There is discussion about how low carb to normalize weight works for some and not for others. Questions of why obesity increased with the modern diet while macronutrient ratios appear not to be causative when compared to minorities and the past. Certainly there must be a causative factor that came to dominate the standard western diet.
Fructose availability and consumption have increased dramatically. At least 1/3 of westerners have fructose malabsorption, most of them asymptomatic on the surface.
There are various types of gut flora and there is a type of gut flora that can make people obese (PMID 17183309 et seq.).
Unabsorbed fructose ferments and feeds bacteria in the gut. Starch can also be malabsorbed. Metabolites of these bacteria can cause inflammation and autoimmunity. Can they cause obesity too?
Some people do not tolerate carbs ??? why, if not because of gut flora? IBS and IBD have been on the rise for a while. They respond to carbohydrate and FODMAP reduction. The SCD and GAPS diet do not always work. I think they have serious limitations because they allow honey, fruit, fermented dairy and other FODMAPs. It makes no sense to allow honey and fruit on these diets but not dextrose when many people don't absorb fructose but would absorb glucose.
If somebody goes on a low carb diet, they greatly reduce the potential of fermentable carbs. If an individual goes on a low carb diet and still eats some fructose or FODMAPs, it may or may not be enough to shift gut flora sufficiently towards fewer Firmicutes and more Bacteroidetes so as to enable proper leptin metabolism.
asked byDean (1520)
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on August 12, 2011
at 12:35 PM
Growing up, my sister and I ate the same things pretty much. We ate a lot of junk food. I was always thin, even underweight. She was overweight. I had chronic stomach problems and autoimmune issues, she didn't. When the doctor put me on drugs for my stomach problems was when I started to gain weight. I think carbohydrate intolerance makes you less likely to gain weight since your gut will be too irritated to absorb as much. In my experience, people who are fructose or FODMAP intolerant tend towards the leaner, but I didn't have any studies on that.
Most of the articles I've read on obesity and gut flora says that the obese have more efficient gut flora and may be extracting more energy from fatty acids and carbohydrates than the bacteria of a lean person. They also might not be as good at signaling satiety.
A low-carb diet will reduce the amount of most bacteria, which could help if the person has those super-efficient bacteria. But in general this also might explain why so many who lose weight on low-carb gain it all back with absurdly small additions of carbs into their diet- the problem was never fixed. What needs to be fixed is the diversity of bacteria, which promotes a proper balance. Unfortunately, this diversity is often established at a young age and can be ruined by antibiotic use.
What might be negative is that it reduces the amount of SCFA-producing bacteria, which modulate inflammation and the appetite. To mitigate this, some low-carbers take inulin, which has shown promise in some studies, or exogenous SCFA such as butter (butyrate).
on August 12, 2011
at 04:37 PM
That's an interesting supposition. When I started doing Paleo, I noticed that starches would give me serious indigestion in the form of gas, bloating and grumbling. White rice, potatoes, etc. And even though I was getting plenty of fiber from greens, fruits and veg, constipation was a serious problem that was making my life miserable. Taking MiraLax once a day just so I could do a poo that didn't tear my butthole apart was getting old, fast.
Then I got a lovely case of food poisoning from left over chicken salad that pretty much wiped my gut clean of any bacteria, good or bad. After the vomiting and butt water phase subsided, I was still pooping basically water, and several times a day--anything I ate was moving through my system too quickly to be absorbed properly. I began taking a basic probiotic--
--and within a couple of days my poops were back to normal, and have been ever since. No more constipation either, and this happened back in mid-April. I can now digest starchy foods with no issues whatsoever, it's awesome! I still take a probiotic with dinner each night, but if I skip a day or two it doesn't have a noticeable effect on the outcome in the morning ;)
I definitely think that having the wrong strains of gut bacteria can lead to digestion problems.
on August 12, 2011
at 03:53 PM
That's a very interesting idea. It could be the reason I can tolerate almost no carbohydrate whatsoever. I have basically 3 conjectures, and bacterial or otherwise microorganismic involvement, is one of them, be it in the gut or elsewhere. The others are (1) intolerance to specific compounds like anti-nutrients / toxins in vegetables, or (2) needing to be in deeper ketosis, just like some epileptics will respond only when ketosis is deep enough. My problems were psychiatric, not just bariatric, so it's more obviously about the brain, although weight problems are of course also brain problems.
on August 12, 2011
at 01:33 PM
*A low-carb diet will reduce the amount of most bacteria, which could help if the person has those super-efficient bacteria. But in general this also might explain why so many who lose weight on low-carb gain it all back with absurdly small additions of carbs into their diet- the problem was never fixed *
I think that's where GAPS might be beneficial. Most GAPSers turn WP when done with GAPS,so they eat some amount of carbs&fructose,even grains. Yet they aren't obese,so I guess that might be bc they restored their bodies/metabolisms on GAPS?