Lately I've been noticing the stirrings of a Paleo backlash in the fitness/nutrition community. Not that the backlash is just starting - I have no idea, to be honest, how entrenched it is - but I can guarantee that it's going to get a lot worse. As more and more people use some version of the Paleo diet to look, feel, and perform better, more and more public authorities on nutrition (doctors on TV, nutritionists, journalists) are going to write articles and give talks about how misguided it is. You will read these articles, your friends will read them, and your family members will read them. You may or may not be swayed by some of the things these Paleo-haters will write, but I guarantee members of your family and circle of friends will start to think that you're killing yourself by eating the way you evolved to eat and avoiding modern innovations like "heart healthy whole grains" and the statins that come with them.
The Paleo-haters will use a number of tactics in their arguments. They'll argue that you can't poop without fiber (because if you eat a grain based diet and are sufficiently mineral deficient you can't, and they can't imagine what it feels like to NOT be mineral deficient). They'll simply lie and say that dietary saturated fat is harmful to your cardiovascular system. They'll say a lot of things. One of the most common tactics I've seen (and I can guarantee you'll see more of) is the straw man argument. Now it's time for a little logic lesson (in another life I actually taught classes in logic, so I'm licensed to discuss this in public).
The basic format of a straw man argument is that you attach a weak claim or position to your opponent, then tear that weak claim apart, then claim victory over your opponent. We see this in politics all the time - some candidate is pro-choice, for example, and his enemies will make campain ads that say "Candidate X hates babies and wants all life to end." Well, that's not exactly his position, but since baby hating is so horrid and indefensible, the candidate is lessened in the eyes of the voters. You'll see, "Paleo authority Y thinks we should live like cavemen and stop wearing clothes," when in fact that authority wants us to eat our natural diet and has nothing against clothes (shoes might be another story...).
Here's a short list of the things you're going to be hearing and seeing if you start a paleo diet (some of which are straw man arguments, some of which are not):
So you're living like a caveman now? You won't immunize your kids or go to the hospital if your appendix bursts? This is classic straw man at work. While I'm sure some Paleo diet proponents are against vaccinations, that's not the position of the majority of them. The Paleo diet just means that we're susupicious of foods that haven't been a big part of our evolutionary history, not that we eschew all modern conveniences or innovations with a proven track record (like trauma medicine and polio vaccinations).
How can you follow that diet when we don't even know what paleolithic people ate? This is sort of true but both misguided and irrelevent. We don't know exactly what paleolithic people ate - I'm sure the diet varied from place to place and over time with changing climatic conditions. Even accounting for that, it's hard to be certain about the exact ratios - did they eat entire animals or did they eat the fatty parts first (as I suspect)? How much of different types of vegetation did they eat? The thing is that this argument misses the central point of Paleo eating. We may not know exactly what they did eat, but we know for certain many things that they didn't eat. No grains, for example (the technology to process grains and cook them is relatively recent). No nightshades (they're Western Hemisphere plants, they didn't exist in the places where the bulk of our evolution took place). No refined sugar, high fructose corn syrup, artificial sweeteners (this should be obvious). So to be suspicious of those foods does NOT require us to absolutely know exactly how paleolithic peoples ate.
The primates that are our closest animal relatives are vegan, so we are obviously "meant" to be vegan as well. This one you'll hear a lot from... vegans. I'm not going to get into a huge debate about how many bugs or other animals chimps or apes eat - they do, but I don't care. Here's a newsflash for you: you are not a chimp (unless you are, in fact, a chimp, in which case I apologize, and kudos for learning to read!). Chimps are related to us but have followed a distinctly divergent evolutionary path. They have much larger guts than we do (room for lots of bacteria to process leaves and plants into usable nutrients), smaller brains relative to bodyweight (reducing the need for essential fatty acids), and can spend all day (or most of the day) chowing down on plants, which are not nutrient dense, to get the food they need. Humans evolved thanks to eating meat - only the nutrient density of meat allowed our ancestors to support theirr energy-hungry and fat-hungry brains (try to develop a human brain with flax oil - not gonna happen). It was meat eating that allowed us to become human. Apes can eat leaves and twigs all day, and bacteria in their guts turn those into fats their bodies can use for energy. Our guts are too short for this to work. If we want that energy, we have to eat butter... or something. If you had the gut of a chimp you could thrive as a vegan. Otherwise, watch out.
You're using the term "Paleolithic" incorrectly - that term refers to the period from X years ago to... blah, blah blah. Answer: Who cares? Seriously. I'm not an anthropologist. I have no idea what the word "paleo" really means in terms of actual years - I have spent exactly 0 hours looking into that issue. The point isn't the correct use of the word - the point is that there was a lifestyle and eating pattern that distinguished our evolutionary ancestors from other primates, that allowed us to evolve, and it's pretty obvious that after a few million years we'd be well adapted to that eating pattern, and it focused on eating whatever animals we could hunt or scavenge and whatever vegetables we could find by foraging. If we're calling it by the wrong name, so be it. Let the academics worry about it. Who cares if the eating style that makes us feel better and be healthier is mislabeled?
But Paleolithic humans only lived to be 35. I think I've addressed this before. It's simply wrong, and it's based on listening to people who don't understand basic math. Paleolithic era humans (and primitive hunter gatherers through today) may have had an average lifespan that was much lower than ours, but that's because their child mortality rate was much higher than ours and their trauma medicine was much worse. A badly broken leg in primitive conditions is often a death sentence - today, not so much. So if three kids are born to hunter gatherers and one dies in infancy, one is murdered or gets mauled by a bear and dies at 40, and one dies in his sleep at 80, the average lifespan will be 40. Can we infer from that number that their diet causes heart disease? Absolutely not. Lots of studies of both paleolithic remains and contemporary hunter gatherers living without modern medicine show that those people are almost free of the diseases of aging (heart disease, diabetes, arthritis) that plague modern man and that they live a nice long time barring injury, infection, or violence.
We didn't evolve - God slapped us down here just over 5,000 years ago, and He (or She) planted a fossil record and put vestigial limbs in animals and created a detailed mitochondrial DNA trail to falsify evolution to test our faith. If someone pulls this one out on you, don't argue. Pick up your drink and walk away. There is nothing you can say or do that will help in any way whatsoever. The ship of reason has sailed. If someone is willing to rationalize away the quantity and quality of evidence supporting evolution then no possible evidence in favor of any diet will convince them.
You're just jumping on the latest bandwagon. Well, okay, that's fair. But the paleo diet is like Naruto - it's popular because it's good. I know it's cooler to be into things that are fringe or counter to convention, and it's sad in that sense that Paleo is getting more and more mainstream, but that in itself is not a reason to think it's bad. It just means that us Paleo eaters aren't as cool as we'd like to be.
But I need to eat every 2.5 hours or I pass out. Let's say this is true. Do you think that's your natural state of being or is it the result of you having trained yourself to consume food 6 times a day? Do you really think that our hunter-gatherer ancestors would fall unconscious to the ground every time they spent 3 hours without food (say, during a bad hunting day)? Without getting all National Geographic on you, do you really think we'd still be around as a species if that happened? Try going without food for a few hours at a time until you've built up the ability to burn bodyfat for fuel. Then you too can go 20 hours without food without skipping a beat - that's what I do!
I need carbs to function at the highest level. Maybe, maybe not. But regardless, this is another straw man - the Paleo diet is not necessarily low carb. I personally eat a moderate carb diet - it's Paleo because the carbs come from fruits, veggies, and root veggies, not grains. Most people who think they need to eat a lot of carbohydrate would be fine if they ate a low carb diet for a few weeks anyway.
We've clearly had enough time to adapt to neolithic foods - it's been 10,000 years! This one is, to me, a little tricky. Populations that ate dairy for 1,500 years did lose lactose intolerance - which is not to say that even those people don't suffer leaky gut syndrome from consuming dairy. Maybe the prevalence of coeliac disease in the general population is a clue that this is wrong. Maybe the fact that so many of us feel so much better, and get so much healthier, when we give up grains is the clue. And maybe some people are adapted to a grain diet (though I doubt it) - how would one know? The answer has to be to try Paleo eating for 30 days and see how you do. If you feel better and are healthier, then none of the arguments that anybody brings up should hold any water with you.
Why do so many "experts" rail against the Paleo diet? Well, think about it. Suppose your name is Leigh and you're a fat loss "expert" or trainer or nutrtionist or whatever. You have to either jump on the Paleo bandwagon yourself - and explain how you never realized before how much damage grains, legumes, and dairy do to your clients despite the abundance of research that's been published on the topic - or you have to rant against it. Very few people have the intellectual integrity to recognize that they've been wrong, especially about some field that they supposedly know a lot about, and change their tune. Plus, there's a financial issue. Paleo is pretty simple to implement and doesn't depend on a whole lot of supplements or special powders. If you plan to make a living doling out nutritional advice you don't want your clients reading Robb Wolf - they're not going to write you a check afterwards, they're going to follow his advice and get great results without you.
I'm sure you'll see more specious arguments against Paleo eating as time goes on. When the munchkins try to bring you down you have two general choices. You can study a ton of evolutionary biology and anthropology so you can answer their charges one by one. OR you can use the 30 day test - just say, "hey, maybe you're right, but I tried it for 30 days and I feel better/ healthier - have you tried it?" every time someone challenges you. Or just lift your shirt and show them your cheese grater abs. Either way, don't let them derail you from your path to health.