I recently had a conversation with my sister-in-law, Dr. Cathy Cheng, who is a very good physician, takes a holistic view of health, and genuinely cares for her patients. We talked about the confusion I have over nutritional advice, and how I feel that many of my nutritional questions should have answers by now. At some level the medical and scientific communities have failed us.
Dr. Cheng gave our conversation some thought and wrote about it on her blog. Though I agree with almost everything she wrote, it doesn't address my frustration. I'll attempt to articulate why by giving a bit of background, the advice that I'd love to have definitive answers on, my current thinking on the subject, and the resources I find compelling.
I've followed nutritional thought for many years. I took a few courses while at CU Boulder on nutrition and kinesiology, and have kept up with the conversation through articles and podcasts in the decade since college. I'm not trying to paint myself as an expert, I'm certainly not. In fact, that is the point of this post. As a non-expert, but interested layman in the nutritional arena, I have to rely on outside information to make decisions. As important as diet is to health, disease prevention, and performance, I want to understand the best possible advice.
Dr. Cheng's Article
I agree with most of Dr. Cheng's article. For the general U.S. population, who is largely overweight and sedentary, her advice is sound. Cutting out pizza, fast food, and easy cheap snack foods is a huge win. As a population we should start there. She also wisely mentions working on other health factors such as exercise, sleep, stress management, and relationships. I 100% agree.
One part of her article that I would contest is that none of the sources that I trust (and list below) claim to have the "one method for lifelong healthy eating." That's too strong of language. They're not selling a diet, they're trying to find answers and push the science forward.
I would also contest that you have to be in the top 1% to go deeper than her advice. I don't consider myself in the top 1% of athletic performance or dietary cleanliness, far from it. I think it's more likely that this is an instance of the 80/20 rule, where 80% of people are compelled and satisfied with her advice, and 20% want to go deeper. I'm one who wants to go deeper.
So What's the Problem?
While I agree with her advice, it doesn't address my frustration. "The best diet is the one you can stick to" is a cop out, it's weak, it's too generic, it's unsatisfying. It might be fine at a population level, but I'm looking for more. I'd like to know what the best advice is if we flip the statement to be - assume you have the will-power, motivation, and long-term perspective to follow any diet, what then should we eat? What should we absolutely not eat?
That's a much more interesting question.
I'd also like to consider more than just weight and waistline. Those are proxies for health, but shouldn't be the goal. Let's think about diet for all aspects of health:
- Disease prevention for cancer, cardiovascular disease, dementia, arthritis, etc.
- Fuel for performance - running, cross-fit, soccer, yoga, etc.
- Energy for daily life - being able bike to work, keeping up with a two year old, having energy to do meaningful work.
- If I can slim down a bit in the process, great!
Is it possible that the above aspects are actually in conflict with each other? Could "carbo-loading" for a race or workout be counter-productive to cancer prevention or brain health?
Complicating the Matter
I remember US Department of Agriculture's food pyramid from 1992, which largely promoted a diet based on bread, cereal, rice, and pasta, and which also recommended using fats and oils sparingly. The food pyramid lasted in some form for around 19 years to 2011. I don't think it's too controversial at this point to say that this was bad advice, even dangerous advice. How can this happen? It was either advice based on bad science, incomplete science, or there are outside factors, like funding from food industry interests that cloud the recommendations. At the very least, these government and large medical agencies, including the Food and Drug Administration, and the American Heart Association have a bad track record, and should be listened to with great skepticism.
I also remember (and still hear) the advice that a calorie is a calorie is a calorie, and that weight-loss is a simple formula of calories consumed versus calories expended. I think this was, and is, more bad advice.
So while I no longer trust the larger government agencies and associations to provide unbiased guidance, I do find there are several well-credentialed scientists, doctors, and researchers out there that are doing compelling work. But I'm left to piecing together my own unifying theory, based on input after input to give me direction in formulating my own diet.
- Are grains good or bad? Oatmeal is a staple of endurance athletes, quinoa is awesome, right? The concept of grain brain from Dr. David Perlmutter suggests otherwise, and Dr. Steven Gundry's concept of lectins would also advice against these foods.
- Is intermittent fasting okay? - Is it wise to confine eating to a smaller block of time in the day, and let your body fast for 12-16 hours a day, or should we really fuel up for the day in the morning?
- Is being fat adapted or metabolically flexible worth pursuing? - Can you be an endurance athlete on a low carb diet? Is it healthy?
- Is fruit good or bad? - Is fruit just another vehicle for too much sugar, or do the positive elements outweigh the negative? Maybe remove certain fruits like bananas, and keep all berries?
- Is butter and other natural saturated fats okay, even good? - There seems to be good evidence that it was bad science to recommend against cholesterol and saturated fat. Saturated fat coupled with sugar seems very bad, but how about saturated fat alone?
- Is coconut oil good or bad? - I've come to believe coconut oil is basically a superfood. It's certainly universally praised from the my trusted sources. However, there are those in the saturated fat camp, including the AHA that claim otherwise.
- What about lectins? - Is it possible not all vegetables are good for us? Dr. Steven Gundry has built a platform based on removing lectins from the diet. I don't know the answer to this.
- Should you choose white or brown rice? - Is brown rice any better than white? They are both mostly carbs, and brown is just harder to digest. I don't know the answer to this. Many would say to not eat rice at all.
- Is dairy good or bad? - Is milk just another vehicle for too much sugar? How about cheese? How about yogurt?
- Is gluten something that only those with celiac disease need to consider? - I've repeatedly heard both sides of this debate. I'm inclined to believe that most people would benefit from reducing grain in general, with the caveat that they replace the fiber some other way. But, again, I don't know the answer to this.
- Whole30, good or bad? - I've done Whole30 twice, and I'm inclined to think that it's a very good way to eat. However, I've read plenty of articles claiming that whole grains such as oatmeal and beans/legumes/lentils are a necessary part of a long-term healthy diet.
- What about a ketogenic diet? - Is ketosis something that I should investigate for cancer prevention, or potentially physical performance benefits? The concept seems promising, though incredibly strict and hard to follow for everyday life. Maybe this is something to incorporate for short periods a few times a year? How does a ketogenic diet play with endurance training such as ultra-distance trail running?
As a reasonably well-educated person who follows the nutritional conversation, and I still don't know answers to many of these seemingly easy, or at least basic questions. Perhaps there are no easy answers.
My Current Thinking
I'm firmly in the lower carb, higher fat diet camp. I see all vegetables as good, and don't worry too much about the lectins. I don't limit fruits, yet. I certainly don't limit berries. I still eat beans and lentils. I still eat oatmeal when powering up for a longer workout. I think the intermittent fasting is probably wise, and I'm currently experimenting with it. I don't worry about butter. I don't worry about cholesterol from eggs. I stay away from vegetable, canola, and soybean oils, as well as soy products, when possible. I still eat dairy, but it's much more limited now, and I try for full-fat, lower sugar options. I opt for unsweetened almond milk instead of cow's milk. I eat good quality red meat without concern for health (though the environmental concerns are a different topic all together). I'm intrigued by Ketosis.
I've also realized that it is just part of the scientific process to get things almost exactly backwards for two decades before self correction. This is especially true in the inexact sciences like nutrition and biology. Running valid experiments is hard, expensive, and messy, and we need to allow for some room to be wrong. Saying we should have consensus on these questions is kind of like saying all economists should agree on economic policy.
The corollary to that statement is that it is quite possible that my current understanding, based off of what I hear and trust, could be totally wrong. I hope it isn't, but it wouldn't surprise me. That is the danger of the USDA, FDA, AHA, and diet fads putting out bad advice, and then being reluctant to admit when things are wrong - we lose confidence in all advice. We wait for the current advice to be wrong. All of this thought and research and human history, and we still are only mildly confident in what makes up a healthy diet. I find that frustrating.
Resources Informing My Opinions
Much of my current nutritional thinking is well summarized in the resources below.
- Tim Ferris with Dr. Dom D'Agostino - This podcast opened my eyes to the concept of ketosis. It's a great primer.
- Tim Ferriss with Dr. Peter Attia - The two podcasts together expand further on ketosis, plus issues around a calorie is a calorie.
- Sam Harris with Gary Taubes - A very interesting conversation about politics in current nutritional recommendations.
- Shawn Stevenson with Dr. Mark Hyman - A great conversation on current nutritional advice.
- Shawn Stevenson with Dr. David Perlmutter - Another great conversation on current nutritional advice.
- Shawn Stevenson with Dr. Steven Gundry - An introduction to lectins.