What kind of diet to follow?


How can we know what kind of diet to follow? That is the question, isn’t it? In a time where there is virtually endless information at the tips of our fingers (social media, celebrity endorsements, specialty sites, research papers, all of which is accessible to everyone with an internet connection), it’s even harder to sort out the truth from the hype. Not only are there different sources of information, we are all different people with unique bodies. Thankfully, the scientific method and scientific research allow us a fundamental understanding of some patterns. Here’s some of what we know:

Diet Basics

In the most basic sense, our body composition is generally a result of one equation: calories IN versus calories OUT: Calories consumed versus calories burned. If you consume more calories than your body uses, you will gain weight. If you use more calories than you consume, you will lose weight. Most of our bodies have the ability to regulate and maintain our weight if our food consumption and activity level stay consistent. (2) Genetics and health also play a role in how your body stores and processes what you consume. (1)

So… what makes up the calories you burn? Every day, you have a Total Energy Expenditure (TEE), which accounts for how much energy your body uses in that day. TEE is made up of three main components:

  • Resting Metabolic Rate (RMR): The minimal energy required to sustain vital bodily functions such as blood circulation, breathing, maintaining a good body temperature, etc. For an average person, RMR accounts for 70% of your TEE.
  • Thermic Effect of Food (TEF): The amount of energy expended beyond the RMR as a result of the digestion, storage, and use of food. For an average person, TEF accounts for 6-10% of your TEE.
  • Energy Expended from Physical Activity: The energy expended by moving. Exercise is included here, but this goes beyond your intentional workout. This refers to walking, typing, wiggling your toes, taking the stairs, dancing to your favorite song, keeping your torso upright, hauling your groceries inside from your car, etc. For an average person, this will account for around 20% of your TEE.

Alright, now that we know what makes up the calories we burn… what makes up the calories we consume? What even is a calorie? In nutrition terms, a calorie is defined as “the amount of heat needed to raise the temperature of 1 kilogram of water from 0 to 1 degrees Celsius”. If that’s confusing to you, just think of a calorie as a unit of energy. For our body to use and expend energy (aka burn calories), it needs energy added to the system. That’s what eating does– it provides that energy.

There are a lot of factors that play into how much energy you need. Nobody is exactly the same, and factors such as activity level, pre-existing health conditions, gender, BMI, genetics, and hormone balance play into your energy needs. This handy chart can help you estimate your caloric needs (10). Please seek out a professional in the medical, fitness, or nutritional field if you want to make drastic changes to your weight or diet, or have questions or concerns.

We consume calories in the form of macronutrients. Carbs, fat, and protein. These different sources provide calories at different rates. Carbohydrates provide 4 calories per gram; fat provides 9 calories per gram; and protein provides 4 calories per gram. (Fun fact: Pure alcohol provides 7 calories per gram!) A food rarely only contains one of the three macronutrients. Most foods are a combination of all three! Milk is a great example, explained well in this graphic below from Andy Brunning:

what kind of diet to follow

Let’s take a more in-depth look at the three macronutrients.


When you hear “carbs”, what foods do you think of? Really, stop and think of an answer. Most of us probably conjure up images of warm bread rolls and oodles of noodles. Those do have a lot of carbs. What else has a significant amount of carbs? Fruits. Beans. Chocolate cake. Whole grain bread. Zucchini. Gatorade. Potatoes. Honey buns. You might look at the graphic above and say, “This graphic doesn’t say ‘carb’ on it anywhere!” But it does say “lactose”. Lactose is a sugar, and sugar is a carbohydrate.

Clearly, carbohydrates come in a variety of palatable forms. Is a carb a carb a carb? No. We can actually sort carbs into three categories: sugar, starch, and fiber.

In nutrition terms, a sugar is an organic compound that makes up our food, like the lactose in milk. The flesh and juices of apples, potatoes, zucchini, beans, and bread are made up of sugars as well as proteins and fats. If you’ve ever looked at nutrition facts for fruit or unsweetened fruit juice, it will have grams of carbs while having no ingredients other than the fruit itself. Take a look at my orange juice:

what kind of diet to follow

Ingredients: Orange Juice. Total Carbohydrates: 26g. Total Sugars 22g. Includes 0g of added sugar.

Now, take a look at oatmeal:

what kind of diet to follow

The whole graphic is great, but what I want you to see are those chains on the right-hand side. See where it says “amylose” and “amylopectin”? Below that, you can see that those chains are made up of glucose molecules. Oh, and notice the words starch and fiber that I mentioned earlier! 

To give you some further clarification, we have simple and complex carbohydrates. Simple carbohydrates are the building blocks- food legos- the smallest pieces. White granulated table sugar is a simple carbohydrate. Glucose is a simple carbohydrate that makes up the chains of amylose that we looked at in the oatmeal graphic. Simple carbohydrates provide energy to our body, but not much else.

Those chains of amylose and amylopectin are complex carbohydrates: a big tower made out of the lego blocks. Your body then has to break that down back into the individual lego blocks to be able to use those blocks in other ways and places, like fueling your movements! That’s actually where the TEF comes from. Your body takes what you eat and uses energy to break it apart, so it can utilize those food legos for other things. Not only do carbs provide quick energy to muscles that help you feel energized, your central nervous system (brain and spinal cord) run exclusively on glucose, a simple carb! You need carbs! 

Lastly, the difference between starch and fiber is that our digestive system has the ability (aka the correct enzymes) to break down starch, but not fiber. Starches are broken down into the legos and used as energy! Fiber cannot be broken down by our digestive systems, but that is in fact what makes their role in our diet vital. Fiber pushes the contents of your digestive tract (aka the food you’ve eaten) through the entire tract, which means it helps you poop. And we all poop. Everybody has to poop. If you’re often constipated or having hard nuggety poops, eat more fiber! Fun fact, what is considered fiber can differ between species. For example, we humans cannot digest cellulose, and it is fiber for us. But cows and goats have the correct gut enzymes to successfully break down cellulose, so for a cow’s diet, cellulose is considered a starch and not a fiber. 

Summary / TLDR – The macronutrient carbohydrate provides us 4 calories per gram that we need for the cells in our body to have the energy to function. Our Central Nervous System runs exclusively on carbohydrates! There are simple carbohydrates: the smallest building blocks of sugar that the body can utilize. There are also complex carbohydrates: starch and fiber, chains made up of those simple carb building blocks. The body gets energy from the sugar building blocks and must use energy to break down complex carbs into the smaller building blocks. Starches are complex carbs that we humans can digest / break down into simple sugars. Fiber are complex carbs that we are unable to digest, therefore they play the vital role of moving food along our digestive tract and then getting pooped out.


Stop, close your eyes, and paint a mental image of what you think of when you hear the dietary term “fats”. You probably imagined butter and fat trimmings off of a steak or chicken. Perhaps you also thought about oils we use to cook with. Those are all great and correct answers of dietary fat! Add to that list fish, fried potatoes, milk, nuts, avocados, pizza, chocolate cake, peanut butter, and seeds.

So, is a fat a fat a fat? Same answer as before… no! The composition and variety of fats is a little more complicated than carbs, so here is a nice graphic from the same talented Andy to give you a basic idea:

what kind of diet to follow

There are lots of types of fat. But what does our body use fat for, besides filling up areas we’d rather they didn’t fill up? 

Fat is primarily energy storage for later. Dietary fat is stored in adipose tissue. Then, when you are in need of energy and all your carbs have been burned through, your body will begin to burn fat as energy. But that’s not all that fat does. Fat is necessary to transport substances around your body! Vitamins A, D, E, and K can only be absorbed and used by the body through the use of fat molecules. Check out the graphic by Andy below for a more in depth exploration of vitamins:

what kind of diet to follow

Fat plays roles in hormones, temperature regulation, blood clotting, brain development, and more… all of which are vital and necessary to a healthy person!

I’m sure you’ve heard the word “cholesterol” before. Did you know there is more than one type of cholesterol? Peep the graphic about fats once again. There’s high-density lipoprotein (HDL), low-density lipoprotein (LDL) even very low-density lipoprotein (VLDL)… LDL raises your risk for heart disease and stroke, whereas HDL can lower your risk (6). 

Fats come in many forms. Some help move necessary molecules, some clog our arteries. Distinguishing between healthy fats and unhealthy fats is a great skill to build. In general, we should aim to limit foods that are high in saturated fats and avoid trans fats. Saturated fats are solid at room temperature and found in natural sources such as meat and poultry, cheese, dairy, and coconut oil. Trans fats are artificially hydrogenated fats and are often used to increase the shelf life of items. They are found in ‘convenient foods’ like frozen ready-to-eat entrees, baked goods, and fast food fryers. There is so much evidence of the negative effects of consumption of trans fats that the FDA no longer considers partially hydrogenated oils safe (7).

Instead, aim for most of your dietary fat to come from mono- and polyunsaturated fats. Omega-3 and -6 fatty acids are in this category! These come from a variety of natural sources such as avocados, fish, nuts, seeds (like sunflower, chia, and flax), unsweetened nut butter, and olive, corn, or grapeseed oil to name a few. When isolated, these fats tend to be liquid at room temperature.

One study showed that if you put people on a controlled diet of differing fatty acid compositions, after about six months, their adipose tissue fatty acid composition reflected the new dietary fatty acid composition (5). I guess you are what you eat after all. Your body is being built by the building blocks you put in it! So it’s important that we put in a variety of helpful blocks. Speaking of building blocks… let’s look into what makes up the majority of our structure.


Summary /  TLDR – Fat is a macronutrient that gives us 9 calories per gram and that plays vital roles in our bodies’ functionality. There are many forms of fat; some are healthy and necessary in proper doses, and some can be harmful. Generally, we should aim to limit saturated fat from meat and dairy and avoid convenience foods that are high in trans fat like prepackaged foods and fast foods. We should aim to consume our fat calories from healthy and natural sources such as avocados, nuts, seeds, oils, and fish.


What food do you think of when I say protein? Probably meat, poultry, fish, eggs, nut butter, beans, maybe even protein shakes or bars! 

Are proteins broken down into smaller blocks, like the other macronutrients we’ve discussed? Yes! Proteins– all different kinds– are built from just 21 amino acids. Think about the alphabet. Letters are combined to make words. Those words can be chained together and turned into sentences; sentences into paragraphs; paragraphs into chapters; chapters into books; and books into series! You get the point. Following this analogy, letters of the alphabet are amino acids; words are proteins; sentences are myofibrils; paragraphs are muscle fibers; chapters are muscles; books are muscular systems; and you as a whole are the series! Proteins make up much more than just muscles- they provide structure to hair, nails, bones, skin, blood, and more. Most of these amino acids can be created by the body using the food we give it, but there are 9 essential amino acids that our body is unable to synthesize on its own- we must consume these 9 via food to acquire them into our system. So, is a protein a protein a protein? All together now… no! It’s important to get a variety of protein so that we get those 9 essential amino acids that our body cannot synthesize.

Protein is the last macronutrient that your body will break down for energy, because its role as our structure is so important.

Summary / TLDR – Protein is a macronutrient that provides 4 calories per gram and amino acids. Proteins are what give structure to our bodies. All proteins are composed of 21 amino acids. Our body can make 12 of these, but the other 9 must be consumed in order for our body to have access to them.

What else should I know?

Vitamins help our nervous system run, our eyes see, our bodies create blood cells, our immune and digestive systems function, and so much more. There are 13 different vitamins, and they come from a variety of sources! Fat-soluble vitamins come from meats, eggs, and oils, whereas water-soluble vitamins come from fruit, vegetables, and grains. Vitamins can easily be destroyed by exposure to light, heat, or time. Boiling vegetables destroys more vitamins than grilling or steaming (9). This is just one reason why a varied diet is best! Baked cauliflower quiche for breakfast, sauteed zucchini squash medley for lunch, raw snap peas for a snack, steamed carrot and pea medley for dinner! 

Minerals include potassium, calcium, zinc, iron, iodine, and more. These minerals help build bones, move oxygen through our body, regulate hormones, and on and on. We get minerals from all sorts of foods: grain, meat, vegetables, nuts, fruit… and more! There are a lot of factors that affect our ability to absorb those things from our food as well. 

Take iron, for example. There is iron in spinach, and there is iron in meat. But there is a big difference in the bioavailability of that iron. In meat, some of the iron is already bound to blood and muscle (referred to as heme iron) in a way that is similar to how our body needs to use the iron. Once it’s eaten, it’s readily absorbed (14% – 18%) and put to use by our bodies. In contrast, the iron in spinach is nonheme iron, and we are only able to absorb 5%- 12%. On top of that, consumption of minerals can affect how well other minerals are absorbed. For example, calcium and zinc are absorbed by the same channels in our body, so if you take calcium supplements and zinc supplements at the same time, you’re not absorbing as much of either one as you would be taking one supplement in the morning and the other at night (8).

We need a large variety of both vitamins and minerals to have a healthy body. Vitamins and minerals come from a huge variety of dietary sources and are affected by a variety of factors such as method of preparation and even how and when we consume them.

About The Author

personal trainer cassidy Cassidy Slabaugh recently moved to Nashville from Raleigh. She graduated from NC State University in 2017 with an undergraduate degree in Nutrition Science, and received a personal training certification through NASM in June 2017. She is currently finishing the  Fitness Nutrition Specialization. Cassidy is heavily involved in circus, aerial acrobatics, and ninja training.