Can The Paleo Diet Can Be Bad For You?
What very popular diet
is loved by a high percentage of health-minded people and yet has relatively few studies
to its credit? Yes, I'm talking
about the Paleo Diet. The Paleo, or Caveman Diet as it is sometimes
called, has taken the U.S. by storm in the last 5-10 years. From what I've
seen, it is by far the most popular diet among health-minded American men right now.
(Some men also eat a related diet, call "Primal".)
Of course, I don't think many people disagree with the concept of trying to eat "Paleo," if by that one means trying to eat according to our evolutionary and
developmental ancestry. In fact, I consider myself "Low Fat Paleo," something you can read about here if you are interested:
Low Fat Paleo.
And there is a study out there that shows the significant potential of a Paleo Diet on healthy individuals. Check out these impressive results achieved by a Paleo Diet:
--"Total Cholesterol went down by 16%.
--LDL Cholesterol went down by 22%.
--Triglycerides went down by 35%.
--Insulin AUC went down by 39%.
--Diastolic Blood Pressure went down by 3.4 mmHg" 
And here is what was REALLY impressive: the study made sure that no one lost weight. Almost any diet will produce impressive results if the participants are losing weight. So the Paleo Diet achieved some nice results.
So this is an open and shut case then, right? Well, you have to keep in mind something important: the study was composed of only 9 individuals.  Also, notice that the authors stated that "we compared the findings when the participants consumed their usual diet with those when they consumed a paleolithic type diet. The participants consumed their usual diet for 3 days, three ramp-up diets of increasing potassium and fiber for 7 days, then a paleolithic type diet comprising lean meat, fruits, vegetables and nuts, and excluding nonpaleolithic type foods, such as cereal grains, dairy or legumes, for 10 days." 
Clearly, this was a very small sample and the directions as to how to do Paleo were rather broad and open to quite a bit of interpretation. Again, all of the above is a good sign but certainly nothing definitive in my opinion. NOTE: All the other Paleo studies that I know of had the study participants losing significant weight which makes them relatively useless in comparing with other diets.
So let me jump right to the point: I think that sometimes the modern, American implementation of a Paleo Diet will likely get many men in trouble, and below I want to mention some of the things that a lot of guys simply don't think about it:
1. A Demphasis on Arterial Plaque. I have personally never met anyone on
Peak Testosterone Forum that
eats Paleo that has much of an interest in atherosclerosis. Common numbers that I see are high LDL-C and HDL coupled with low triglcyerides. What this could mean - and I emphasize could - is that they have high LDL-P and apoB. LDL-P (and apoB) are the most important heart disease markers that we currently have and so, if a man is consuming Paleo, and has high LDL-P, it is unlikely that he will be magically protected from developing arterial plaque. (And arterial plaque is hard on erections, since it goes hand-in-hand with stiffened arteries and decrease nitric oxide.)
Now I am not saying that all men consuming Paleo have high LDL-P. But I am saying that they should get it measured just like everyone else should, and I have sensed a resistance there. The reason for this, at least in my opinion, is that so many Paleo gurus hammer at the idea that "cholesterol is good" and "cholesterol is irrelevant to heart disease" and "cholesterol levels have nothing to do with heart disease." Unfortunately, there is a little more to the story: high LDL-C sometimes goes hand in hand with high LDL-P. Not always, but sometimes. And guess what? You don't know if you have high LDL-P unless you test - pure and simple. (ApoB is another good marker.) So get tested if you are Paleo and don't just assume all is well. It may be. It may not be.
2. Overly Ketogenic. Another potential issue with the American version of a Paleo Diet is that it ends up being Low Carb. Basically, it is meat + vegetables and ignores the fruit and "low fat meats" of the above successful study. Once your carbohydrates go low enough, you essentially are consuming almost all fat and protein and are eating a Ketogenic Diet.
Now some men do very well on a Ketogenic Diet, but a big block do not. Study after study has been coming out in the last about ten years documenting some potentially major issues with Ketogenic Diets, including arrythmias, decrease heart function, etc. This is too big of a subject to go into here, but see my
Index Pages for Low Carb if you are interested. If you started out enjoying Paleo for a few months but have been steadily feeling worse, this is a common complaint of those adopting Ketogenic Diets.
3. Affordability ==> Factory Farm Meats. The American version of Paleo has a heavy emphasis on meat generally speaking. Of course, this is largely a cultural phenomenon: Americans eat meat and lots of it and it has been that way for decades now. Growing up, we had meat at virtually every dinner and lunch and a lot of it. This is unheard of in most of the world where meat is more of a luxury and more something that you use to flavor food. American Paleo love the romanticized idea of the "noble hunter-gatherer" for example.
In any event, the American overemphasis of meat leads to a big problem for many Paleo men. Paleo gurus emphasize that one should eat range fed meat, because, after all, that is what Paleo men ate. But who can afford it? Sure, a small percentage of men can afford to eat a lot of range fed meat that they buy from Sprouts or Whole Foods, but most men will end up buying Factory Farm meat. In my opinion, this is incredibly ugly for many, many reasons. Here are just some of the reasons:
a) Almost All Meats: High in injected hormones
a) Chicken, Turkey, Eggs and Farm Raised Fish: High in arachidonic acid and omega-6's
a) Chicken, Turkey, Eggs: Often high in arsenic
a) Beef and Pork: Artificially high in saturated fat
How is this natural and good for one's long term health? And, just as important, how is it Paleo in any sense of the word?
4. Blood Flow. What's the one thing you need for good
erections? Blood flow. Well, actually there are many things you need for a
good erection, but blood flow has got to be right at the top of the list.
Paleo Diet improves blood flow, right? Unfortunately, a Paleo Diet, if implemented wrong, could easily lead to less blood flow. For example, one study pitted a Low
Fat Diet against a Low Carb Diet and found that the Atkins Diet resulted in much
less blood flow.  This was under weight loss conditions and many health
parameters improve when you lose weight regardless as to which diet is chosen,
so this was particularly ugly. Now it is true that a Paleo Diet is not
really a Low Carb Diet in the traditional sense. However, it definitely
is low medium carbs and the Paleo leaders should warn their followers that this
could be an issue if carbs drop too low.
Another study found compared three diets (Low Fat, South Beach and Low Carb) and found that the Low Carb Diet resulted in decreased "endothelial vasoreactivity".  This
basically means that the arteries could not expand or dilate as easily, which
will usually mean less blood flow and very likely worse erections than with the other diets.. The
authors also noted that “the high fat Atkins diet is associated with increased
LDL-C, reduced endothelial vasoreactivity and increased expression of biomarkers
of atherothrombosis.” This is ugly in my opinion.
Now Paleo folks will object, "Well, Paleo is not Atkins (Low Carb)!"
That's true. However, the study also stated that "BART testing revealed a significant inverse correlation between flow-mediated vasodilation and intake of total fat, saturated fat and monounsaturated fat."  Flow-mediated vasodilation is essentially another way of saying blood flow. In other words, the more fat, saturated fat and monounsaturated fats, the less the blood flow!
Most of you will recognize that these are the fats that all the Paleo and Low Carb gurus emphasized. They LOVE saturated and monounsaturated fats and yet these are the fats that will lower blood flow to the penis. Now young men will scarcely notice the difference, because they have so much buffer in their system. But on the forum I have found that middle-aged and senior men simply cannot consume all this fat: they instinctively know that they will often pay the price later.
Again, the study's emphasis above on LEAN meats was well-founded. After all, wild game is almost always low fat. Paleo leaders love to criticize low fat diets. However, this is ironic because most wild game is 10-15% fat and is very low fat. There were no butters or oils "back in the day."
CONCLUSION: In my opinion Paleo can achieve solid results for many men. But it is critical that they test lipid markers and follow the guidelines of the study with the nine particpants.
2) Circulation, 2007, 116:II_819, "Abstract 3610: Comparative Effects of 3
Popular Diets on Lipids, Endothelial Function and Biomarkers of Atherothrombosis
in the Absence of Weight Loss"
3) "Vascular effects of a low-carbohydrate high-protein diet", Proceedings of the
National Academy of Science, Published online 25 August 2009, Foo S, Heller ER,
W20) Prevention, Apr 2010, p. 45.
69) The Journal of Clinical Endocrinology & Metabolism November 1, 2007 vol. 92
no. 11 4480-4484, "Dietary Macronutrient Content Alters Cortisol Metabolism
Independently of Body Weight Changes in Obese Men"
9) Eur J Clin Nutr, 2009, Aug;63(8):947-55, "Metabolic and physiologic improvements from consuming a paleolithic, hunter-gatherer type diet"