|The Updated USDA Food Pyramid: the worst cluster... of nutrition information ever produced. This article is inspired by the same desire to present an opinion on nutrition, but attempts to do it in such a way as to make sense.|
I’m going to briefly tell you about how I personally think about nutrition. It represents my present opinion after several years of schooling and thinking about these things. It presently lacks thorough citations (which I hope to add later).
The biggest problem with understanding nutrition is that it is complex. We like to talk about “scientific” nutrition, but that’s mostly hooey. There are simply not enough human beings on the planet to figure out how all the multitude of nutrients really work together for long-term health. If you had a trillion trillion people, a thousand lifetimes (and no ethics) you’d make some good progress. As it is, our understanding of human nutrition is pretty rudimentary and there are few things that are rock solid. There are certainly many different things which can be gleaned from science, but we are very, very far away from understanding nutrition or even being able to confidently recommend a particular diet.
As far as I can tell, the following is a list of things I’m pretty confident are true and so will build my diet around:
1) People need to eat enough calories to survive; weight gain or loss roughly follows calorie consumption
2) People need to eat at least some protein (including all 9 essential amino acids)
3) Saturated fat is bad for you, polyunsaturated fat is OK, and monounsaturated fat is good
4) Vegetables are good for you (including their vitamins and minerals)
Here are a few more things I believe, but have not been rigorously proved true:
5) Low glycemic index foods are good for you; high glycemic index food makes you feel crappy and probably causes Metabolic syndrome (hypertension, diabetes, high cholesterol).
6) Flavorful things are probably good for you. Spices, smelly vegetables (like garlic) and tea all have antioxidants (and probably a million other things that are good for you that we haven’t discovered yet). So include them.
So six guidelines for diet: 1) Calories 2) Protein 3) Good fats 4) Veggies 5) Low glycemic index 6) Spices. If that’s too many, try Michael Pollan’s three: “Eat food. Not too much. Mostly plants.”
Notice what’s NOT on this list: low-fat diets, cholesterol, organic food, eating according to the food pyramid, Atkins, South Beach, high vitamin _____. These things all may or may not be good for us.
Now what about the million claims about “a study shows X is good for you”? This suffers from what I’ll call the Jelly Bean Effect (after this). If you do enough studies, you’re bound to get positive results. For most scientific studies of the nutrition sort, even though a study shows a link between X and Y (“scientists say X causes Y!”), it’s more likely the statement is false than true (for the statistically minded, see the JPA Ioannidis paper “Why Most Published Research Findings are False”). So we’re left with very few things which have turned up positive time and time again that we can be pretty (but not totally) confident about.
Another big thing I’m not including in my diet is variety. One thing I noticed when travelling abroad is that food variety was not something that was really valued. When I was in Kenya, every restaurant served the same ‘lunch’: boiled beef (nyama), cooked greens (sukuma wiki), and corn paste (ugali). Most families would eat this for dinner (but often sans beef, because of cost). The American objection, “But we had that last night!” was far from the Kenyan mind. My friend told me a story of his time in India when he asked a coworker, “What did you have for dinner last night?” The man responded calmly, “Dal.” He asked, “What are you planning to have for dinner tonight?” The man, used to strange American questions, responded, “Dal.” It turned out the man ate dal for dinner every night.
And why not? Is there some biological impulse which demands that we eat something different every single day of our lives? Why do we “get sick of” foods that are otherwise good? That is the topic for another blog (my guess is cultural suggestibility). But the bottom line is this: it would seem that most humans get along just fine without variety. And this is a huge relief for someone trying to re-learn how to eat. Learning enough food-stamp-compliant recipes is difficult. So I’m starting with one.