Nutrition for Beginners

The Most Important Thing to Learn Is What Not to Eat

A shortcut to understanding food, chemistry, cravings, and the human body

If you’re a newcomer to the science of nutrition, I have a few shortcuts that can give you a surprisingly sophisticated understanding of the subject without requiring you to spend the next four years studying biochemistry.

When people begin learning about nutrition, they tend to get lost in chemistry. We study proteins and how they break down into amino acids. We study carbohydrates, fats, vitamins, minerals, enzymes, and hormones. We study digestion, metabolism, and the mechanisms by which different compounds enter our bloodstream and become part of our bodies.

All of that information is useful. Some of it is fascinating. But I believe there is a much more important place to begin.

Before you learn what to eat, learn what not to eat.

That might sound like an odd way to teach nutrition, but imagine that we were living thousands of years ago, wandering through a forest with a group of teenage boys, teaching them how to find food.

I might begin the lesson by pointing to a particular bush and saying, “Guys, don’t eat those berries. And stay away from that mushroom over there. That one can kill you.”

It would be a pretty intelligent place to begin. After all, if somebody eats the wrong mushroom and dies, the rest of the nutrition lesson becomes somewhat irrelevant.

The principle hasn’t changed. The dangers have changed.

Today, most of us aren’t wandering through forests looking for poisonous berries. We’re wandering through supermarkets looking at brightly colored boxes, packages, bottles, and bags, trying to determine what’s food and what is essentially an industrial formulation designed to resemble food.

And this brings us to my first rule of nutrition.

1. Learn to Recognize Ultra-Processed Food

When I say processed and refined foods, you probably imagine candy, packaged cakes, artificially flavored drinks, and the enormous selection of colorful products lining the shelves of convenience stores.

You’re on the right track.

These foods may contain combinations of refined sugars, refined starches, extracted fats, flavorings, colors, emulsifiers, stabilizers, and other ingredients used to create particular textures, appearances, tastes, and shelf lives.

Food scientists can make something chewier, crunchier, creamier, sweeter, or more resistant to melting. They can make products remain appealing for months and sometimes years.

Not every one of these ingredients is inherently dangerous. That distinction matters. But the overall nutritional quality of many ultra-processed products is poor, and their convenience and intense palatability can encourage excessive consumption.

This is where some of the problems begin.

Many of these products are engineered to be extremely appealing. They’re convenient, highly accessible, heavily advertised, and often inexpensive relative to more nutritious alternatives.

And they are everywhere.

Soft drinks, sweetened energy drinks, bottled coffees, candy, desserts, packaged snacks, and many ready-to-eat meals are obvious examples.

But we also need to be more observant. The supermarket contains thousands of foods that look wholesome because of the language and artwork on their packaging. Words like natural, healthy, energy, protein, and organic can create a reassuring impression without telling us enough about the food’s actual nutritional value.

A product doesn’t become healthy simply because a manufacturer prints a picture of a farm on the package.

However, we should also understand that processing isn’t automatically harmful. Washing, chopping, cooking, freezing, fermenting, and canning are forms of processing. Frozen vegetables, cooked beans, tofu, and plain oats can all be valuable parts of a healthy diet.

The real issue is what processing has removed, concentrated, added, or changed, and how that affects what we ultimately consume.

2. Understand the Difference Between a Fruit and Refined Sugar

Here’s another shortcut that can save you an enormous amount of confusion.

Sugar has acquired a terrible reputation, and carbohydrates have been dragged into the argument along with it.

As a result, some people have become afraid of bananas, potatoes, grapes, and other perfectly nutritious plant foods.

That’s a mistake.

Consider the difference between eating an orange and consuming a sugary soft drink.

Both may contain sugar molecules that the body can use for energy. The molecules themselves aren’t magically different because one came from nature and the other from a factory.

The difference lies in the entire food.

An orange contains water, fiber, vitamins, minerals, and numerous plant compounds. Its physical structure influences how quickly we eat it, how full we feel, and how its nutrients are absorbed.

A soft drink containing added sugar provides concentrated energy with little nutritional value beyond those calories.

In other words, the nutritional value of food cannot be determined by examining one isolated molecule.

We must consider the entire package that nature provides.

This is particularly important when discussing refined starches and sugars.

White flour, for example, has had important components of the original grain removed. Refining sugar separates it from the plant material that originally surrounded it.

The result is a concentrated ingredient that can be added to almost anything.

When you combine refined sugars and starches with fats, salt, and carefully chosen flavors, you can create foods that are extraordinarily easy to overconsume.

The problem isn’t that the body is incapable of handling sugar. It handles sugar continuously, and the hormone insulin helps regulate blood glucose and its use and storage.

The problem develops when our overall eating patterns repeatedly overwhelm our energy needs, displace nutritious foods, and contribute over time to metabolic dysfunction.

This helps explain why diets consistently high in added sugars, particularly from sweetened beverages, are associated with weight gain and poorer metabolic health.

It also explains why telling somebody to avoid fruit because it contains sugar misses an important part of the science.

Whole fruit and sugary soda aren’t nutritional equivalents.

And neither are a baked potato and a doughnut.

3. Food Doesn’t Just Affect Your Weight

Here’s where nutrition becomes especially interesting to me.

We often discuss food as though its only purpose is to determine how much we weigh, how muscular we become, or whether our cholesterol is too high.

But the body is an interconnected biological system.

What we eat influences blood glucose regulation, digestion, energy availability, cardiovascular health, and numerous processes involving hormones and the immune system.

Over time, a poor dietary pattern can contribute to insulin resistance, type 2 diabetes, cardiovascular disease, and other chronic conditions.

Inflammation is another important part of the conversation.

Chronic low-grade inflammation is associated with several metabolic diseases. Certain dietary patterns appear to promote inflammatory conditions, while others, particularly those rich in fiber and nutritious plant foods, are generally associated with better metabolic health.

But we should be careful not to claim that every ingredient causes inflammation or that every unpleasant bodily sensation can be traced to one particular food.

Biology is complicated.

Which brings me to something that is discussed far too little in conversations about nutrition.

What is the relationship between what we eat and how we experience our own thoughts and emotions?

4. Nutrition and the Anxious Mind

I’ve spent much of my life studying anxiety, observing my own nervous system, and trying to understand the relationship between our chemistry and our conscious experience.

We know that anxiety is influenced by many things.

Our childhood experiences, relationships, genetics, sleep, psychological conditioning, environment, and present circumstances can all contribute to how our nervous systems respond.

But we are also biological organisms.

Our brains require energy. Our bodies respond to changes in blood glucose. Hunger, inadequate nutrition, excessive caffeine, sleep disruption, and certain metabolic conditions can influence how we feel.

Sometimes the sensations of low blood sugar, including shakiness, sweating, or a racing heart, can resemble symptoms of anxiety.

And sometimes our relationship with food becomes psychological.

We feel stress, so we eat. We feel tired, so we reach for sugar or caffeine. We experience discomfort, so we look for something pleasurable that can provide immediate relief.

Food becomes more than nourishment. It becomes a method of emotional regulation.

Research has found associations between greater consumption of ultra-processed foods and poorer mental health outcomes, including depressive and anxiety symptoms. That doesn’t establish that those foods directly cause anxiety in every individual, but it is a relationship worthy of further investigation.

We also need to recognize that the relationship can work in both directions. People experiencing psychological distress may be more likely to rely on convenient, highly palatable foods.

This creates a potentially difficult cycle.

A person might experience stress, eat poorly, sleep badly, feel physically uncomfortable, and then become increasingly sensitive to the very stress that influenced their eating in the first place.

Nutrition is not a substitute for therapy, medication when necessary, or the deeper psychological work required to understand our emotions.

But it can be an important part of creating the physiological conditions in which we feel better.

For me, that’s an essential connection.

We cannot completely separate the condition of the body from the condition of the mind.

5. Why Do We Crave Things That Aren’t Good for Us?

Now we arrive at one of my favorite questions.

If we know that certain foods aren’t particularly good for us, why do we keep eating them?

Why does somebody reach for the same candy, the same cookies, or the same sugary drink, even after deciding a hundred times that they’re going to stop?

Part of the answer involves the brain’s reward system.

Pleasurable experiences engage neural circuits involving dopamine and other signaling chemicals. These systems help us learn what is rewarding and motivate us to repeat certain behaviors.

Food is naturally rewarding. It has to be. Our ancestors needed motivation to find nourishment.

But modern food manufacturers have become extraordinarily skilled at combining sweetness, fat, salt, texture, and convenience in ways that make certain products difficult to resist.

Some people describe their relationship with highly palatable foods in terms of addiction.

There is scientific debate about whether sugar itself produces addiction comparable to substances such as tobacco, alcohol, or opioids. The evidence doesn’t justify treating these as chemically equivalent.

Still, compulsive patterns of eating and powerful cravings are real experiences.

And when those cravings interact with emotional distress, habits, environmental cues, and a constant supply of tempting products, the behavior can become remarkably persistent.

Consider how often we use food to change our emotional state.

We celebrate with it. We comfort ourselves with it. We reward ourselves with it. We use it to relieve boredom, loneliness, frustration, and anxiety.

The food itself is only part of the story.

The other part is the relationship we’ve developed with the experience of eating it.

This is where nutrition begins to overlap with psychology, behavioral conditioning, and the development of self-awareness.

And it explains why knowing what to eat doesn’t always result in eating it.

6. The Food Industry Didn’t Create Human Cravings. It Learned How to Sell to Them.

I don’t believe that we can have a complete discussion about modern nutrition without discussing the food industry.

The commercial food business has become enormously sophisticated.

Corporations employ food scientists, marketers, packaging specialists, consumer psychologists, and advertising agencies to make their products more appealing and commercially successful.

Some companies sell genuinely nutritious products. Others make enormous profits from products that contribute little to a healthy diet.

The conflict is obvious.

A company’s commercial success is generally measured by sales and profitability, not by whether its customers become healthier over the next twenty years.

This creates an incentive to make products desirable, inexpensive to manufacture, easy to distribute, and attractive enough to encourage repeat purchases.

The result is an environment in which people are surrounded by foods that can be consumed almost effortlessly.

For many products, you don’t have to prepare anything, wash anything, peel anything, or even sit down.

Just open the package.

Food has become entertainment, convenience, pleasure, and sometimes emotional anesthesia.

And while personal responsibility matters, we shouldn’t ignore the enormous influence of the environment in which people are making their choices.

I find it particularly strange that our culture sometimes treats abstinence from unhealthy products as though it’s an unreasonable sacrifice.

We abstain from countless things as a normal part of adult life.

We don’t eat everything we see. We don’t drink every liquid we’re offered. We don’t engage every impulse.

Discipline is not necessarily deprivation.

Sometimes discipline is simply understanding what contributes to our well-being and deciding that we prefer the benefits of abstinence to the immediate pleasure of consumption.

That doesn’t require perfection. It requires awareness and practice.

7. What Did Our Ancestors Eat?

Let’s return to our imaginary forest.

Thousands of years ago, human beings were living in remarkably different environments.

Some populations inhabited fertile areas rich with fruits, roots, seeds, nuts, and other edible plants.

Others lived in colder regions where plant foods were scarce during parts of the year and animal foods played a larger role.

Human diets varied considerably according to geography, climate, season, available resources, and cultural knowledge.

There was no single prehistoric diet that every population followed.

Our ancestors gathered plants, hunted animals, fished, collected shellfish, ate insects in some cultures, and developed increasingly sophisticated methods of finding and preparing food.

They were resourceful and adaptable.

And they had to know what was safe to eat.

A poisonous plant could kill them. Spoiled meat could make them sick. Inadequate nutrition could leave them weak and vulnerable.

The knowledge required to survive was practical.

They didn’t need to understand the molecular structure of vitamin C to recognize that particular foods helped sustain them.

Their knowledge was accumulated through observation, experience, teaching, and survival.

Of course, we shouldn’t romanticize ancient life. Our ancestors faced infectious diseases, food shortages, parasites, injuries, and numerous other dangers.

But one thing they did not face was a supermarket containing thousands of industrially formulated products marketed through modern advertising.

So what changed?

We developed agriculture, food preservation, manufacturing, industrial processing, global transportation, refrigeration, and increasingly elaborate systems of mass production.

Many of those developments were extraordinary achievements.

Food became more available, safer in many respects, and easier to store and transport.

But the same technologies that made modern civilization possible also allowed us to produce enormous quantities of highly refined foods.

We learned how to isolate sweetness, concentrate fats, manufacture textures, and create products that could remain on shelves for extraordinary lengths of time.

And we learned how to sell them.

The problem wasn’t the discovery of food technology itself.

The problem was that convenience, profitability, and pleasure sometimes became more important than nourishment.

8. The Simplest Nutrition Lesson I Can Give You

If you’re just beginning to study nutrition, you don’t need to memorize every vitamin, every amino acid, or every chemical reaction before making meaningful improvements to your diet.

Start with a few basic principles.

Eat a wide variety of nutritious foods, especially vegetables, fruits, beans, lentils, whole grains, nuts, and seeds.

Understand the difference between whole foods and heavily refined products.

Pay attention to added sugars, excess sodium, the types of fat you consume, fiber, and overall nutritional quality.

Learn to read ingredient lists, but don’t assume that a long ingredient list automatically means something is dangerous.

If you follow a completely plant-based diet, make sure you’re meeting your requirements for essential nutrients, including vitamin B12.

And, perhaps most importantly, begin observing how your eating patterns affect your energy, digestion, appetite, sleep, and emotional experience.

Do you feel satisfied after a meal?

Do you experience persistent cravings?

Are you reaching for food because you’re hungry, or because something in your emotional life is uncomfortable?

Can you distinguish between a genuine physical need and a conditioned habit?

Those questions are not a replacement for nutritional science. They are a practical way to apply some of that science to everyday life.

And remember that healthy eating doesn’t require living in fear of every ingredient.

We should be informed without becoming obsessive.

We should be disciplined without becoming rigid.

We should be curious without accepting every alarming claim we encounter.

9. Nutrition Is Also a Practice of Consciousness

I’ve come to believe that many of the most important changes we make in life begin with observation.

We notice a pattern. We recognize its consequences. We begin to understand how the pattern developed. And then, slowly, we learn to interrupt it.

Food is no different.

Maybe you discover that certain meals leave you feeling energetic and comfortable, while others leave you sluggish.

Maybe you realize that you’re consuming sugary foods every afternoon, not because you’re hungry, but because you’re exhausted or anxious.

Maybe you notice that when you’re emotionally distressed, your ability to make thoughtful decisions about food becomes weaker.

Now you have something useful.

You have awareness.

And from awareness, you can begin making different choices.

You can learn to pause before acting on a craving. You can make nutritious foods more accessible. You can develop a more consistent eating routine. You can practice tolerating mild discomfort without automatically trying to eliminate it through food.

None of this requires a chemistry degree.

It requires patience, curiosity, and the willingness to change habits.

I don’t believe that eating well guarantees happiness, prevents every disease, or eliminates the need for psychological work.

But I do believe that taking care of our bodies creates a better foundation from which to face life’s challenges.

Nutrition is one part of that foundation.

Sleep is another. Movement is another. Relationships, relaxation, and emotional honesty are others.

And the beauty is that we can begin at any moment.

We don’t have to understand every molecule in the universe before making a thoughtful decision about what to eat for lunch.

We can start with a much simpler question.

Does this food genuinely nourish me, or am I eating it primarily because somebody figured out how to make me want it?

That’s not the whole science of nutrition.

But it’s an excellent place to begin.