Nutrition 101 – A Guide to Everyday Nutrition

Nutrition 101

“Let food be thy medicine and medicine be thy food” Hippocrates

This guide is recommended to every person who wishes to learn what healthy food is, and maintain optimum health.

Table of Contents

1.  What Is Nutrition?

2.  So, Why do we eat?

3.  What Are Nutrients?

4.  What Happens When We Lack Some of the Nutrients?

5.  What Food Is Our Fuel?

      5.1.  Macronutrients

                5.1.1.  Carbohydrates

                5.1.2.  Fats

                5.1.3.  Proteins

      5.2. Micronutrients

               5.2.1.  Vitamins

               5.2.2.  Minerals

      5.3.  Phytonutrients

6.   Where Can We Find These Nutrients?

7.   What Is Energy Density and What Should You Know about It?

8.   What Is Nutrient Density?

9.   Why Should Everybody Eat Various Food?

10.  What Processed Food Is Bad For You?

      10.1.  What Are The Most Common Misunderstandings About Nutrition?

11.  Why are you having problems with digestive system?

12.  Why fad diets are not good for you?

13.  Why should you be careful with dietary supplements?

14.  How can you determine your calorie intake?

15.  What is food craving?

16.  How can you solve your problem with snacking?

17.  What are 10 secrets of nutrition?

18.  Why food matters?

19.  Why balanced diets need regular exercising?

20.  What are common nutritional myths?


What Is Nutrition?

In short, nutrition is a study of the foods we eat.

The food we eat affects our body, thus affect our health and emotions.

Nutrition has several fields of interest: physical components of digestion, health issues in general, emotional issues related to eating, food science and biochemistry. The main goal of nutrition is to offer us the best possible solutions that will guide us to healthy eating, give us knowledge and understanding about healthy and safe food and the importance of exercising, and promote physical activity.

You need to ask yourself this question: why do you eat? One may say: we eat to live, and yes, we eat because we are hungry, or tired, or emotionally unbalanced, bored, sad, unhappy, or simply because the food smells and looks so good we cannot resist it. All mentioned is true, however, nutrition is beyond this comprehension.

With basic knowledge and understanding of nutrition everyone can learn the ways to improve their life, maintain a healthy eating habits and prevent illnesses. Healthy eating goes hand in hand with understanding the ways our body functions and what our body needs. In this guide we will cover the basics and offer an easy way to improve your life.


So, Why Do We Eat?

We eat because we need the energy from the foods, the energy that will enable our body to function properly and our mind to “operate” effectively. Although we all know this, most of us simply do not develop a healthy eating habits. If consumed properly, the food is our essential fuel. What exactly does the food have that is of immense importance to us?

What Are Nutrients?


What Are Nutrients?

We get individual food components from the food, and these components are nutrients. The digestive system breaks down the food into small and large nutrients and those nutrients are commonly grouped into macronutrients, micronutrients and phytonutrients.

Essential nutrients are those components that our body cannot produce, and they must come from the food. Most vitamins and dietary minerals, and certain amino acids and fats, are essential nutrients.


What Happens When We Lack Some Of The Nutrients?

When we are not getting enough nutrients, or when we are getting too much of a particular nutrient or more nutrients, a condition called malnutrition occurs, and malnutrition is the largest contributor to different diseases across the planet.

Overnutrition is a condition when you take in more nutrients or a nutrient that you need every day (overnutrition is common in countries like United States).

Undernutrition is the form of malnutrition that happens when one does not get enough of a nutrient or nutrients. According to the World Health Organization (WHO), malnutrition is the gravest threat to health globally. It is estimated that around three million people are affected by malnutrition, according to the National Health Service (NHS), UK.

Overnutrition happens when one consumes too much energy that in turn increases weight, and it does not matter if the energy comes from carbohydrates, fats, or protein. When one is overweight or obese, risk factors for cardiovascular disease, and some types of diabetes type 2 and cancers increase. Treating energy overnutrition requires changes and adjustments in diets, in order to reduce calories and regain normal weight. Overnutrition can also happen when one is taking too much micronutrients, usually when one is taking large doses of dietary supplements. This form of malnutrition can cause acute poisoning (iron pills).

Protein-energy undernutrition occurs when one does not consume enough energy. Children in least developed countries suffer from this form of malnutrition. There are also two types of this malnutrition: starvation (sometimes called marasmus) that can result in death, and the other that comes from the lack of protein (called kwashiorkor). PM undernutrition occurs when people do not have enough food to eat or they don’t want to eat.

Undernutrition as a result of vitamin and mineral deficiency occurs when one’s diet is out of balance. The most common mineral deficiencies include iron and calcium deficiency.

The word malnutrition is usually used to refer to energy undernutrition and this type of malnutrition is omnipresent.

This guide will offer you answers to the basic questions of healthy and balanced nutrition, so, one of the first questions we are going to answer is: what should we eat and why?


What Food Is Our Fuel?

We need MACRONUTRIENTS (“macro” means big), and those are Carbohydrates, Fats and Protein. They provide the energy that enables our body to carry out the biochemical reactions throughout the day and night.

CARBOHYDRATES (glucose, fructose and galactose) are the main source of energy for the body, because they create an energy reserve. If we do not get enough glucose (glucose is our body’s favorite energy), our body can make it from protein, and if we have too many carbohydrates, our body will convert them to fat for storage.

FATS (unsaturated, saturated and trans fats) provide energy in between meals; they are essential components of cell membranes and they assist in growth and development of brain function. We need them (polyunsaturated fats – omega-3 fatty acids and omega 6-fatty acids) because our body cannot create them due to the lack of the right enzymes.

PROTEIN is broken down into individual amino acids and our body use these amino acids to create more protein. Essential amino acids, however, must come from the food. Proteins are necessary for building and repairing different parts of the body. Our immune system, hormones, nervous system and organs need amino acids.

We need MICRONUTRIENTS (“micro” means small), that is, vitamins and minerals. There are 12 vitamins and 13 minerals we need every day.

VITAMINS are fat-soluble (A, D, E, K) and water-soluble (B-complex and vitamin C) depending on whether they can dissolve in water or fat. They are necessary because they function as co-enzymes helping our body with chemical reactions.

MINERALS are grouped as major minerals (calcium, phosphorus, chloride, magnesium, potassium and sodium) and trace minerals (chromium, copper, fluoride, iodine, iron, selenium and zinc). Minerals are necessary for many functions in the body.

We need phytonutrients (“Phyto” – refers to plants) although they are not essential for our body. Phytonutrients are chemical compounds that occur in food that also has nutrients, thus, it is sometimes hard to know their health benefits due to the presence of regular nutrients. They are usually found in the skin or the flesh of fruits and vegetables. Some of the best known phytonutrients we have all heard about are carotenoids (beta carotene, lutein, lycopene, and zeaxanthin) and flavonoids (quercetin and anthocyanin). Phytonutrients have different roles and benefits for our health, some of them act like antioxidants and some may help prevent cancer.

We need fiber (a type of carbohydrate that does not provide energy) for our digestive system. There are two types of fiber: soluble that dissolves in water, and insoluble that doesn’t dissolve.

We need antioxidants that are found in phytochemicals in fruits and vegetables, and some vitamins and amino acids. Antioxidants protect our body from damage that comes from the sun, smoke, pollution, and poor diets. They are not required for the body, but they are very helpful and have a powerful impact on the body’s health. Consuming antioxidants, that is food rich in antioxidants, may help lower the risk of infections and some forms of cancer. The best way to increase antioxidants in the organism is by consuming nuts, seeds, legumes, fruits and vegetables.

Antioxidants are also available as dietary supplements, however, the benefits from dietary supplements differ and vary (they show good results in laboratories, but when taken by humans, the results are usually disappointing), and some supplements may be detrimental when taken in large doses (large amounts of vitamin A supplement may cause birth defects when taken by pregnant women, for instance).

NUTRIENTS are necessary providers of the ENERGY (this energy is measured in calories) our body needs, they are necessary for STRUCTURE (organs, bone, teeth, tissues), and they are necessary for BODY’S FUNCTIONS (temperature, metabolism, blood pressure, thyroid function, sweating, and many more functions).


Where Can We Find These Nutrients?

Carbohydrates, as essential body’s energy (most of the calories (45 to 65 percent) should come from carbohydrates), are found in all plant foods such as grains, vegetables, fruits, legumes, nuts, and in milk and milk products.

Fats are found in most of the food we eat every day. Unsaturated fats are in vegetable oils, salad dressings, nuts, seeds, ground flax seeds, avocados and fatty fish, such as salmon, sardines and mackerel. Saturated fats are found in beef and pork, full fat dairy products, snack foods such as cookies, pastries and doughnuts. Trans fats are found in margarines, deep fried food, and snacks such as chips, crackers, pastries and doughnuts.

Proteins are the food of animal origin: meat, fish, poultry, eggs and dairy products.

Vitamins and minerals are found in fruits and vegetables. We will provide you with in detail description of every vitamin and the food that contains a specific vitamin on our website. All you need to know about minerals you will find here.

Fiber is found in whole grains, such as wild rice, brown rice, oatmeal, barley, quinoa, and whole grain products such as wheat bread, cereal and pasta. Fiber is also found in vegetables, fruits and legumes.


What is Energy Density and What Should You Know about It?

The amount of energy that is present in certain weight of food is energy density, and it is represented by the number of calories. There is high energy density food (ice-cream due to the sugar and fat), and low energy density food (spinach for instance). Macronutrients and water determine energy density.

Low density foods are colorful vegetables with high amount of fiber (fiber and water have zero calories). Watery foods are also less energy-dense, and fruits and vegetables are nutrient-dense, meaning that they have a lot of nutrients per serving size (you can read more about nutrient density below).

High energy-dense foods are sweets, French fries, pasta, starchy vegetables, cheese, nuts, seeds and deep-fried foods.

Remember: not all energy-dense food is bad, it is more a question of a portion.

Many diets are based on energy density and weight management. If you keep track of how many calories you take in, in comparison to how many calories you burn, you will probably lose weight more efficiently if you consume less calories and burn more. That is why many diets contain low energy-dense foods, because with low energy-dense food one will feel satisfied with only a fewer calories. On the other hand, if you eat more high energy-dense food, you will need more food to satisfy you, and you will gain weight.


What Is Nutrient Density?

The amount of essential nutrients for the given volume of food is nutrient density. The food that is nutrient-dense, usually have fewer calories (super foods). For instance, carrots and four saltine crackers have about 50 calories, but carrots have many more nutrients for the same number of calories. Which one should you eat? Carrots.

Super foods are nutrient-dense, and we have all heard about super foods. Many fruits and vegetables are super foods (low in calories and high in nutrients). Some of the best nutrients rich foods are carrots, broccoli, kale, spinach, tomatoes, berries, apples, cherries, oranges and pomegranate.

Other food that is rich in beneficial nutrients are salmon, tuna, low-fat dairy products, oatmeal, whole grains, soy, and dry beans.

It is important to choose nutrient-dense super food, and although this food can be more expensive, think why you should choose these foods. Find Nutrient Facts Labels if you are not sure about the nutritional value of certain food.

Remember: peanut butter, dried fruits, cheese and starchy vegetables are both nutrient-dense and energy-dense.

If you need help with finding out the nutritional value of the food, there are some very helpful websites. There is a nutritional value database called National Nutrient Database for Standard Reference maintained by The United States Department of Agriculture. If you want to count your calories, you can visit Calorie Count, where you can track your daily intakes and calculate nutritional value of your diet.

Packaged foods have Nutrient Facts Labels which include information on calories, fats, carbohydrates, vitamins and minerals, and serving size. If you are not sure about the words on the label, you can find all abbreviations used in nutrition in this guide.

AA – Amino Acids

ADEK – Vitamins A, D, E and K sometimes grouped together

AI – Adequate Intake: the amount of a nutrient that meets the requirements of everybody

BMI – Body Mass Index: a measurement that indicates obesity by calculating the relative percentages of fat and muscle in the body

Ca – Calcium: mineral essential for strong bones and teeth, blood clotting, and nerve and muscle function

DRI – Dietary Reference Intake: the levels of nutrients needed for dietary consumption (replaced RDA)

EAR – Estimated Average Requirement: the intake of a nutrient that will meet the requirements of one half of all healthy individuals

Energy RDA – Energy Recommended Dietary Allowance: the average number of calories needed, differing by gender and age

Fe – Iron: a mineral needed for transportation of oxygen throughout the body

FTT – Failure to Thrive: a significant delay in growth of an infant or young child

g – Gram: a metric unit of measure (one ounce is about 29 grams)

IU – International Unit: a measure of the activity of vitamins usually vitamins A, D and E

K – Potassium: a dietary mineral for water balance and healthy muscle function

kcal – Kilocalorie: a measure of energy, “calorie”

mcg – Microgram, a metric unit of measure (1,000 micrograms equal one milligram)

mg – Milligram: a metric unit of measure (1,000 milligrams equal one gram)

Mg – Magnesium: a dietary mineral crucial for healthy muscle function and other processes in the body

mEq – Milliequivalent (equal to one-thousandth of a gram equivalent)

Na – Sodium – a dietary mineral for water balance in the body

RDA – Recommended Dietary Allowance: amount of a nutrient that will meet the requirements of 97.5 percent of healthy individuals

REE – Resting Energy Expenditure: number of calories you would burn if you stayed at rest all day

RNI – Reference Nutrient Intake: used in the UK and stands for the daily nutrient recommendations to meet the needs for the majority of the population

UL – Tolerable Upper Limit: highest level of a nutrient that is safe for all individuals

Care to know how can food labels mislead you? See Top Misleading Food Labels.


Why Should Everybody Eat Various Food?

The common misunderstanding related to food choices is that most of us eat the food for the wrong reasons and chose the wrong food due to the lack of understanding what healthy nutrition is really about.

We choose certain food because it’s tasty (although healthy food is very tasty, somehow most of junk and fast foods that have no nutritional value are tastier for many people). If you dislike the flavor or texture of certain food, you will not eat it, that’s understandable. However, consuming the food only because of its good taste does not mean that the food is healthy (and although many of us know this, we still make the same mistakes).

We also choose the food that is available and easy to find, or the food that is affordable (especially when we are too busy to prepare the food for ourselves).

We also eat socially acceptable food at places that are also socially acceptable.  No one is going to order a salad in a pizza restaurant, right?

Another common mistake is when we eat the food that lacks beneficial nutrients due to emotional reasons. The connection between food and mood can be a serious medical problem. We also eat food due to the cultural background and tradition.

Finally, we eat unhealthy food most of the time when we decide to lose weight.

When we are eating a variety of food we will get all essential nutrients our body needs.

We need to remember that food is not equally beneficial for every person. It may happen that you lack some important nutrients even though you eat the food you think is good for you, or the food that is, in fact, good for you. For instance, let us choose tomatoes. Tomatoes are great because they are a rich source of vitamin C and vitamin B-6, but tomatoes lack protein, and vitamin B-12. So if you need protein and vitamin B-12, eat tomatoes with chicken. Just like tomatoes and chicken balance the nutrients you need, other food can balance it as well, thus, you need to be more familiar with food combining.

Food is usually grouped in the following categories:

Fruits and vegetables

Dairy products and food rich in calcium

Grains and cereals

Meat and protein food

Fats and oils

These foods contain beneficial nutrients, and if combined in the proper way, you will be able to balance your diet.

If you need some help, there is a good way to sort out the various food groups and determine the quantity and quality of the food you need to create a healthy meal using You can create your balance diets according to your weight and physical activity. On the other hand, I do suggest learning and educating yourself more about nutrition and food in particular, and create your own balance diets without any programs (although they can be very helpful at the beginning).

One more reason why every person should be familiar with the nutritional value of the food is because it is the easiest way to balance the consumption of healthy food with the food that lacks any benefits and value, and the truth is that we all eat less nutritious food.

For more info on the healthiest food we should eat every day, read this article.


What Processed Food Is Bad For You?

Processed food is altered food, usually for safety reasons. Processing methods are canning, refrigeration, dehydration, aseptic processing and freezing, and although many think that processed food is all bad, there are also good processed food we eat every day (milk, certain breakfast cereals, freezing vegetables, fruit juices, canned salmon, frozen berries, and more).

However, processed food made with trans-fats, saturated fats and large amounts of sugar and sodium is very bad for your health (see why sugar can be really bad for your health).

The food that you should avoid is the following:

Processed meats (hot dogs, bologna, sausage, ham and other packaged lunch meats)

Packaged cookies and cakes

Frozen dinners high in sodium

Canned foods with large amounts of fat or sodium

Pasta made with refined white flour

Candies and chips

These foods can increase the risk of high blood pressure, cholesterol, heart diseases, kidney and stomach cancer. Read more about Top 7 Worst Foods in the World.

What Are The Most Common Misunderstandings About Nutrition?

Now we have come to the part of the guide where we are going to answer some frequently asked questions about nutrition that can be both misleading and wrongly interpreted. Here is what you need to know.


Why are you having problems with digestive system?

One of the reasons why most of people can have problems with digestion is due to the lack of fiber. The recommended intake of fiber is 20-35 grams for healthy adults (for 2,000 calories a day, you need 25 grams a day, and 30 grams if you eat 2,500 calories a day), and most of us are not meeting this recommended intake. We need fiber because:

It lowers blood cholesterol

It prevents constipation

It normalizes blood glucose and insulin levels

It reduces the risk of colorectal cancer and breast cancer

Your diet should include foods rich in fiber (fresh, frozen, raw or cooked fruits and vegetables, especially the vegetables that are dark green or brightly colored).

Remember: refined foods, such as pasta or white bread, have no fiber; it is lost due to the refining process.


Why fad diets are not good for you?

With fad diets you can lose some weight at the beginning, but you will regain it after you stop dieting. There are several problems with fad diets:

Deprivation of essential nutrients

Restriction of carbohydrates (usually) or other food groups

Dehydration, weakness and fatigue

Problems with digestive system (constipation)

Nausea and headaches

Do not include adequate mineral and vitamin intake


Why should you be careful with dietary supplements?

Dietary supplements can cause problems if taken in large doses (iron, vitamin A and vitamin B-6). Other problem is that they are not always standardized or regulated. Before you take any supplement, consult with your health provider.


How can you determine your calorie intake?

To calculate your calories you need to know your current height and weight, and your activity level on a daily base. You can use The Harris-Benedict formula, but be careful because researchers indicate that the formula is not always adequate (90 percent of accuracy around 60 percent of time). There are also online calculators for both men and women.


What is food craving?

When you are craving for certain food it is a way for your body to tell you that something has changed, and that there might be a problem, usually there is a mineral and vitamin deficiency in your body. All you need to know about food cravings you can find within these 19 reasons for food cravings.


How can you solve your problem with snacking?

Snacking is a habit, but, it is also a consequence of irresponsible dieting, a result of the emotional stress, or stress in general, and a lack of information on nutrition related to the body’s functions. Many people can gain weight very fast as a result of snacking. If you are having problems with snacking, see the list of 30 things you can do instead of eating snacks. On the other hand, there are 35 snacks you can eat guilt-free.


What are 10 secrets of nutrition?

We all know the things we shouldn’t do, but somehow we are still doing them, and we are still making the same mistakes, such as, eating when in fact we are thirsty, eating in front of TV, and not eating enough vegetables and fruits, and more. Read more about 10 nutritional secrets here.


Why food matters?

It matters because it can help us improve our body’s health, and make our organism function properly. Apart from the fact that we need the energy from the food, due to the beneficial nutrients, we need food to protect our eyes and liver, for instance, to improve our mood and emotional state, to enhance our brain’s function (concentration, alertness, cognition), to protect ourselves from cold and infections, to protect our skin, to control our blood pressure, and much more.


Why balanced diets need regular exercising?

If you want to enjoy a healthy and happy life you need to understand the word balance. Food is our energy, and balanced nutrition is what makes us capable to perform at our best, however, that energy we consume through food needs to be released and transformed. Any form of physical activity helps us release the energy, which in turn makes our body even stronger and healthier. For optimum health we need to consume and release the energy. Due to regular exercising, our immune system becomes stronger, our nervous system becomes efficient, our emotions are balanced, we decrease stress and anxiety (these two are the main culprits for an unhealthy lifestyle).


What are common nutritional myths?

We often get confused about the food we should eat, or shouldn’t. We question whether or not we should eat protein and how much. We sometimes do not know why carbohydrates are good for us. Read the answers to these and other questions in this article.
What is food?

Isn’t this a strange question? Yes, it is, however, we need to be reminded that the food is our energy. On the other hand, given that this is the last question we’ll answer in this guide, we need to emphasize that the food cannot give us a miraculous wand for our health problems. We need to change the way we think about life, and we need to be responsible toward our body. The food we eat, the energy we receive, is only one piece in the puzzle.


Further readings on nutrition:

Pocket Supermarket Guide, 4th Edition by Mary Abbott Hess, MS, RD, LHD, LDN, FADA. Academy of Nutrition and Dietetics, 2014.

The 5 Hungers: Stealth Appetites You Can Satisfy Without Overeating by Beverly Hyatt Neville, PhD, RD. Let Me Read It, 2012.

Food, Field to Fork: How to Grow Sustainably, Shop Wisely, Cook Nutritiously, and Eat Deliciously by Anita M. Kobuszewski, MS, RD. AnitaBeHealthy Publishing, 2012.

Nutrition Concepts and Controversies by Frances Sienkiewicz Sizer, MS, RD, FADA and Eleanor Noss Whitney, PhD. Wadsworth, Cengage Learning, 2014.

American Dietetic Association Complete Food and Nutrition Guide, 4th Edition by Roberta Larson Duyff, MS, RD, FADA, CFCS. Wiley, 2012.

Sugar Nation: The Hidden Truth behind America’s Deadliest Habit and the Simple Way to Beat It Hardcover by Jeff O’Connell. Hyperion, 2011.

Good Calories, Bad Calories: Fats, Carbs, and the Controversial Science of Diet and Health by Gary Taubes. Anchor, 2008.

Starting Strength by Mark Rippetoe and Jason Kelly. The Aasgaard Company, 2011.

Healing with Whole Foods: Asian Traditions and Modern Nutrition by Paul Pitchford. North Atlantic Books, 2003.

Yoga Cures: Simple Routines to Conquer More Than 50 Common Ailments and Live Pain-Free by Tara Stiles. Harmony, 2012.

Advanced Nutrition and Human Metabolism by Sareen S. Gropper, Jack L. Smith. Cengage Learning, 2008.

What to Eat by Marion Nestle. North Point Press, 2007.

Appetite for Profit: How the food industry undermines our health and how to fight back by Michele Simon. Nation Books, 2006.

Food Matters: A Guide to Conscious Eating with More Than 75 Recipes by Mark Bittman. Simon & Schuster, 2009.

“Amino Acids.” United States National Library of Medicine National Institutes of Health, Medline Plus.

“Dietary Supplements.” National Institutes of Health, Office of Dietary Supplements

“Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein and Amino Acids.” Institute of Medicine of the National Academies. September 05, 2002.
Drewnowski A. “Concept of a nutritious food: toward a nutrient density score.” Am J Clin Nutr. 2005 Oct; 82(4):721-32.

Insel, P. and a group of authors (2010). “Nutrition”. Jones & Bartlett Learning.

“Fats Resource Center.” Harvard Medical School, Harvard Publications.

Gropper SS, Smith JL, Groff JL. “Advanced Nutrition and Human Metabolism.” Fourth Edition. Belmont, CA. Wadsworth Pub Co. 2005.

“Health Implications of Dietary Fiber.” Academy of Nutrition and Dietetics.

“Know Your Fats.” American Heart Association.

“Minerals.” United States National Library of Medicine National Institutes of Health, Medline Plus.

Sizer, F., Whitney, E. (2013). “Nutrition: Concepts and Controversies”. Cengage Learning.

Smolin LA, Grosvenor, MB. “Nutrition: Science and Applications.” Third Edition. Wiley Publishing Company, 2013.

“Vitamins.” United States National Library of Medicine National Institutes of Health, Medline Plus.

Willett, W.C. (2005). Eat, Drink, and Be Healthy: The Harvard Medical School Guide to Healthy Eating. Free Press.

“What Is an Antioxidant?” Academy of Nutrition and Dietetics.

Whitney, E.N., Rolfes, S.R. (2012). Understanding Nutrition. Cengage Learning.

Images credit: 123RF Stock Photo

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