The best diet ever

If you do not have time to read this one, here is the entire post in three words. Test, do not guess.

I get asked, every week, what the best diet is. Every diet camp wants me to agree with them. Paleo people want me to say their pattern is genetically optimal. Vegans want me to say their pattern is metabolically optimal. Mediterranean people want me to say their pattern is the evidence-backed winner. Keto people want me to say their pattern is the metabolic reset everyone needs. Here is what I actually think, after twenty years of looking at lab work in real patients and reading more diet studies than I care to count.

The Paleo camp

The Paleo argument is that human genetics has not changed materially since the agricultural revolution, so we are best served by the patterns we ate for the few hundred thousand years before. There is real strength to this argument. Loren Cordain’s work on net endogenous acid production showed that the red-meat-acidifies argument does not hold once you account for vegetable intake. Free-range, grass-finished meat is metabolically different from feedlot grain-fed meat. Most of the negative red meat studies use the latter.

What I will not concede to the Paleo crowd is that you can fully recreate the metabolic environment your ancestors lived in. Your epigenome, microbiome, sleep environment, and activity pattern are all different. You can mimic the food. You cannot mimic the life.

The vegan camp

Plant-based diets, done well, can produce excellent cardiovascular markers, lower inflammation, lower body weight, and lower fasting glucose. The data on those endpoints is real. What concerns me, after testing over a hundred long-term vegetarians and vegans for omega-3 status, is the consistent failure to achieve a healthy omega-3 index. Plant ALA conversion to EPA and DHA runs around 5 percent in most adults, lower in many. Flax and algae help, but few practitioners take enough.

I will not concede to the vegan crowd that the China Study is a study. It is a curated set of correlations marketed as a study. Food and Western Disease, the Lindeberg work on the Kitavans, is much closer to what real nutritional anthropology looks like.

What nobody likes hearing

No diet has been tested for direct effects on human longevity. The studies that do exist track surrogate endpoints, biomarkers, intermediate disease incidence, body composition. Long-term population studies are mostly observational and confounded by everything from socioeconomic status to walking habits.

What is also true is that epigenetic individuality means a diet that lands well in one population may land poorly in another. The Okinawan pattern is excellent for Okinawans. It is not necessarily ideal for someone with northern European ancestry, a different gut microbial profile, and a different sun exposure history.

The four tests I actually use

Forget the diet argument for a moment. The diet is the input. The output is what we should be measuring. Here are the four numbers I want from my patients regardless of what they eat:

1. Subjective tolerance. Do you feel good eating it? Digestion, energy, sleep, mood. If any of these are off, the diet is not working for you.
2. Omega-6 to omega-3 ratio, or red blood cell omega-3 index. Aim for a ratio closer to 4:1 or better. Aim for an omega-3 index above 8 percent.
3. 25-hydroxy vitamin D. Aim for 50 to 75 ng/mL. Below 30 is associated with worse outcomes across most categories of disease.
4. Telomere length, particularly percentage of critically short telomeres. If you are going to spend the money on advanced testing, this one tells you the most about cellular aging trajectory. A telomere age six or more years younger than your chronological age is a good sign.

A few honest warnings

Diet alone will not get you to ideal numbers. Sleep, exercise, stress regulation, and supplementation are all part of it. The four tests cost roughly $300 to $1,000 depending on which lab you use and how much your clinician charges to interpret. Most people do them once, get a baseline, and repeat every two to three years, or sooner around significant life changes, dietary change, geographic relocation, new training program, new health diagnosis, new long-term supplement.

The other warning. Most diet studies are either short-term or population-based. Short-term studies miss the deficiencies that show up only after years. Population-based studies are about the average member of that population, which usually is not you.

If you actually run these tests on yourself over a decade, you will know whether your diet is working better than any expert in the world can tell you. That is the version of dietary science that respects you as an adult. The rest is mostly tribal warfare with citations attached.

I currently run a neo-Paleo pattern. Mostly. Whole foods, animal protein, lots of plants, very low refined carbs. The numbers above are how I check whether it is still working. They should be how you check too.

— Doc