5 principles for how to eat a healthy diet.

Eggs are condemned as deadly one day then praised as health-food the next. Low fat is in one year, only to be replaced by low carb the next. This apparent flip-flopping in established dietary wisdom, real or perceived, can be frustrating to the point of inducing a sense of futility. I can’t recall the number of times I’ve heard someone say something along the lines of “it doesn’t matter what that dietary study says, they can rig them to prove whatever they want.”

While it is true that our knowledge of what constitutes a healthy diet is limited, we are not ignorant. There are a few non-controversial principles that, if followed, promote good health for most people. Here they are:

Principle 1: Listen to your body. If it makes you feel healthy, it’s probably good for you. If it makes you feel bad, it probably isn’t.
Principle 2: Severely restrict sugars and starches (especially refined). Sugar and refined starch are easily the biggest drivers of disease in our diets. The less of these we eat, the better we’ll feel.
Principle 3: Eat nutritionally dense food. The more essential vitamins, minerals, phytonutrients, fatty acids, and amino acids we eat per calorie the healthier we’ll be. Therefore, the majority of our calories should be sourced from nutritionally dense foods.
Principle 4: Eat seafood or supplement Omega-3’s. EPA and DHA’s impact on our health is as strong as some drugs but most of us are deficient. Nearly all of us should increase our consumption to ensure we are getting an adequate intake.
Principle 5: Consume the rest in moderation. Meat, dairy, eggs, sugary fruit, etc. So long as they don’t make up the majority of our diet, we don’t need to worry about them.

Principle 1: Listen to Your Body

We all have a unique response to food. Food that makes one person feel great can make the next person feel terrible. In the most extreme cases, for example, a negative response to food can present as allergies (ex. Peanuts) or autoimmune disease (ex. Gluten). For others, in contrast, this negative response may manifest more subtly as brain fog, bloating, low energy, skin problems, or anything that makes them feel “a bit off”.

How To Apply

Due to our variable response to what we eat, it’s essential that we pay attention to how food makes us feel so we can eliminate anything that provokes a negative reaction. If eating something makes us feel healthy, it probably is. If it makes us feel bad, however, it probably isn’t and we should eliminate it from our diet.

An elimination diet, such as Whole 30, is an effective tool in finding and removing foods that negatively impact our wellbeing.

Why it Works

Our immune systems are a major source of the variability in our reactions to food.

Each day, our gut is exposed to pounds of food from the outside world and, in that food, pathogens that, without our immune system, would threaten our health. Fortunately, the bulk of our immune system is located in the gut (some estimates reach as high as 70%) where it protects us from those pathogens. Unfortunately, however, our immune system is fallible and it sometimes mistakes food for a harmful invader. When this happens, we develop an autoimmune disease, allergy, or sensitivity to that food.

When this occurs, our body’s reaction to the food, not the food itself, is the problem. As a defending army might accidentally destroy a road protecting from an invader, so too does our immune system inflict collateral damage on our cells. When we repeatedly consume food that our immune system reacts to, that collateral damage can create a state of chronic inflammation that negatively impacts our health and wellbeing. Once we eliminate these foods from our diet, however, our immune system will stop reacting and the symptoms will subside.

Principle 2: Severely Restrict Sugars and Starches (Especially Refined Starch)

Sugar and quickly digested starch (think pasta, bread, and even potatoes) are easily the most unhealthy element of our diets. It is, in large part, thanks to these foods that we have the diseases of modernity–diabetes, heart disease, cancer, obesity, neurodegenerative disease, etc. Consequently, in order to avoid these diseases, we should avoid sugar and refined starch as much as possible.

How To Apply

Before discussing how to avoid sugar and starch, it is important to acknowledge how hard they are to limit. Not only are they delicious, they’re also cheap and essential ingredients for many common foods.

Sugar, for example, is not only found in the obvious places (soda, candy, ice cream, cereal, cookies, donuts, etc.), it’s also added to many foods you might not expect. For example, bread, yogurt, tomato sauce, salad dressing, and granola all frequently include added sugar (even though they taste great without it).

Likewise, easily digested starch is ubiquitous. Everything made with flour (bread, bagels, donuts, crackers, pretzels, noodles, pasta, tortillas, etc) as well as common staples such as white rice, potatoes, yams, and corn should be limited.

The prevalence of sugar and refined starch makes it clear that we are not going to completely eliminate them from our diets. This begs the question: how much is too much?

At the end of the day, that’s an individual decision. I personally allow myself up to 2 meals per week with sugar and/or starch as that keeps my weight, energy, and blood work in an acceptable range. You might allow yourself more or less, depending on your goals. The important thing is not that we eat or don’t eat unhealthy food, but that we do so aware of the consequences.

In my experience, avoiding sugar and starch requires a two-pronged strategy. First, I have learned to cook delicious meals without either. Second, I do not keep sugar, starch, or foods made with them in my home. Together, these tactics help ensure that the majority of my meals are made without either component.

Sugar by another name is still sugar

If you choose to limit your sugar consumption, be mindful that sugar can masquerade on ingredient lists under other names. Dextrose, fructose, sucrose, high fructose corn syrup, agave nectar, honey, molasses, dextrin, and many other names are all basically just sugar synonyms and should be avoided.

Not all food with sugar/starch is created equal

While all foods with sugar and starch have been treated equally up to now, it is important to note that they are not all equivalent. Sugary and starchy foods that are also naturally fibrous and nutrient-dense are preferable to sugary and starchy foods that are not. That means that, if we’re choosing between crackers and whole potatoes, we should pick the potatoes. Similarly, we should prefer bananas to cookies but, if we can have roasted Brussels sprouts instead, we’d be best served by the sprouts.

Artificial Sweetener

If you, like me, love sweet food, I have good news. Erythritol is a zero-calorie sweetener that has a neutral impact on health. I use some every day.

Why it Works

The ways in which sugar and refined starch negatively affect our health fills entire books. In the interest of expediency, I won’t elaborate beyond a short list.

Sugar/starch causes inflammation which increases fatigue, depression, anxiety, and chronic pain.
Sugar/starch reacts with protein and fat to form “Advanced Glycation End Products” which stiffen tissues (blood vessels, heart muscles, etc) and impair their function. In the case of skin, this loss of elasticity causes an aged, wrinkly appearance.
Sugar/starch promote oxidative stress in arterial walls which increases the risk of heart disease and stroke.
Sugar/starch spikes insulin which triggers weight gain and hunger while limiting our ability to mobilize stored fat for energy.

Eliminating sugar and starch eliminates these effects. Admittedly, it matters what foods we replace them with, but pretty much anything is preferable to sugar.

Principle 3: Eat Nutritionally Dense Food

Nutritionally dense foods are those with a low proportion of calories to essential fats, essential amino acids, vitamins, minerals, and phytonutrients. By virtue of this nutritional density, they are the healthiest foods we can eat and they should constitute the majority of our calories.

How To Apply

The primary challenge in applying this principle is in identifying nutritionally dense foods. Fortunately, this can largely be done heuristically and it likely already aligns well with what you think of as healthy.

High Density: Vegetables, Some Nuts/Seeds, Some Fruits, Organ Meats, and Certain Seafoods

Topping the list of nutritionally dense foods are most vegetables, some nuts and seeds, some fruits, organ meat, and Omega-3 rich seafood. These foods are packed with essential nutrients that promote health and wellness and we can eat them freely.

For myself, each day, I eat 5-10 cups of veggies (kale, broccoli, purple cabbage, onions, spinach, broccoli rabe, asparagus, mushrooms, cauliflower, etc.), 700+ calories of nuts and seeds (hemp seeds, pumpkin seeds, macadamia nuts, walnuts, pecans, almonds, etc.), and maybe a handful of fruit (blackberries, raspberries, strawberries, blueberries, etc).

I don’t eat meat but organ meat, such as liver, is very nutritionally dense. The only seafood I consume is oysters, which I discuss further in Principle 4.

Moderate Density: Whole Grains, Legumes, Root Vegetables, Cheese, Eggs, Muscle Meat

Whole grains, legumes, and root vegetables are middling in their nutritional density. They are full of vitamins, minerals, and phytonutrients but tend to be higher in carbohydrates which negatively impacts their net nutrient density.

Likewise, cheese, eggs, and muscle meat are lower in nutritional density due to either having fewer nutrients or more unessential fats.

We can eat these foods in moderation, but they should make up a smaller portion of our calories than the high-density foods.

Again, I don’t eat meat, but the rest of the foods listed above are regular components of my diet. I eat a few ounces of cheese per day, have a couple of eggs most days, and incorporate some quinoa, beans, or a bit of sweet potato for one or two meals per week.

Low Density: Process Foods

Processed food sits at the bottom of the hierarchy. High in sugar, oil, and starch but devoid of essential nutrients, these foods are a disaster for our health and their consumption should be limited as much as possible.

“Processed food” is a nebulous term, so it’s worth elaborating. Food becomes “processed” when its preparation either removes a significant proportion of its essential nutrients OR its preparation significantly increases the bioavailability of its calories. For example, grinding grains into flour, bleaching flour, extracting vegetable oil, and refining vegetable oil all qualify as “processing”. As a result, flour, sugar, oils, and anything made with those ingredients (ex. crackers, chips) are the pre-eminent examples of processed food.

Admittedly, because most heavily processed food is also high in sugar and/or starch, Principle 2 already guides us away from most processed food. However, this rule also advises that we shun refined oils, protein powder, and products such as the Beyond Burger or Impossible Burger.

I generally avoid processed food but I make 2 exceptions in my daily diet. First, I consume protein powder which I require to maintain a high volume of high intensity exercise (I’ve tried eliminating it with poor results). Second, I consume Erythritol which allows me to consume sweet foods while avoiding sugar, which is clearly worse than Erythritol.

How it Works

As with sugar, each nutrients effects on our bodies requires entire books to explain, so I won’t make an attempt here. The simple explanation of why nutritional density works, however, is that essential nutrients are essential to growth, defense, and repair.

Our body is constantly being damaged by our metabolism and environment–that’s what aging is. In the case of metabolism, our body burns carbs/fats for energy which creates byproducts that damage our cells and impair organ function. Likewise, when bacteria or a virus infects our body we need to fend it off and repair the damage. In both cases, essential nutrients are the foundations of these damage control and repair mechanisms, which slow aging and promote well-being

Principle 4: Eat Seafood or Supplement Omega-3’s

A nutritionally dense diet, as discussed in Principle 3, should already incorporate the Omega-3 fatty acids EPA and DHA but they’re so special that they are worth calling out explicitly. Maintaining adequate cellular levels of EPA and DHA reduces cardiovascular disease, cancer, neurodegenerative disease, and more. Amazingly, they are so potent that they are approved as drugs for the treatment of high triglyceride levels!

Unfortunately, only 2% of Americans have adequate EPA and DHA levels which means that most of us need to work to increase ours.

How To Apply

Technically, our body can convert ALA into EPA and DHA but this conversion rate is so low that most people can’t achieve adequate EPA and DHA levels with ALA alone. Unfortunately, many foods with Omega-3’s in them only have ALA (flaxseed, walnuts, etc). As a result, achieving adequate EPA and DHA levels requires either frequent seafood consumption or supplementation.

A seafood-rich diet can be used to achieve adequate EPA and DHA levels but it comes with challenges. The first challenge is eating enough EPA and DHA rich seafood to achieve the appropriate levels (at least a serving per day). Next, some of the most EPA and DHA rich foods are high in heavy metals and frequent consumption of these metals can counteract the benefits of EPA and DHA. Finally, some people don’t eat seafood for ethical reasons.

Fortunately, vegan Omega-3 supplements exist and they solve all these challenges. For starters, supplements make it easy to get enough–just pop some pills before breakfast. Furthermore, because they are extracted from algae (which is where fish get their Omega’s) they are not contaminated with heavy metals and there’s no ethical reason to avoid them.

You can get your EPA and DHA levels tested by purchasing an at-home testing kit from a company like Baze.com (I did and was super deficient before I started supplementing). I personally supplement 1.5 grams of vegan EPA and DHA per day but I also sometimes eat Oysters which are low in heavy metals and, in my opinion, can be eaten ethically.

How it Works

Our cell walls are made up of a layer of fatty acids that our body sources from our diet. When we eat more EPA and DHA our body is able to incorporate more EPA and DHA into our cell walls which affects their flexibility and fluidity. This, in turn, positively affects their function and our health.

Principle 5: Consume the Rest in Moderation

Thus far, these principles have been pretty clear cut. Eat nutrient-dense food that makes you feel good while avoiding sugar, refined starch, and processed food. That’s it, nice and simple.

The obvious question, of course, is what to do about all the foods that don’t fit under the first 4 principles. It’s a question that can only be answered with the following unsatisfying conjecture: it should be safe to consume, in moderation, foods that are not obviously good or bad.

Some of these foods are precisely those that are surrounded by the most controversy. Saturated fat, salt, meat, dairy, and eggs, for example, are constantly debated in the world of nutrition. Some consider them health-foods while others equate their consumption with smoking. In reality, they’re probably both wrong–the existing evidence does not justify either eliminating them from our diet or making them a nutritional pillar.

It is worth briefly discussing each of these foods to get a sense of where the debate stands.

Saturated Fat

Saturated fat was first tied to heart disease by epidemiology studies in the 1950s. Since then, decades of research, costing billions of dollars, has attempted to determine if this correlation is, in fact, causation, or a spurious correlation.

Most people would expect that, if saturated fat is unhealthy enough to warrant limiting its consumption, billions of dollars and decades of research ought to be sufficient to make that determination. Sadly, that does not seem to be the case.

According to a Cochrane Collaboration meta-analysis, increasing saturated fat consumption increases LDL levels and modestly increases heart attacks and strokes. Surprisingly, however, these increases do not show a corresponding increase in deaths–so it’s not clear that those extra heart attacks and strokes indicate excess morbidity, which is what we actually care about.

With that said, the medical establishment still asserts that saturated fat intake should be limited. Ignoring that advice with my level of knowledge would be foolish. As a result, while I suspect current saturated fat guidelines are lower than necessary, I moderate my intake–I’m not drinking coconut oil but I’m also not documenting each gram I consume.

Salt

Salt is another food surrounded by controversy. Salt detractors claim it increases blood pressure and, as high blood pressure causes cardiovascular disease, salt must also cause cardiovascular disease. Proponents, in contrast, claim that the evidence against salt is merely observational and speculative. In other words, it doesn’t meet the bar for limiting its consumption.

It is true that salt increases blood pressure but the question is: does it matter?

4 extra grams of sodium consumption per day increases systolic blood pressure by a rather modest 4mmHG (Americans average 7 grams per day). In the context of optimal systolic pressure (110-120mmHg), a change of 4mmHg is likely inconsequential for the average American with healthy blood pressure. For someone with high blood pressure, however, it may have repercussions.

Epidemiological studies do find a correlation between salt consumption and cardiovascular disease but, for many Americans, processed food is the primary vehicle by which they take in salt. This begs the question, is salt the problem or is it the processed food the salt is eaten with? Unfortunately, a dearth of controlled trials examining salt intake means we do not have a decisive answer to this question.

In conclusion, the hypothesis that salt causes cardiovascular disease is still speculative (with the exception of salt induced hypertension). If your doctor has advised you to limit your salt intake, absolutely follow that advice. For the rest of us, however, it’s probably not worth worrying about.

My blood pressure is normal so I don’t worry much about sodium consumption. With that said, I drink lots of water before eating a salty meal (doing so limits the acute blood pressure increase caused by salt) and I consume a diet high in potassium (which limits the chronic blood pressure increase caused by salt).

Meat

Meat’s critics claim that it causes cancer and that, due to its saturated fat content, it must also cause cardiovascular disease. We discussed saturated fat earlier in this section but it is worth examining the evidence that meat causes cancer.

As with the link between saturated fat and cardiovascular disease, the link between meat and cancer is tenuous. Some epidemiological studies find small correlations between the two but these correlations are weak and they provide the bulk of the evidence. Bolstering this research, however, is an obvious mechanism by which meat might increase cancer.

Meat, being high in protein, stimulates the production of mTOR, a molecule that promotes cellular growth and limits cellular cleanup processes. Cancer, a disease of excess growth, is promoted by excess mTOR. While the meat->mTOR-> cancer link is obvious, it misses an important step in the production of cancer: mutation. Before cancer can take advantage of a high mTOR environment, a cell must first mutate into a cancerous state and evade the immune system–events that can be limited by a healthy lifestyle. In other words, if our lifestyle is otherwise healthy (exercise, not smoking, not obese, etc) it is unlikely that meat consumption significantly impacts our risk of cancer.

Furthermore, large literature reviews tend to find that the risks associated with eating meat are either small or non-existent–that’s for cancer, cardiovascular disease, and all-cause mortality. Directionally, the studies do suggest that excessive meat consumption is unhealthy but the effect size and confidence in that effect are too small to justify limiting meat consumption below normal levels.

Of course, none of this addresses the ethics of meat consumption, which is fraught with issues. I’m a vegetarian as a result, but it’s not for health reasons.

Dairy

Like meat, diary is often demonized for being high in saturated fat and, in the case of cheese, being high in sodium. As was discussed above, the evidence against saturated fat and salt are limited. Furthermore, studies that investigate dairy’s impact on health tend to find a neutral or even slightly protective effect.

This apparent contradiction perfectly demonstrates why studying nutrients in isolation is ill-advised–saturated fat is associated with cardiovascular disease but dairy, which is high in saturated fat, is not.

Once again, I must repeat the caveat that this evidence is largely epidemiological. It’s entirely possible that dairy studies find a protective effect, not because it is healthy, but because people who eat dairy also tend to eat less of something that is unhealthy (soda, for example). The end result is the same as it was for the foods examined previously. When eaten in moderation, dairy appears to have a neutral impact on health.

I personally eat a few ounces of cheese per day and use a bit of butter for cooking eggs.

Eggs

Eggs, high in cholesterol, were first vilified when the link between arterial cholesterol and heart disease was discovered. Surprisingly, however, dietary cholesterol does not significantly impact arterial cholesterol so the initial efforts to curb egg consumption were misguided.

Since then, studies have produced mixed results in their attempt to determine eggs impact on health. Some observational studies show a link between egg consumption and disease but controlled trials, a stronger form of evidence, do not.

Whether eggs are healthy or not, it is not surprising that observational studies find a link between their consumption and disease. Eggs have been vilified as “unhealthy” for years. As a result, someone that eats a lot of eggs is more likely to be a person that doesn’t follow health advice, such as avoiding smoking, which makes them more likely to have disease (but not because of the eggs). Observational studies attempt to control for this effect but they can’t control for everything and the existing results are consistent with insufficient elimination of bias.

In summary, the evidence that eggs are unhealthy is weak and they’re probably fine if consumed in moderation.

I personally eat around 2 eggs per day.

Fruit

Fruit is a bit of an anomaly. On the one hand, fruit is like vegetables–it’s full of essential vitamins, minerals, fiber, and phytonutrients. On the other hand, however, fruit is moderately high to very high in fructose.

Observational studies find that, in the context of the standard American diet, fruit consumption is correlated with positive health outcomes. Unfortunately, however, there is very little research on how fruit impacts an otherwise healthy diet. As a result, we can only speculate.

I currently expect that:

Fruit is a very healthy addition to the average American’s diet because it crowds out very unhealthy foods such as pastries, candy, and soda.
A daily serving or two of low fructose fruit is a healthy addition to an already healthy diet due to the nutritional density of fruit and certain phytonutrients that are found only in fruit.
The benefits of fruit consumption diminish as more fruit is consumed with excessive consumption being a net negative due to large amounts of fructose eventually outweighing the benefits of the other nutrients.
Dried fruit is basically candy, it has all the fructose of fruit with less of the essential nutrients.

Conclusion

Dietary research is a complex, constantly evolving field that is hard to keep up with. This state of constant flux can make it tempting to give up on healthy eating and drive us to simply eat what we please, however, while the landscape is ever-changing, there are some constants from which reasonable dietary principles can be derived. My hope is that you can use these principles, examined in detail above, to form the basis of a frustration-free, healthy diet.