I may have the opportunity to collaborate on a randomized, controlled study of the paleo diet. Is there any advice you would want to give, to make sure we avoid common pitfalls or misunderstandings? Are there flaws you've seen in past diet studies that we should watch out for? Here are some givens:
- We'd be taking American adults with some kind of chronic health condition and randomizing them to go on either a paleo diet or some kind of conventional wisdom diet. We'd follow them for at least 4 months to get bloodwork and health outcomes.
- Participants would get support and advice on following the diet, but ultimately it's up to them (no standardized meals or metabolic ward studies).
- We would get some basic data on whether people were actually eating the diet they were assigned to.
- We'd be sticking to pretty simple, food-focused guidelines. I'd roughly sum them up as: 1) Eat real food. 2) No dairy, grains, or legumes. 3) Don't be scared of fat (appropriately selected).
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Observational studies (correlation does not mean causation, good for generating ideas, not proving causality).
Food frequency diaries (most individuals have poor recall). Even daily food logs can vary unless one is weighing every gram of food they put into their mouths.
"Eat real food." Scientifically doesn't mean much. Breakdown should be highly standardized %s of lipids, carbohydrates, and protein. Sourced from real food, not concoctions or "chow" in any sort of manner.
Ideal experiment: Double blind, double cross-over randomized trials with standardized meals in a metabolic ward. Even then, causality is difficult to establish, but such is the nature of science.
Since most people serious about paleo take it beyond "don't be scared of fat" I'd suggest being a little more straight forward: eat lots of fat.
Be specific: no industrially processed seed oils, lots of olive, coconut, and animal fats, a little from nuts and avocados...
I don't know the constraints of the study but if it's just another self-reporting set up, then it fails where so many other studies have. At the very least, participants should be asked to try and log what they eat in a daily food journal. If you're just asking at the end of the month "so, did you eat like we said to?" then you'll get quite a lot of reporting bias.
I'm assuming also that your dietary counseling will get reasonably specific without overwhelming or being too restrictive. They should be eating plenty of fresh veggies, for instance, and at least a bit of fruit and tubers. They should be told to avoid mainstream coffee creamers, opting for coconut cream or heavy whipping cream and MAYBE a dash of honey.
You should print out a cheat sheet or simplified infographic to guid daily eating. I personally like the PHD one:
1) Eat real food - This statement is meaningless.
2) No dairy, grains, or legumes. Okay.. So a dairy free, grain free, legume free diet then is what you're studying.
3) Don't be scared of fat. This is incredibly vague. What does this even mean? I'm not scared of fat and I don't eat very much fat. If I'm not 'scared' of fat then does that mean I'd indulge in it?
Honestly without more specifics as to what is and isn't allowed, what specific macros you'll be testing for, types of fat, etc I don't think you're going to have anything more than a jumbled mess of (probably small sample sized) data at the end of this study.
If you aren't very specific in what parameters you'll be changing and what parameters you'll be measuring then your study is going to be a pile of garbage when you finish. Maybe these parameters are already defined, if so please elaborate on them in your question so I can modify my answer/recommendation.
Seriously I'm not trying to be harsh, but I've read a ton of medical journals and am a high ranking member here on PH, this is my honest opinion.
I'm glad you didn't overstructure the paleo part. It's voluntary compliance, and requiring grass fed liver and kale reduces compliance. But be as specific as you can be in what you want to accomplish. If you don't have a specific diet for your control group then I suggest letting them carry on with whatever they're doing. That way it becomes paleo vs whatever made them sick and not paleo vs med. Since the purpose is not weight loss I'd suggest letting both groups eat and exercise ad libitum. Above all have specific markers to measure against, such as systolic blood pressure, HDL, A1C, fasting blood glucose, etc. The more the study is shotgunned the less it will show.
And since most paleos eat butter you should allow it.
It would be nice to see a study on health metrics modulated by food choices actually study the food choices. Any chance you can publish the logs of what the participants eat, when they eat it, and how this affects their health metrics? (food weights + micro/macro nutrient averages w/ timestamps.) This would be much more useful than seeing the results that follow from the advice to 'eat natural food and avoid grass-fed ghee and raw dairy / fermented low-glycemic grains / soaked and properly prepared legumes' when told to chronically ill people on a suboptimal diet and followed for a few months.
I think a lot of published paleo diet trials have utilized more restrictive diets than seems to be the norm. They favor lean meats for example, which seems to be quite contra to what you'll hear most practitioners advocate. In many of the studies saturated fat intake was quite low, often lower than the control diet. Given the common belief that SF is unhealthy I think helping to control for a significant difference in this respect would be good.
Perhaps allowing, maybe even supplying a cooking fat like coconut oil could help with this, I don't know. I think something like that might also help with dietary adherence as well.
Anyway, best of luck to ya.