I'm sure someone can point to a good writeup on this.
I'm a firm believer that this explains a ton with initial success, later failure, and a host of sub questions.
All food we take in has to be digested, absorbed, or eliminated.
This process is largely regulated by gut bacteria. We are amazingly adaptive creatures with amazing guts.
Most diets work short-term , I believe this is due to caloric restriction. Inadvertant restriction. As we change our dietary intake drastically, our guts have to adapt to the new caloric source.
Now before we explode into calories in vs out debate, this is calories in vs calories absorbed, an inadvertent restriction in calories
Those people that eat all they want without gaining weight likely have horrible gut health and poor food absorption
Those of us that look at food and gain are simply efficient
Those of us who lost heavy, and started regaining may have simply healed our gut and adapted.
I say this for people eating static amounts, the obvious solution is to be completely honest with your body and not follow societal eating norms and only eat when and portions as you feel you need for satiety.
I find I eat less now than when I started, yet I'm still packing on muscle... But my eating schedule is now erratic ...
Thoughts? Studies? Writeups?
Edit: to clarify, I'm talking calories absorbed(regardless of partitioning) vs calories eliminated thru waste. A more efficient gut would dump less calories, break them down to be used better.
If you eat 2000cal and you're pooping out 500 cal, presumably your body has 1500 to partition how it pleases.
If you eat 2k cal of different food your gut isn't used to and you poop out 1000cal, you're at a 500 defecit from before( we will presume no other hormonal or macro changes)
As you continue eating adaptive diet, your gut "learns" how to extract these new calories and defecit ends.
Gut bacteria and enzyme adaptation barring thermal and hormonal changes, I think play a great role in weight.
I'm looking for info on calorie absorption for those eat 7000calories don't exercise but don't gain weight people. Food in vs waste out, gut biopsy etc.
The fecal transplant tests seem to coincide with my theory as well as changing out te bacteria changes absorption and near immediately affects weight. Mind you I don't think bacteria are the sole reasoning, we are far too complex hormonally for that. But I think they are major major players.
To me this makes logical sense why all diets work at first then ultimately fail, and why quality bacterial change an hormonal change is the only long term solution( paleo does both)
Nephropal just did a great writeup: http://nephropal.blogspot.com/2011/01/intestinal-flora-and-obesity.html
Some things to think about, since this is an interesting but simplistic theory:
Gut flora is a lot more complicated than merely determining caloric absorption - a good resource for scientific information as well as n=1 experimentation (with the Eades' 6-Week Cure) is Dr. Ayers' Cooling Inflammation. Destabilising gut flora can have significant impact on metabolism and fat set-points, beyond just whether or not you are accidentally restricting calorie absorption.
From the same blog:
"Gut Flora Is Diverse and Adaptable Gut flora appears to be amazingly diverse from individual to individual with thousands of bacterial species inhabiting humans worldwide and about 150 species in each individual. The same species remain in an individual for long periods of time regardless of diet. The dominance of particular species depends on recent diet. Major changes can result from antibiotics or gut diseases, e.g. Crohn’s."
And Dr. Ayers' own experience with messing with gut flora balance through diet changes:
"Bad Habits and Portion Control Alas, I had forgotten that the main reason for going on this gut transition diet, was to destabilize my gut flora, so that I could more easily change my metabolic set point to lose some visceral fat. I apparently succeeded, because after a couple of days my weight had very easily increased again. I was clearly taking in too many calories and there was little resistance to weight loss or gain."
The whole blog makes for some very interesting reading. I'm still making my way through it.
The only thing I would add is those that gain easy may still not be 'efficient.' It has been shown that your organs and vital systems can be starving even as you are gaining fat. This hormonal problem, an example of which is seen with hypothyroidism, is a problem of storage and the calories being stored at fat instead of going where they are needed. So in fact, it is not efficiency but inefficiency that is the problem in such situations.
On the flip side, skinnier people may be absorbing well but the calories may be going towards things like a high energy lifestyle. An athlete is a good example. Athletes must eat a lot in order to fuel their exercise habits. But there are regular people who are simply very active in life who may need to eat more or perhaps they eat more and this is channeled to fuel a high energy lifestyle (hard to sort cause and effect sometimes). So while I don't disagree that absorption effiency is probably also a factor, I also think there are probably many other factors that make it complicated.
I think what you are looking for is info on calorie partitioning (aka nutrient partitioning), and there are a plethora of factors that influence how "efficiently" calories are utilized: genetics, training, meal timing and macro composition, etc.
Lyle McDonald writes about this subject quite often:
If you have some time to kill, here's a really interesting BBC documentary on why skinny people tend to remain skinny:
Well, i wonder if this adds any to the conversation (good question, btw): I feed my 1.5 year old pitbull only raw meaty bones. Think things like rib-in chicken breast, etc. He has been all raw since 3 months of age. Rawfed dogs' poops are way way different than "normal" dogs. Even healthy dogs that eat some of the newer grain-free canned food, even their poops. Vegetables and other fillers in there bulk up the stool that most people are used to dealing with. So those big, well-shaped logs of easy-to-pickup poop are a product of in fact poor nutrition. Low absorption by the dog's body and thus high excretion.
Now, look at a rawfed dog's poop: it varies! It depends on the prior meal. However my point is that it is almost always smaller than a cannedfoodfed dog. I would posit that the dogs are simply absorbing more of the meat and fat, so there is naturally less to excrete.
Our body stores excess food energy as fat. Many of us eat a lot without doing a lot of physical activity. It doesn't make sense that our body would let that go to waste. When we lose fat, our bodies are using those fat stores as energy. One pound of fat has 3,500 calories of energy in it. A calorie deficit of 500 a day will cause a weight loss of one pound a week.
When someone loses a lot of weight and then gains a lot of it back, it's not because they develop efficient absorption of calories. It's because they "fall off the wagon" and return to their old habits. They think "I'm thin now, so it's OK". And then over time, they gain.
Yeah, it sounds like calories in, calories out. I refuse to throw that out the window in favor of whatever Taubes says (don't exercise, eat whatever amount of calories you want as long as it's low carb).
Insulin is not the big bad wolf. Insulin is very important in the body. When one loses the ability to maintain normal insulin levels, that person has diabetes. In Type 1 diabetes, they have to take insulin injections to stay alive.
Head aches, second month of Paleo. 0 Answers