Many of my friends and acquaintances fall into the "non-conventional diet" bucket (by "diet" I mean way of eating, not necessarily a weight loss diet). I'm generally OK with that. I don't see much evidence for most of it, but mostly I don't worry about what other people eat or don't eat. I myself have tread down the non-conventional path a few times.
In my little group of acquaintances:
- Many who only do all-organic.
- Many who avoid all artificial ingredients.
- Several vegetarians.
- A vegetarian who also avoids dairy (but not eggs).
- Various levels and styles of paleo.
- Several who eat only traditionally grown and prepared foods (some overlap with paleo).
- A few low-carbers.
- A few juicers and purgers.
- Several who maintain wheat-free and gluten-free (not celiac).
- Several who avoid other particular foods or food combinations.
As I said, to each his/her own: I don't judge. I've been there myself. I was a vegetarian (leaning vegan) for a several years and occasionally get a weird food idea stuck in my head until I eventually stop worrying about it.
People choose these diets for various reasons, including weight-loss/maintenance, general health, or treatment for a specific problem. My main issue with all of them is that there is little or no real evidence that any of them do what they claim. That's not what the promoters claim, of course. Websites and books offer plenty of testimonials, arguments and theoretical explanations with sciency words to shore up their case. Some might even point to a small published study or two.
But… none of that counts as real evidence when dealing with human health and diet. Testimonials or "Works for me!" articles are simply not science. They are someone's unblinded uncontrolled single-data-point test. Arguments and explanations are great, but don't really offer anything in the way of evidence: I can find equally plausible arguments for and against almost any dietary idea out there, each with huge steaming piles of sciency-sounding words and detailed explanations at the cell level. The same goes for small studies. If you want a study showing just about anything, there'll inevitable be one or two that show exactly that, but there will also be one or two that show the exact opposite.
After all these years of watching, reading, and hearing about fad nutrition ideas, I've come to trust only those diet ideas that have evidence in the form of very large epidemiological studies. So, not many.
- Will gluten-free help me if I don't have celiac disease? Probably not, but it's possible. I'd need to do a double-blind experiment on myself to find out if I'd benefit.
- Would "going paleo" and avoiding sugar, grains, beans, and dairy be of benefit to me? If I balanced it properly I can't see the harm, but where's the evidence that it's the best or necessary?
- Should I test myself for food intolerances and adjust my diet accordingly? Probably not. There's not much evidence the results of intolerance tests mean much.
- Should I avoid artificial ingredients? There's some evidence that specific artificial compounds might be bad, but no evidence I should avoid things simply because they are artificial.
Don't get me wrong: Some or all of these diets have things going for them. I've mentioned before that people generally have crappy diets: people do eat far too much processed flour. People do eat far too much sugar. People do eat far too much dairy. People eat far too much. Most of these diets represent a change for the better from the "Standard American diet". If you change that via one of these diets, you'll do better.
If and when large epidemiological studies are done and show evidence, I'd push my diet in those directions if I thought I'd benefit. But until then, each is just a theory with little reason to believe.
I know why people latch onto these things: it gives people a feeling of control. You hear about someone with cancer or diabetes or heart disease and you feel powerless. Or perhaps you have been gaining weight and are stressed out, or just have low energy. Then this website or book or friend starts talking about how sprouting your grains will give you so much more nutrition or how gluten is affecting your leaky bowel or how our ancestors never ate beans or whatnot and something in your psyche identifies it as a way to gain control. "Ah!" says your brain, "So that's the thing I need to change!"
Again, I'm not immune. I think some of what the paleo people say could be correct. I think simple carbohydrates like sugars and processed grains should be limited. I also wonder if I should worry about lots of other things: dairy, processed meats, saturated/unsaturated fat ratios, omega 3/6 ratios, sodium/potassium ratios, nitrates, BPA, BHT, BHA, residual farm chemicals and drugs in meat, eggs, and dairy, and I'm kind of iffy on artificial flavors and colors.
I don't trust the experts: you can find dozens to support any idea you want. And as a non-expert, I'm am at a loss. There are potentially lots of things to be worried about. I could just eat berries, field greens, and antelope meat cooked over a campfire like my ancestors maybe sort of might have could have possibly done. That would solve most of my worries. It'd also be a huge pain in the ass and be very boring.
So what I do do is this: Lots of vegetables (raw and cooked), lots of raw (and unsweetened) fruit, some nuts and seeds, some meat and/or eggs, some grains or beans. Dairy is optional. Avoid too much sugar, simple carbohydrates, and transfats. The only supplement I take is vitamin D (no other vitamins or "medicinal" herbs or concoctions). I try to limit pre-prepared foods.
There's enough evidence for me that this is healthy, and not enough evidence to go further. So, I don't avoid gluten, wheat, grains, dairy, fruit sugars, or food combinations. I don't pay much attention to the inflammatory index or glycemic index. I don't worry about "toxins" in my food. Based on my brain's high innate precautionary principle, I do try to moderate my consumption of "artificial" ingredients and prepared foods, but I'm not religious about it.
So, what's my point? I'm not too sure, exactly. I guess it's that I'm OK with your eating habits, but I probably won't be trying them anytime soon unless I have evidence.