New Year, NutritionJan 17, 2019
I find nutrition fascinating. It’s one of the most important research fields given how many people care about its effect on longevity, weight loss, and overall health, but it’s also one of the most difficult areas of science for us to make reliable progress. Part of the problem is that the human body and its metabolism is ridiculously complicated, so it can’t be easily broken down to first principles like physics or chemistry.
As a result, most people are wildly misinformed about some fundamental facts. Here are 9 statements that we know to be true, but that you probably weren’t aware of.
1. Organic foods are a scam.
I’m starting with the topic I feel most passionately about, because it’s something that is simultaneously true and surprising even to people who consider themselves fairly informed: there is NOTHING that makes organic foods better for you or for the environment. To start with, the term “organic” is pretty meaningless. In practice it means that farmers only use pesticides found “naturally,” but of course just because a chemical is found in nature does not make it safe to ingest or better for the environment. (In fact, since organic farming often requires using a less effective array of pesticides, it tends to be less efficient, which means more land and effort needed to achieve equivalent crop yields. In this sense, it’s decidedly worse for the environment).
2. GMO crops are 100% safe
For whatever reason, this one is more familiar to people, possibly because scientists have pushed back against it a bit more. GMOs are definitely safe to eat, and on average, they’re not significantly better or worse for the environment than non-GMO crops. In 2015, Chipotle announced that they will stop serving GMO foods, and I still hate them for it.
At this point people often ask what the harm is in just requiring GMO food to be labeled. More information for the consumer is better right? No. Labels that convey no information mislead consumers into thinking that they’re meaningful, which only perpetuates the problem.
Perhaps you understand both these points, but you still don’t like big companies suing poor farmers over GMO patent disputes. This is not a nutritional debate, but I’d still urge you to read this Quora answer to the question ‘Is Monsanto evil?’ and then re-evaluate how you feel about the industry.
3. You (probably) don’t need dietary supplements
The story of vitamins is as follows: in a laudable effort to understand human nutrition, scientists identified several key organic molecules that humans need for bodily function. Scientists then figured out how to measure vitamin levels from a blood test, and through a combination of pharmaceutical companies smelling some easy money to be had and some overeager researchers, millions of Americans take some form of a vitamin supplement when they don’t need to. You’ve probably heard that taking vitamin D leads to stronger bones; it doesn’t. Maybe you’ve heard that fish oil and its sweet, sweet, omega-3 fatty acids will prevent heart attacks. Dubious. But surely antioxidant supplements will neutralize your free radicals and slow aging right? No.
Look, none of these things will hurt you that badly, but you shouldn’t spend money on things that don’t work. Stop buying dietary supplements.
4. Artificial sweeteners are fine
I drink my coffee with Splenda. You should feel free to do so as well. Artificial sweeteners really are calorie free, but their effect on weight loss is dubious. However, what isn’t in dispute is the simple fact that they don’t cause cancer. In 2015, Pepsi announced it would stop manufacturing its diet sodas with aspartame, but last year they reversed course and added it back. Rejoice for evidence-based product decisions! (even if it was driven entirely by consumers who didn’t like the new taste).
5. High-cholesterol food doesn’t increase your cholesterol
For a long time people worried about eating too many eggs because they’re rich in cholesterol. We now know that this was misguided. The truth is that the level of cholesterol in the food you eat is not associated with your body’s cholesterol level. 85% of your body’s cholesterol is manufactured in-house by your liver, and your baseline level is due almost entirely to genetics. Lifestyle and diet choices can have real impacts on your cholesterol level and your cardiovascular health, but the specific amount of cholesterol in the food you eat doesn’t matter.
6. Most diets can be perfectly healthy… but it’s still really difficult to use them to lose weight
The holy grail of nutrition science is figuring out how to induce long-term weight loss. We still don’t know. In principle, the problem is trivial: you are guaranteed to lose weight if you consume fewer calories than you burn. If someone followed you around for the rest of your life and regulated what food you ate for every meal, you could achieve almost any target weight and maintain it for your whole life. In practice, keeping weight off is incredibly difficult. Several of you probably read this viral New York Times piece about contestants on The Biggest Loser who lost hundreds of pounds on the show and proceeded to gain them back in the months and years afterwards.
So, it’s very hard to use diets to lose weight, but paradoxically, diets are the really the only way we know to do so. (Exercise, while very very good for your long-term health, won’t help with weight loss). There is a silver lining: most diets are perfectly fine–even the weird one where you only eat meat that is strangely popular among cryptocurrency enthusiasts. The importance of the specific foods in your diet is dwarfed by (a) your ability to adhere to the diet over a long period of time, and (b) the diet’s daily caloric value.
7. I seriously doubt that you are “gluten-sensitive”
There are some people who can’t eat gluten. These people have celiac disease. There are other people who think that they can’t eat gluten. These people think they have “non-celiac gluten sensitivity” but are in all likelihood just wrong. Then there are people who believe that avoiding gluten will make them healthier. These people are definitely wrong. Look, gluten is amazing: it’s what gives structure to bread, pizza, pasta. If you can eat gluten, you should enjoy it, not avoid it! I highly recommend this Freakonomics podcast about The Demonization of Gluten.
8. Soy doesn’t increase your estrogen levels
If you’re familiar with the term “soy boy,” then regrettably, you’ve probably also heard of this myth. The claim is that soy (in any of its forms) is high in estrogen, which, when consumed, will disrupt your body’s hormonal levels. First, soy actually doesn’t contain any estrogen. However, it is high in “phytoestrogens” which are structurally similar plant-based compounds that that sometimes have the same effect as estrogen, and other times have the opposite effect . Second, soybeans aren’t the only food with these compounds; nuts, oilseeds, and even beer are rich in phytoestrogens (and I can guarantee you’ve never heard someone worry that drinking too much beer will give them breasts).
As far as we know, the cumulative effect of these phytoestrogens is basically nothing. Admittedly, there aren’t a ton of studies out there about this topic, partly because the myth is relatively new. There’s definitely room for more research to be done in this space, but there is currently no good reason to avoid soy-based products.
9. Coffee is non-trivially good for you
Let’s close with some good news: there exists a mass-produced, mass-consumed, perfectly safe drug that modestly, but statistically significantly reduces the risk of heart disease. Coffee is honestly the closest thing we have to a miracle substance: on top of increasing energy and memory function, there’s limited evidence that it will also literally extend your life. There is no amount of coffee that you can feasibly consume that is unhealthy, and all indications are that the more you drink, the stronger the health effect is.
The one downside is that coffee (or rather, caffeine) results in physical dependence (distinct from addiction), meaning that you’ll experience mild but annoying withdrawal symptoms if you stop or significantly decrease your consumption.
Closing thoughts: where to get accurate nutrition reporting
The media handles nutrition science badly. People care about weight loss so they’re happy to click on just about anything, so sites are more than happy to write up the results of one individual research paper about chocolate being amazing for you or açaí berries curing cancer. These articles are terrible and misinforming. So what should you read instead? Here are my recommendations:
- Anything by Julia Belluz at Vox is evidence-based and excellent
- Anything by Aaron Carroll at the New York Times is similarly great
- Aaron also has a Youtube series and a podcast both of which are quite good
In general, you should discount any article that is based on a single study. You really should only care about meta-analyses of randomized controlled trials.
Sincere thanks to Kimberli Zhong and Varun Mohan for proofreading and correcting earlier drafts of this post.