/conditions/lactose-intolerance/causes/
"Bacteria in the colon break down the lactose, producing fatty acids and gases like carbon dioxide, hydrogen and methane.
The breakdown of the lactose in the colon, and the resulting acids and gases that are produced, cause the symptoms of lactose intolerance, such as flatulence and bloating."
In practice, your reaction to lactose is difficult to predict, regardless of your production of lactase.
When you ingest something that you can't digest directly, there is a good chance that some bacteria in your guy can. And when they do, they multiply, this process is often faster than most people realize.
The problem rarely are the bacteria themselves, but the byproducts of their own metabolism, that can be benign is trace quantities and harmful in larger quantities.
The immune system also constantly monitors and reacts to those byproducts and bacteria population.
What we usually call Lactose intolerance or Gluten sensitivity is in practice an indirect effect of some species of bacteria digesting those, and then the reaction of your immune system.
Overall, the gut microbiome is a fascinating and complex subject, unfortunately often oversimplified or misunderstood.
As an example, we've often been told to eat more fibers to increase "flow", the flow increase is because the fibers are digested by bacteria and the mild toxicity of the process forces the digestive system to flush everything.
Same with Sorbitol (contained in dried prunes and often used as a soft laxative) but even more toxic.