Since my last post, I’ve had a couple dozen emails asking me whether or not I’ve changed my opinion on the health risk of eating refined carbohydrate sources like rice, oats, wheat, etc. I’ve also had about the same number asking what percentage of a diet should be carbohydrate based. This post is going to try and clarify a bunch of issues related to both those topics.
There’s quite a lot to like about the basic principles of the Paleo diet movement. It encourages people to eat micronutrient dense food and eliminate many foods that cause systemic inflammation via a multitude of different mechanisms. That said, acting like a religious zealot about the Paleo diet means you’ve chosen to ignore some pretty big caveats. Its simply inaccurate to say that it’s impossible to be healthy while including foods that we did not evolve with. In my opinion, some of the foods the Paleo diet excludes are more harmful than others, and equally as important is that people’s specific response to them can vary dramatically. That said, I think the following three groups of foods are worth reducing:
1) Wheat/gluten: There’s pretty good evidence that everyone has some inflammatory response to wheat even if you don’t sense it directly after ingestion (http://www.ncbi.nlm.nih.gov/
2) There’s also pretty good evidence to suggest that avoiding high fructose corn syrup and industrial seed oils AT HIGH DOSES is a good idea as well. However, low doses of fructose and even HFCS in relatively healthy people seem to be tolerated. So again, simply stating to avoid this things at all cost represents blinding yourself from scientific evidence. The key here is likely low, infrequent exposures…
3) There’s also pretty good evidence to suggest that soy is a disruptor of the endocrine response system and should be minimized as well:
So here’s where things get pretty tricky. The Paleo diet also recommends the removal of ALL dairy products and also potatoes as well. The evidence here is much less compelling in my opinion than it is for grains.
65% of the adult population has a reduced ability to process lactose, and may as a result be better off without consuming dairy frequently. The other 35% of people though have the ability to appropriately digest this food. For example, Weston A. Price identified the Swiss Loetschental (among others) that were extremely healthy while eating a diet mostly of milk, cheese and…. bread. If dairy is to be universally considered an unhealthy, inflammatory food, then these types of groups shouldn’t exist, but they do. I think a smarter, more progressive line of thinking is to identify that each persons genes/microbiota place them on a continuum where some people need to avoid dairy completely while others do just fine. Most of us will fall somewhere in the middle and factors such as current body composition, activity level and/or genetic composition determine where on the range we fall.
The Paleo movement against potatoes is where I start to diverge big time. To be fair, many Paleo advocates recognize that there are benefits to potatoes, but others, such as Loren Cordain (the founder of The Paleo Diet) are clearly encamped in the idea that potatoes are harmful because of the saponins and glycoalkaloids they contain.
Again, its pretty easy to find people that eat a potato rich diet and do just fine. The most notable group is the Kitavans, a group of people that eat ~70% of their calories in natural carbohydrates. Despite also having a large percentage of smokers in the population, these people remain extremely healthy and relatively lean. This is completely counter-intuitive to the post from Loren Cordain above.
Formal studies HERE
That said, lets take it to the extreme with a case study of a white middle-aged man living in the U.S. that decided to eat nothing but potatoes for two months (Chris Voigt). On this regimen, he lost about 20 pounds, improved his fasting glucose levels and decreased his triglycerides. Now there’s a bunch of reasons that could have resulted in his improved health, but ultimately the key observation is that an extreme potato diet did NOT make him sick or fat.
The point here is NOT to try to convince you that eating a high-carb potato rich diet is the key to health. In fact, there’s enough evidence to show that ketogenic diets (EXTREMELY low carb) have huge benefits for a number of diseases. The point instead, is that while its convenient to try and make a one-sized fits all diet (it also sells books), there is little evidence to support this approach and its unnecessarily restrictive.
What’s a better approach is to start with some general recommendations, such as:
1) Focus on a diet high in naturally occuring fats using nutrient dense foods. Avoid inflammatory foods by restricting processed grains, HFCS and industrial oils for 30-45 days.
2) Reintroduce foods one at a time and measure your own specific response. If you feel fine with wheat or dairy, etc. then you can probably feel pretty damn healthy following an 80%/20% principle.
This style focuses on eating a nutrient dense, non-inflammatory diet but still allows for flexibility such that you can enjoy life without feeling imprisoned by food choices.
If you are facing serious health conditions like obesity, autoimmune disease or neurological disorders, then the 80/20 principle might not cut it. Someone who is a celiac, or a person with Lupus probably shouldn’t start destroying pizzas and ice cream once a week. Again, I would have these people reset their systems just as I listed above and see what happens with their symptoms. Then more care and attention would be paid to the reintroduction of foods in small doses. Using this approach each person ends up with a diet specific to their genetics,health-status and goals.
A really interesting study was recently published that took an approach similar (though not identical) to what I just described, attempting to reverse Alzheimers. The results were impressive to say the least.