Why is Nutrition Science so Conflicted?
Whenever the topic of healthy foods arises, people like to ask, “What’s the healthiest food, then?”, or “What should I do to get healthy?” Frankly, I don’t have an answer for most people. Nobody does. Our bodies, the environment we live in, and our habits are so incredibly complex that I can’t even begin to narrow down much actionable information, other than good sleep, good activity levels, and a mostly whole-food diet without processed sugars and trans fats. How would one even go about naming the most “healthy” food? What does healthy mean, in this context? Could it be that this superfood is the highest in antioxidants, or vitamins and minerals, or perhaps is the lowest calorie? Maybe it has no saturated fat, or no carbs? In reality, “healthy” means something different for everyone, and that’s the crux of the nutrition debate. How do we decide what the best, most fitting food choices are for the general population, where each individual has their own dietary needs and restrictions?
So, I’d like to go over some broad strokes about why nutrition is such a nebulous term, why nobody seems to agree on anything these days, and why this environment is toxic for the average person just trying to be “healthy”. We’ll mainly go over how to evaluate nutrition claims, and I’ll point you to some good sources at the end. Firstly, let’s address the confusing claims brought by news sources, then get into the clash among science itself.
Let’s imagine a scenario. Perhaps you’re browsing Google, and a link pops up in your sidebar that says “Red wine is proven to stop heart disease!! Click here!!”. So, you click the link and get a computer virus. Womp, womp.
Lol, just kidding. You click the link and get sent to an article written by some larger website - perhaps webMD or Healthline. It tells you about a few studies that looked into this causative relationship, and from what you understand, drinking red wine stops heart disease! Hooray! You can drink all you want, you think.
Well, not so fast. These sites can find articles from anywhere on the Internet, make broad assumptions, and publish whatever the hell they think about it. It’s likely that these new sources sugarcoat and upscale the conclusions of the studies they reference in order to make a click-able article, rather than actually tell you the full conclusion. They may avoid mentioning that the study only evaluated subjects based on if they’re drunk recently, so those that say they are abstinent aren’t required to mention how they’ve had liver poisoning and negative health effects from alcoholism. Perhaps, the reasoning behind this pathway is sketchy. For example, people like to cite resveratrol as the beneficial compound in wine. Except resveratrol is so sparse in red wine, you’d need to drink 1000s of bottles in order to get a positive effect. When you begin to question the methods and communication of the data, their claims often fall apart.
In reality, this claim stemmed from an original study looking at saturated fat consumption and rates of mortality. The researchers saw that French people were an outlier in this data; they ate a lot of saturated fat, yet lived quite long. The red wine claim was added to their original hypothesis to explain away any possible clashing data. This is called an ad-hoc hypothesis, and it is done more often than you’d think. And no, it’s not good; it’s a fallacious rhetorical strategy.
Sometimes, the articles don't even have a reference or a link to the primary research article! This is even worse. How can you evaluate the quality of a claim if there are no sources to speak of?
If you want to get the whole truth, read the source itself. Visit Pubmed, Examine, Nature, JSTOR or any other reputable journal to get full explanations of the data from scientists. I can already hear you saying, “But that shit is so boring and I understand absolutely nothing that those nerds say.” I know, reading scientific papers sucks. Use Word Tune or other similar AI summary applications to give you the broad strokes- this process takes 1 minute longer (tops) than reading some quack website, and you’ll get the information straight up.
Now, onto the conflicting claims. It seems that every month there’s a new health fad. Low-fat, Keto, carnivore, intermittent fasting, vegan, juice cleanses, “alkaline” water, paleo, and hundreds more flood the nutrition space daily. Everyone has their own opinions and preferences, and they’re so certain that their method of eating is the best. One minute, you’ll hear someone squawk about how fruit is bad for you because of its high sugar content, then the next you’ll hear someone else argue that fat is the devil, and that carbs and fruit are the only way to live into your 30s. This is disheartening, if you’re someone who wants to understand how to live a better life. How can you possibly find a way to improve when nobody can agree on what constitutes “improvement” in the first place?
I recently found a book called "The Best Diet: Simple and Evidence based guide to healthy eating" written by a doctor Tsugawa at UCLA, from a video about this topic. I recommend going to watch it: it’s called “Why is Nutrition Science so complicated?” The book claimed that butter is a bad fat, which we’ve all heard time and time again. No surprises there. But, when you actually go to look at the study behind this claim, you butter start to pay attention.
They mainly studied those who ate not only more butter, but higher fat. What does higher-fat often mean for regular folks? That means more processed foods. So, if they’re eating more processed foods, the effect of butter is overshadowed by all the other shit in these unhealthy foods. People who eat processed foods are also more likely to be sedentary, to smoke or use drugs, and neglect their sleep. These other factors are highly correlated to negative health outcomes, yet they weren’t controlled for in the experiment. Without this knowledge, you’d see the broad claim that butter=bad and believe it at face value. In reality, eating one “bad” food isn’t going to screw up your health.
This book also brings up a very often debated topic: Eggs. The book recommends limiting your egg intake to only one a day. Ok, again, we’ve heard this before. But when you actually look at the study, the carbohydrates given to those in the egg-positive group were primarily from table sugar! The effect of sugar has actually been proven in the body, and it’s n(egg)ative*. So, if you’re trying to look at the health effects of eggs, but give them something arguably worse, how will you differentiate between the effects of the eggs and the effects of the sugar? Short answer-you can’t. All health aspects are intertwined. It’s like if you were trying to assess the quality of life of those getting slightly less sleep than a control group. You wake them up 30 minutes earlier than their counterparts, and ask them various questions about how they feel. But, you fail to mention in your procedure that you also blasted air horns into the rooms of the earlier wake-up group at various hours of the night. Obviously their sleep quality will go to shit, but did the wake-up time affect this outcome? You’ll never know.
Biology is incredibly complicated, and it’s nigh impossible to isolate the effect of one food or gene on disease risk. Each choice we make is intertwined with thousands of others. Another example is the claim that protein raises insulin levels in people on a keto diet. That sounds bad, right? We don’t want our insulin to be too high for too long, else we become insulin-insensitive, which is a primary driver for obesity alongside calorie surplus. Seeing this claim, we need to put our thinking caps on. Does protein by itself reliably raise insulin levels?
This has been tested, actually (in dogs, so take this with a grain of salt). Dogs receiving an infusion of glucose get spikes in their insulin levels when given the amino acid (protein) alanine, but dogs not receiving glucose did not. So, perhaps protein plus carbs gives an insulin spike, but carbs alone give a spike anyway! This makes sense; eating chicken tenders with a side of chips and sugary ketchup will elicit a much different blood sugar response than eating, say, a chicken breast on a bed of greens.
Now, back to the whole “is fat bad” debate. Dave Feldman, an independent lipid researcher, developed the Lipid Energy Model, which says that high HDL and low triglycerides are best to prevent heart disease. Just as an aside, LDL stands for low-density lipoproteins, and HDL stands for high-density lipoproteins. We want as little LDL in our blood as possible, as the low-density stuff clogs our arteries more. That makes sense logically- something that is less dense requires less of it to fill a space.
This concept is most used to refer to eggs. A meta analysis of 3 studies found that high levels of egg consumption were associated with increased risk for type 2 diabetes, but another study found no such association. In another meta-analysis, those who ate 1 egg per day or more were 42% more likely to develop type 2 diabetes than those who never consumed eggs. However, the studies used in this meta-analysis did not adjust for potential confounding variables, like the ones we discussed before.
The theory that fat and cholesterol cause heart disease is based on research that shows that feeding cholesterol to rabbits causes high blood cholesterol and atherosclerosis. Although this data may be used to design further studies, we simply cannot use animal studies to make concrete conclusions about human biology. Model organisms are not very diverse, and their bodily processes are quite different from our own.
Mice are often the animals we use to test substances on. The pharmaceutical industry knows that mice models are not always good models, and that they have to do early stage pre-clinical work on cell lines and mice, and then move on to canines and apes, and then start human trials. Many times, the results seen in mice are not replicated in humans.
An example of this is the uproar over aspartame and mice. Mice were fed aspartame, the artificial sweetener used in your average Diet Coke, and they died consistently. This is a scary result until you consider that mice are much more sensitive to aspartame than we are, and they were fed the equivalent of 10,000+ Diet Coke cans worth of aspartame in one sitting.
Another example is an experiment by Lewis Dahl. He fed rats a high salt diet and found that some developed high blood pressure. Nothing new there. He then selectively bred rats that were genetically sensitive to salt and found that half of these salt sensitive rats died. And, I mean…yeah. That makes sense. He made a substance many times more toxic to his model organism, and wondered why they died.
Also, a compound in a food can be found to cause disease, but does that mean that the food itself causes the disease? We need to consider the concentration of that substance in the food, how often you eat it, etc. Technically, there are trace amounts of mercury and radioactive materials in any and all water you drink. Is it then your plan to stop drinking water in order to avoid these heavy metals? I would surely hope not.
When analyzing evidence for a claim, consider how existing ideas can influence the research in a way that biases the research towards acting as evidence for that idea. This is why funding for scientific research can be tricky. If you’re a cigarette company, you’ll want to fund the scientists who will prove that smoking isn’t unhealthy. The same has been repeatedly done in the meat industry. Red meat industry lobbyists will reach out to research organizations and offer a large sum of money in exchange for positive research outcomes about meat. The researchers then have to compose a study that will allow for meat consumption to look good in comparison to an alternative. I’m not joking when I say that red meat consumption has been compared to eating literally straight butter or sugar in these studies, as if that’s some sort of gotcha to say “hey, meat isn’t so bad after all!” Like Christ, I’d hope red meat is healthier than eating a stick of butter.
They assume that readers won’t actually read the studies that allow for their ridiculous claims. So, it’s on us to get into the weeds of nutrition research and learn the real results of this research. When you’re looking to make a change to your health, ask yourself, “What am I really looking for? What does “healthy” mean to me?” For some, it could be to get more active and lose some weight. For others, they may want to lower their blood pressure or increase their insulin sensitivity. Your nutrition needs vary greatly based on all of these factors, and the only way to make informed choices is to speak to a professional. Ask your doctor what the best course of action for you is. There are many ways to live a healthy life, so don’t fret the small details. Do what works for you, and talk to an expert.
Citations:
Some great sources:
*Read Robert Lustig’s work out of UCSF to learn more about this.
And, anyway, here’s a list of some very nutritious foods to incorporate into your diet, with reasons why:
Salmon: they have lots of fatty acids, great for organ function. Also has good protein.
Kale: Rich in vitamins, antioxidants, and phytoactive compounds. Roast it if raw tastes bad to you.
Greek Yogurt: extremely high protein, microbiota-feeding probiotics and prebiotics, low saturated fat, plus calcium, vitamin D and B12…it’s great. Try it. My favorite food.
Seaweed: Great source of iodine, known for importance in thyroid function.
Shellfish: A great source of protein and B vitamins, like vitamin B-12. Also provide vitamin C, selenium and iron, important for many bodily functions.
Berries: high fiber and antioxidants, and lower sugar among fruits. They are also delicious. Raspberries in particular are great for sugar to fiber content, only 33 calories per 100g.
Eggs: very high in nutrients such as choline and lutein, important in eye health.
Potatoes: a great source of potassium, magnesium, iron, copper, and manganese. Also the most filling carbohydrate on the Glycemic index.
Liver: No, you don’t have to live primal to make this work. Liver has vitamin B12, vitamin B5, vitamin B6, niacin, folate (a b vitamin), vitamin B2, vitamin A, copper, iron, phosphorus, zinc, and selenium. You don’t know what all of those do, needless to say it’s as close to a superfood as you can get.
Garlic: High in vitamins C, B1 and B6, calcium, potassium, copper, manganese and selenium. Also very delicious.
Avocado: great source of healthy unsaturated fats. Also a great source of vitamin K, E,
Bone broth: an excellent source of collagen, which is important for skin and joint health. Great to use for soups and very high protein.
Black beans: cheap and high in protein and fiber, they’re great for budgets. Also have lots of iron.
Mushrooms are a great source of fiber, B vitamins, copper and selenium.
Tomatoes have lycopene, a great antioxidant. Also have vitamin C, K, potassium and folate.
Green beans are an underrated source of vitamin C, packing in 27% of the RDA in a single cup. They’re also high in iron, vitamin B6, magnesium, and calcium.
Carrots: their color is due to Beta-carotene, an antioxidant that the body converts to vitamins. Carrots are also abundant in fiber, vitamin K1, and potassium.
Bell peppers are akin to oranges in the vitamin C department. Sweet bell peppers are especially nutritious so choose the warm-coloured varieties to reap the most benefits. A single bell pepper boasts 253% of the RDA for vitamin C as well as vitamin B6, vitamin K1, potassium, folate, vitamin E, and beta-carotene (or vitamin A!).
Raw cacao is a powder with a rich chocolate flavor without the sweetness. Its most notable benefit is flavanols – a powerful antioxidant. One particular flavanol – epicatechin – is thought to boost brain function. It also contains magnesium, iron, calcium, potassium, and phosphorus.
Pumpkin Seeds: A single ounce contains a host of nutrients such as 30-40% of the RDA for magnesium, phosphorus , and manganese. They also have a good deal of iron, zinc, copper, and vitamin K. Plus, they’re chock full of healthy fats.
Chia seeds have a surprising amount of nutrient-density from a single serving of two tablespoons including 12-25% of the RDA for iron, fiber, calcium, magnesium, phosphorus, zinc, vitamin B1, vitamin B3, and omega-3 fatty acids.
Arugula/Rocket: Dark leafy greens are great for your health across the board, but the more delicate salad greens such as arugula stand out as well. It’s rich with antioxidants, calcium, potassium, vitamin C, vitamin A, vitamin K, and folate.
Lentils are a good source of fiber and protein. They’re also high in iron, selenium, and folate. They’re also rich in phenols, an antioxidant.
Apples come into the rank as an easy snack that can add a lot of nutrition to your day. They’re fibrous and watery which make them filling, especially when paired with a fat to help you absorb the vitamins and minerals. They’re high in vitamin C, copper, potassium, and vitamin K.
Amaranth is an underrated gluten-free grain rich in antioxidants such as gallic acid and vanillic acid. It also provides 105% of the RDA for manganese, 40% of the RDA for magnesium, 36% of your daily phosphorus needs, and 29% of the iron you need making it a good meat alternative for those who are iron deficient. It also has notable amounts of selenium and copper.
Quinoa is unique because it’s a plant food and also a complete protein meaning it contains all the essential amino acids our body doesn’t make on its own. It also contains vitamin C, vitamin K, folate, vitamin E, magnesium, thiamine, and fiber.
Tempeh is an excellent source of plant protein made from soy which is a complete protein too. It’s also fermented providing those good gut-healthy bacteria. Tempeh also contains iron, calcium, a good complex of B vitamins, phosphorus, magnesium, and manganese.
Oats are a filling and highly customisable breakfast option with loads of nutrients. They’re high in minerals such as phosphorus, magnesium, copper, and iron. Plus, they contain B vitamins, fiber, and even contain some protein.
Walnuts are incredibly antioxidant rich as a result of being high in vitamin E, melatonin, and polyphenols which could reduce cholesterol levels. They’re also tremendously high in omega-3 fatty acids.
Sources for this: Look up nutrition facts for these foods lol
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