A new major and important dietary study has been released. It’s called PURE, and I think it’s going to be a big factor in reshaping how we think about our diets. This isn’t the first time I’ve written on the subject (a good piece on my views is here) and won’t be the last, I’m sure.
A good overview of the study was published in Science Daily. A really good non-jargon-filled perspective on it is in the Irish Times. The full study isn’t online for open viewing but was in Lancet behind a paywall, but I was able to grab a copy and go through it.
My take on this: the study is large (135,000 people studied) across 18 countries in 5 regions across the planet and on average they were followed for five years. During that time the study population had 5796 deaths and 4784 major cardiovascular disease events. The research seems well-designed and well-controlled and the results seem statistically valid and significant. There are some areas that deserve more study (the main one: impact of a patients economic status and whether low-income issues drive results more than the typical high-carb diet of low-income people) but the results to be unambiguous for the general results.
What they found
Their summary of the findings says it all:
High carbohydrate intake was associated with higher risk of total mortality, whereas total fat and individual types of fat were related to lower total mortality. Total fat and types of fat were not associated with cardiovascular disease, myocardial infarction, or cardiovascular disease mortality, whereas saturated fat had an inverse association with stroke. Global dietary guidelines should be reconsidered in light of these findings.
The TL;DR of the study
If you follow current dietary guidelines of eating a high carb diet while restricting fats (especially fats) out of your diet, you die sooner than if you eat a diet with lower carbs and higher fats in it.
Your risk of dying of heart disease does go down somewhat, but your risk of dying of other things, especially stroke, goes up.
If you don’t have enough saturated fat in your diet, your risk of stroke increases massively.
Current recommendations are that we eat 4-8 services (400-800 grams) of fruits, vegetables and legumes. The study indicates a recommendation of 3-4 servings (350-500) grams a day is better for you.
Basically, my take on this piece is this: high carbohydrate consumption is bad for you; reducing protein and fats (saturated and unsaturated) was the recommendation for reducing heart disease; it doesn’t actually make you live longer, it just kills you in different ways. That seems stupid. If you follow those standards very closely, chances are it kills you younger than if you didn’t.
A few years back I became convinced that the high carb diet was unhealthy and linked to the obesity and diabetes epidemics we’re seeing in industrialized countries — and there’s more and more data showing those links, but there’s still no scientific consensus. I think this study pushes that forward as well.
Because of that, I made changes in my diet: I try to eat 25-35% of my calories as carbohydrates, and split the rest between fats and proteins. I stopped worrying about or paying attention to saturated fats. I try to eat complex carbohydrates, and I try to avoid heavily processed carbs; in practice that means brown rices instead of white, whole wheat instead of white flour, and keeping things that are pre-made with white flour (crackers etc) to a minimum. It also means watching sugars; when I eat sweets, I try to do them in a mixture with fats to slow digestion — fortunately, I really like ice cream.
There is a growing movement to re-think dietary guidelines away from the existing carb-centric diet, but it’s going to take time to convince the establishment it needs to be done. A lot of the data and the fight going on over it is talked about in my piece I linked to at the top of this one, so I won’t repeat it.
What I do know is personally, I’ve taken off 60 pounds from my max, 45 in the last year, and in the last month, been able to reduce my insulin by about 5% while maintaining my numbers. My diet is a part of how I’ve made that happen, but it’s part of a larger and complex set of things I’ve worked on with my doctor.
I’ve long felt that the existing standards were wrong: they basically tell you to eat lots of carbs to stay healthy — until you turn diabetic, and then to be healthy you have to do the opposite. Combine that with the massive increase in the rates of diabetes in our society, and its easy to come up with the thought that maybe lots of carbs simply isn’t a good idea in the first place.
This PURE study is a good, well-thought-out and large study that backs that idea with real numbers, and those numbers say quite clearly the existing dietary recommendations are wrong and have to be fixed.
Worth talking over with your doctor…
p.s: This study also doesn’t seem to show any real advantage to a vegetarian diet, but doesn’t really show any problems with it, either. I also don’t think this study does any positive thing for any of the so-called extreme diets, whether you like Atkins or Ornish or whatever. What seems to be the sweet spot in health and longevity is a more balanced mix.
If you thinking of shifting your diet around, a good start is to think in terms of 1/3 each of Carbohydrates, Protein and Fat, with fat being a reasonable mix of Saturated and unsaturated fats.
Quick note: New study on your gut and mood
One final quick note on another subject: there’s another study out showing that what goes on in your gut can affect your mood and cause anxiety. There’s been a growing thought that the Microbiome (aka, all the bacteria and stuff in your gut) has a much more significant impact in our life and health than we realized, and studies are starting to indicate that this idea is correct. Still a lot of work here to fully understand it, but I expect in the next ten years or so our understanding of gut bacteria and its impact on us is going to affect a lot of health and living ideas.