3 Key Principles of Diet Planning You Need To Know

I think that everyone would agree, that dieting is by far the most difficult component of a fitness routine.

Just take a look at the national dietary recommendations- they seem to change just as often as you change your underwear.

With so many different dietary recommendations out there, how could you possibly know which one is right for you?

Thankfully, there are a few key metrics you can look towards to inform your decisions.

Anyone who has been training for a significant amount of time understands these 3 basic principles of diet planning. Making any kind of modification to your diet can alter your energy levels, your performance, and most of all your lean muscle mass and body fat percentage.

3 key principles of diet planning everyone ought to know cover image

Welcome to The White Coat Trainer series on diets.

Today’s post will teach you what a balanced diet is, and illustrate 3 key principles that most diets utilize.

In Part 2 How to Stop Counting Calories and Part 3 How to Start Eating Clean With a Busy Schedule, we share several dieting tips that you could begin to implement right away into your busy schedule.

Alright, let’s get to it…

What is a Balanced Diet?

In order for a diet to be successful, it has to be balanced.

What do we mean by that?

A balanced diet is one that contains an adequate proportion of the three major macronutrients: Protein, Fat and Carbohydrates. 

That is not all.

A balanced diet must also contain an adequate amount of ALL the essential vitamins and minerals, the micronutrients

This is where most diets fail. 

You cannot just expect to get your required macronutrients and call it a day. The reason why these vitamins and minerals are essential is that your body actually needs them.

Just look up any random vitamin or mineral and look up its function. Guess what? If you lack that micronutrient in your diet, then your body won’t be doing any of those things optimally.

According to the CDC, nutrient deficiencies are prevalent in America.

This then begs the question: how are people surviving if so many of them lack adequate micronutrient intake?

The answer is rather simple. The human body is an AMAZING machine.

Your body will adapt and make do with whatever it is getting from the diet!

Now does that mean your body is running optimally?


Will all of your hormones (especially the ones responsible for metabolism) be functioning at their highest capacity?

Definitely not.

You have to look at your diet from a holistic point of view.  Not giving your cells the nutrition they require will have downstream effects elsewhere. Everything is tied together.

So if you want to have a successful diet, you must balance your diet first.

This is the benefit of having a balanced diet. A balanced diet will

  • keep your body running smoothly,
  • keep your hormones in check,
  • help you maintain a healthy body weight,
  • provide you with energy
  • improve your sleep.

Now that we have convinced you of balancing your diet, let’s go over three principles that all diets must follow…


We all have a general idea of which foods we should avoid, and which foods we should eat more of.

However, you probably have very little knowledge as to how many calories you actually consume on a daily basis. 

The total amount of calories you eat must be balanced by the number of calories your body utilizes.

It follows the first law of thermodynamics.

Energy is transferred from the food that you consume to your body, which will either be used immediately or stored for use at a later time.

Calories in = Calories out.

Following this logic, it does not matter how many “healthy” or “unhealthy” foods you eat- if you eat more calories than you can burn, your body will gain weight. If you burn more calories than you eat, you will lose weight.

We have several examples of this in real life. Take a look at Michael Phelps- the individual with the most gold medals in the history of the Olympics.

While training for a competition he would consume 8,000+ calories a day, of what most people would consider being ‘unhealthy’ foods.

Yet, he was able to maintain elite athletic performance and low levels of body fat due to his intense exercise regimen and fast metabolism.

However, Calories In = Calories Out Does Have Some Limitations

Calories in = calories out is a very simplistic model.

We all know that real life is a lot more complicated than that.

Here are some limitations to this approach.

1. It is extremely difficult to know how many calories your body is actually burning. There are many factors that contribute to this part of the equation including your metabolic rate, and your exercise and non-exercise activity levels. The genetic variation here is enormous!

2. Counting calories is also extremely difficult, as there is a large margin of error on nutrition labels and any calculations you make will be an estimation at best.

and most importantly

3. If you drop your caloric intake by too large an amount, you will ultimately become malnourished, and cause a sharp decrease in your metabolism.

If you simply consume fewer and fewer calories to lose weight, your body’s self-defense mechanisms will kick into gear. 

It will do what it can to preserve body weight, and slow down energy consumption. Once you stop the low-calorie diet, it is only downhill from there.

You don’t need to look further than the contestants from “The Biggest Losers.”

These individuals lost upwards of 80-100 lbs, through extreme caloric restriction, only to gain it all back, and more, due to a slower metabolism.

The Biggest Loser also made it seem like exercise plays a very big role in weight loss.  Sadly, exercise is only 20% of the equation which we discuss here.

So while total calorie consumption is important, it is important that you manipulate your total energy balance strategically.

To recap:

  • Total energy balance (caloric intake vs caloric expenditure) is the biggest factor contributing to your bodyweight.
  • All diets work by decreasing the “calories in” portion of the equation, while increasing the “calories out” portion of the equation.
  • Estimating how many calories you consume (“calories in”) is difficult and often imprecise
  • The number of calories your body burns (“calories out”) is determined by your metabolic rate, how much exercise you do, and how many calories your body burns doing non-exercise activity.


The next contributor to successful dieting is paying attention to your macronutrient intake.

As we mentioned before, a balanced diet has an adequate proportion of the three major macronutrients: Proteins, Carbohydrates, and Fats.

Almost all foods can be classified into one of these three groups, and it’s important to be able to identify which food falls under which category.

The ratio of these three nutrients in your total daily intake is where most diets vary significantly.

Almost all diets advocate for some combination of low fat, low carb, or high fat, high carb variations to achieve the desired result.

Let’s go over the three macronutrients one by one.


Protein is by far the most important macronutrient, and the one people usually eat the least of.  

This is a big mistake, as high protein foods keep you satiated, and serve as the primary building blocks for muscle toning and muscle strengthening.

According to general nutrition labels, an average woman consuming 2000 calories a day should aim to have 50g of protein per day, and an average man consuming 2500 calories a day should have 65g of protein.

These values are actually quite low, and anyone who performs athletic activities understands the importance of consuming enough protein to fuel their body.

Ideally, protein should account for 20-40% of your total caloric intake which may be anywhere from 90-200+g of protein per day depending on your body weight and goals.

High-quality sources of protein include

  • lean meats,
  • fish,
  • eggs,
  • whole milk, and
  •  Greek yogurt.

If you are plant-based like we are, you can use


Fats are the next most important macronutrient.

Your body utilizes fats for padding and insulation, as substrates for many hormones, and to solubilize Vitamins A, D, E, and K.

Fats come in different varieties; saturated, monounsaturated, polyunsaturated, and trans.

Unsaturated fats are considered to be the healthiest, while trans fats are to be avoided at all costs.

Unsaturated fats can be obtained from healthy oils such as extra virgin olive oil, fish oil, and avocado oil.

Other sources include 85% dark chocolate (cacao), and different nut varieties.

A very common misconception is that high fat consumption is what makes you fat.

This is absolutely false.

Excessive calorie consumption, of the wrong types of food, coupled with little physical activity (and of course, your genetics) is what contributes to elevated body fat levels.

Again, fat intake can account for 20-40% of your total caloric intake depending on your body weight and goals.

This means that you can consume anywhere from 50-120g per day with the majority of this intake coming from unsaturated sources.


Carbohydrates are the least important macronutrient of the three. They serve as the primary source of energy for your brain, and they are used to maintain glucose levels in your bloodstream.

If you happen to stop eating carbohydrates (from non-fruit and non-veggie sources) you would actually be perfectly fine.

In absolute carbohydrate depletion, your body would begin to use up other sources (such as fat) for energy, in a process known as ketosis, (we have written about The Keto Diet extensively here).

While I do not necessarily recommend this approach, many elite level athletes have successfully used ketosis to achieve high levels of performance.

If eaten in excess your body will store carbohydrates first as glycogen, and then ultimately as fat.

image of white bread

An enormous amount of low quality food choices fall under the category of carbohydrates; most of which have a very high glycemic index.

In other words, they are simple sugars that raise your blood glucose rapidly, leading to large fluctuations in insulin levels.

Excessive consumption of high glycemic foods has been linked to the development of Type II Diabetes Mellitus and metabolic syndrome.

Examples of high glycemic carbs include white bread, regular pasta, white rice, and baked goods such as cakes and cookies.

Similar to Proteins and Fats, Carbohydrates can make up 20-40% of your total caloric intake depending on your body weight and your goals.

It is a good rule of thumb to obtain a large part of your carbohydrates from low glycemic fruits and non-starchy vegetable sources.  

It outlines all of the healthiest foods from each macronutrient, as well as the foods you should avoid!

In a nutshell…

  • Proteins is absolutely essential to maintain a healthy amount of lean muscle.  These foods should be eaten as often as possible.
  • Fats is also absolutely essential for hormone production and insulation. Ensure that the fats you consume in your diet are high quality.
  • Carbohydrates are routinely eaten in excess and should be eaten in moderation, especially if you are not very active.

And now, onto the final principle.



The third principle of dieting that you must pay attention to is food composition. This refers to the quality of the macronutrients you are consuming.  

While this principle is not as important as the first 2, it is still important for you consume whole foods that are minimally processed.

This means that they are as close to their natural state as possible.

High-quality protein, healthy fats, fruits, and vegetables need to be staples in your diet to provide optimal results.


Because high-quality foods are more likely to be full of nutrients than their low-quality counterparts. This is how you will obtain all of the micronutrients we have described above.

It is not necessary to buy organic, as there is no definitive evidence detecting significant differences in individuals consuming organic versus conventional foods.

A good rule of thumb to follow is – try your best to avoid foods that didn’t exist a thousand years ago.

Cookies, ice cream, french fries and other low-quality foods have to be kept to a minimum. You don’t have to cut these foods out completely, but you must keep them in check.


So there you have it.

You now understand what a balanced diet is, and the 3 principles of diet planning you must utilize if you are to optimize your nutrient intake.

To recap,

  • A balanced diet provides 20-40% of each macronutrient and focuses on consuming an adequate amount of all micronutrients
  • Altering your total caloric balance will lead to weight loss or weight gain over time
  • Proteins and Fats are essential macronutrients, eat them often and frequently
  • Starchy carbs need to be minimized, and the majority of your carbs should come from green vegetables and low GI fruits
  • Eat foods that can be found in nature as often as possible

Now we can get to the nitty-gritty of how to actually eat.

In Part 2, How to Diet without Counting Calories we discuss how to analyze your meals and determine how much food you should be eating.


Alex Robles, MD, CPT / Brittany Robles, MD, MPH, CPT

Alex & Brittany Robles are physicians, NASM Certified Personal Trainers, and founders of The White Coat Trainer: a resource dedicated to improving the health and fitness of busy professionals using time-efficient strategies. Their advice has been featured in My Fitness Pal, Prevention, Livestrong, Reader’s Digest, Bustle, The Active Times, and more. Learn more about them here.

2 thoughts on “3 Key Principles of Diet Planning You Need To Know”

  1. Hi – Ive signed up for the food list that shows all healthy foods and foods to avoid twice now and I have not received it in my email yet. How long does it take? Thanks,

Leave a Comment