Repeat after me... "Correlation does not equal causation."

Chris Kresser recently wrote a good article on fiber. In it he noted, "The majority of the research supporting the benefits of dietary fiber come from epidemiological studies that link the consumption of fiber-rich fruits and vegetables with a lowered risk of certain diseases such as obesity, heart disease and cancer, particularly colon cancer. Yet when tested in the lab, controlled intervention trials that simply add fiber supplements to an otherwise consistent diet have not shown these protective effects." (see http://chriskresser.com/myths-and-truths-about-fiber).

Also, I just found this write up by Mark Sisson where he addressed this very study: http://www.marksdailyapple.com/will-eating-whole-grain-fiber-help-you-live-longer/#axzz21Bauajz5 Long story short, there are numerous cofounders that make it difficult to support the conclusions being asserted.

Give it a read!

That's fine. Why don't you try both diets. Try paleo for 30 days, then try whatever else you think "debunks" it for 90 days and see on which you feel, perform, and look better on.

Make sure it's a fair experiment, measure and test properly. For example, every day log how long you can hold your breath while running at full speed, or how much weight you can lift, etc.

Test your A1C levels, your glucose levels, your cortisol levels, your CRP levels after each diet.

Check your digestion - the shape, size, and frequency of your poops will tell you how well it works. Do you have flatulence - if so, that's a sign of bad digestion, i.e. you're eating indigestible sugars/fiber which are feeding bacteria and causing distress.

By the way "grain intake has been negligible" doesn't work. Either you stay off them 100% of the time, or you don't. Your gut needs time to heal and to stop being permeable. This part is non-negotiable. If you haven't eliminated grains, legumes, (and optionally dairy) for the full period, you're not actually doing paleo - so you won't see any benefits.

http://www.staffanlindeberg.com/DiabetesStudy.html

paleo with lean meats and fruits vs mediterarean

Fiber is an indigestible carbohydrate. It is commonly referred to as cellulose.

Fiber doesn't provide any vitamins, minerals, or nutrients of any kind.

The cell walls of plants are formed of cellulose (fiber). Wood is cellulose (fiber). BTW, where do you think fiber additive companies get their raw materials? Metamucil lists "wood cellulose" as one of its ingredients, which is a nice way to say "finely ground sawdust obtained from lumber mills."

Fiber is fiber. The fiber obtained from wheat is not superior (or inferior) to fiber obtained from sawdust, grass, apples, or any other plant.

2 slices whole wheat bread = 4g fiber, 140 calories

1 apple = 5g fiber, 120 calories

1 orange = 4g fiber, 70 calories

1 cup broccoli = 2g fiber, 31 calories

1 cup carrots = 4g fiber, 50 calories

1/2 cup avocado = 5g fiber, 120 calories

1 pear = 7g fiber, 133 calories

1/2 cup artichoke = 7g fiber, 45 calories

1/2 cup raspberries = 4g fiber, 32 calories

And the list of non-grain sources of fiber could go on and on and on...

By any measure the fruits and veggies listed above are better dietary choices. They contain more fiber, more vitamins, more minerals, and fewer calories than whole wheat.

No doubt confounded right up the wazoo. Epidemiological clap trap.

Here's a balancing source for you:

http://www.gutsense.org/

Konstantin Monastyrsky definitely has the last word on poop. His bottom ('scuse the pun!) line is that ALL fibre is detrimental. Of course, some needs to be tolerated, but don't think you need fibre for "stool building" (man, I'm enjoying myself!) - our "motions" are nearly all bacteria and water (or should be).

I can be found on this site talking about the Inuit a little too often, but hey - no fibre, and no constipation either... oh, and no cancer etc etc (on the traditional diet)

Fiber is good for you, yes, but it's the other crap that's in grains that makes it bad. Your decisions should be based on multiple studies and the result of numerous sources, not just one study. I've always been open to the idea of paleo not being the "right" answer (there probably isn't just one), but all signs so far have pointed me in that direction. And you should also let the results speak for themselves- not just 3 weeks. Any detox and trial on your health should be extensive if you really want to see results. I'm still going through mine, but so far it's enough to convince me that one study won't isn't enough to derail my thoughts.

This is in reply to the "Correlation does not equal causation" post, but I ran out of space. :-)

That post was not only right, it's key. Men who have beards die earlier than men who don't. Does that mean men who want to live longer should shave?? Of course not: it's the kind of man who shaves who happens to live (on average) a shorter life than the kind of man who doesn't. Women who took hormone replacement in the 80's had lower heart attack rates, therefore hormone replacement is good for the heart? That's what was thought until the 90's when they did some controlled experiments and found it caused heart problems. How's that possible?? Again, "Correlation is not causation." Of course, in the 80's, they thought they were controlling for smoking, etc, and they were, but they couldn't control for everything, and the kind of woman who took hormone replacement therapy in the 80's was also the kind of woman who otherwise took care of herself. The hormone replacement therapy was a marker.

So even if this study were not flawed, you couldn't conclude that grain fiber promotes longevity. In fact, given the authorities have been promoting fiber, the situation is parallel to the hormone replacement scenario: the kind of person who eats more fiber is the kind of person who otherwise takes better care of themselves, and you can't control for that well, if history is any guide.

Thanks, Todd B., the reference to the article addressing the fiber/grains study answered the doubts.