weight loss diet

Step-By-Step to Plan the Perfect Weight Loss Diet

Planning a weight loss diet can be a struggle for some people, probably including you. Trying to rush your ass off, getting results as fast as possible, or making it so severe that compromise your health.... And these are just some of the reasons why so many people give up dieting and go back on track to their old habits.

But it's way simpler than that (or at least we'll make it simple here). Weight loss has to be understood as a long-term process. Build habits to mantain your weight without even thinking about it.

In this post we'll go trough an step by step on how to perform a perfect weight loss diet, to further discuss some considerations to make it even easier and more enjoyable.

What Do We Mean by Weight Loss?

Weight loss is defined as a decrease in body weight resulting from either voluntary (diet, exercise) or involuntary (illness) circumstances (source). In our case, this will be voluntarily induced by means of diet and physical exercise.

To start with our weight loss diet, we must induce a calorie deficit. Although it's not the whole cake, it's a big chunk of it, and without it we won't have any weight loss at all (study).

But what are calories? How do I know if I'm in a calorie deficit?

What are Calories?

Calorie is nothing you can touch or see. Calorie is an energy unit. It's the energy needed to raise the temperature of 1 gram of water through 1 °C (source). In food terms, this unit is multiplied by a thousand, and we'll have kilocalories (kcal).

It's a way of measuring the amount of energy prvovided by each food based on the specific amount of that food being eaten.

Thanks to scientific research and calorimetric studies, we can know the kcal provided by each of the macronutrients. While carbohydrates and proteins provide 4 kcal/g, fats go above that, providing a total of 9 kcal/g (study). Based on that knowledge and the macronutrient composition of foods, we can know approx. how much energy we'll obtain per food.

Calorie balance

We obtain calories from food, but we also burn calories. Our metabolism needs to burn calories in order to perform all metabolic actions and keep up with our everyday life.

Almost every metabolic process requires of energy. Inmune response, inflammation, creation of new biomolecules, protein synthesis,.... These are all endergonic processes, and energy is absorbed in order to carry out the specific function.

Now we know of two terms to consider: calorie intake and calorie expenditure. Based on these, we can have different scenarios:

  1. Calorie intake > calorie expenditure = Calorie surplus
  2. Calorie intake = calorie expenditure = Manteinance calories
  3. Calorie intake < calorie expenditure = Calorie deficit

As you may have guessed, all three scenarios determine our "calorie status" and whether we'll gain weight (calorie surplus), mantain it (manteinance calories) or lose it (calorie deficit).

Calorie Balance for Weight Loss Diet

How to Start Planning your Weight Loss Diet

Now let's get into matter. We now know the concept of calories and how they can determine our weight loss.

In this step-by-step, you'll be able to plan the perfect weight loss diet that adheres to you and your lifestyle, and enables to lose weight while keeping the optimum body composition.


  • Step 1: Calculate Mainteinance Calories
  • Step 2: Plan macronutrients content
  • Step 3: Test the calculate Mainteinance Calories
  • Step 4: Evaluate the progress
  • Step 5: Make changes depending on your needs and goals

Step 1: Calculate the Theoretical Manteinance Calories

There are many formulas out there to approximate your Basal Metabolic Rate (BMR). Harris-Benedict was the first one and has been used widely, but it's definitely not the most accurate one. In fact, Mifflin-St Jeor Equation (1990) has been shown to be more accurate and less biased for predicting the BMR (study) (systematic review).

Mifflin-St Jeor Equation:
For men:
BMR = 10W + 6.25H - 5A + 5
For women:
BMR = 10W + 6.25H - 5A - 161
W = body weight (kg)
H = body height (cm)
A = age (years)
Once you have the calories from this equation, you'll need to multiply it by the activity factor. This will take into consideration the amounf of energy spent on 'extra' activities such as walking, doing exercise, biking,... (see table below)
To end with, the thermic effect of foods will account for 10% of the energy (study). Thus, multiply the last number obtained by 1.1 to get your final manteinance calories.
TTE = total energy expenditure
AF = acitivity factor
TEF = termic effect of foods
Activity Factor

Step 2: Plan the macronutrients content

Now that you have the amount of calories to intake, the next step to plan your weight loss diet is to look at the macronutrients ratio. Really, this highly depends on you lifestyle and what you like, but we can still give you some general recommendations to start from a good point:

  • Mantain protein high. Aim for 2.2-2.8g/kg of daily protein
  • Fill the left calories by the desired fat-carbohydrates ratio
  • Don't go below 0.3-0.5g/kg fat to avoid health consequences
  • Similarly, try to stay above 0.5g/kg carbohydrates

While the protein intake usually stays constant, the other two macronutrients differ depending on how you want to carry out your weight loss diet. If you are going for a 'normal' diet, I'd recommend you ratio carbs/fat of 60/40. However, your fat intake may increase up to 60-80% of your calorie intake if following a low-carb or, even more, a ketogenic diet.


Jhon has calculated his manteinance calories, which are 2600kcal. He is now 75kg, and with an estimated %fat mass of nearly 14%. He practices resistance training 3-4x / week, and wants to perform a weight loss diet that 1) mantains as much muscle as possible, and 2) doesn't deteriorate his training performance too much.

To do that, we'll take the following considerations:

  • He'll be eating 2.5g/kg protein, which are equal to 188g. Since we know that 1g of protein is 4kcal, then the calorie intake from proteins will be 750kcal.
  • After the protein intake, we are with 1850kcal left. Since he wants to mantain as high as possible his performance, we decide to keep carbohydrates high and go for a ratio carbs/fats of 60/40. This will give 1110kcal and 740kcal, respectively. Coverting to grams for both carbohydrates and fats we obtain 278g and 82g, respectively.
  • So, after all, we have a diet of 2600kcal with 188g protein, 278 carbohydrates and 82g fats.

Step 3: Test your “manteinance calories”

Note that the term is within "" to give a non-reliable aspect. Formulas are good for giving an approximation on where your manteinance calorie may be, but expect them to be slightly off 95% of the times. But you can fix that easily.

Here we start with our "trial and error". Test your calculated calories and macronutrients for at least 2 weeks to give time to your body to adapt to the new calorie intake and stablish a weight loss (or gain) rate.

Take objective measurements such as body weight, muscle perimetres, skinfolds... to evaluate your progress. Here we may have different outcomes:

  1. Weight has increased: decrease calorie intake by 300-400kcal and try again for 2 more weeks
  2. Weight has mantained: you got it! You found your current manteinance calories.
  3. Weight has dropped: here you can do two things. First option, leave the calories as they are and keep with the weight loss, assuming manteinance calories from your weight loss rate. If you are losing 1lb per week, you are most likely to be in a 500kcal deficit (manteinance kcal = current kcal + deficit). Second option, if you don't want to hurry, increase calorie intake by 300-400kcal and start losing weight from there.

Regardless the point at where you are, it's important to make the apropiate and needed changes. It might take longer than expected, but it's also a nice way to get to know your metabolism and the ability of it to gain/lose weight for future perspectives.

Step 4: Evaluate the process

"You can't improve what you don't measure" -  Gray MacKenzie

Taking action and starting the weight loss diet is the first step, but that's not all. You need to take periodical objective measurements to evaluate the process. These will enable to make sure you are losing weight at the rate you want while keeping the max. amount of muscle and improving your body composition.

Objective Measurements

1)Weight Scale

This is the most used method to evaluate changes in the weight. Get on the scale every day and take the week average. Compare with past weeks and analyze it. If you don't like weighting yourself everyday, go for 2-3 days, but they need to be the same days.

To decrease margin of error, use the scale under the same circumstances all the time. These include first time in the morning, without any food in your stomach, only in underwear and after going to the bathroom

2) Muscle Perimeters

Muscle perimeters are associated with muscle strength and body composition (study)(study), giving reliable data about our progress.

Take a measuring tape and take the perimeters once a week (possibly right after waking up and going to the bathroom). In the picture below you'll se a guide to where to measure. You don't have to go for all of the mentioned, though. Just measure the ones you think are reliable and give you enough data to evaluate and analyze the process.

Muscle Perimeters

3) Skinfolds

Skinfolds enable us to predict our %fat by measuring the thickness of our surface skin layer and the tissues behind (study). They required of instrumentation (fat caliper) and experience in order to get reliable data.

To get the most out of it, take a reference of each fold the first day of measurements, and use that to take the same measurements every time. On the figure you can see the folds needed to determine body composition.

DAPA Measurement Toolkit

Subjective measurements

We have to base our evaluation on objective measurements, but subjective also give us some useful data to analyze how the weight loss is going.

The most important one here is how well you are feeling. Take pictures under same circumstances, evaluate your hunger and food anxiety, feel the pump after your workout or the sports performance. There are many ways to evaluate the process, but again, be consistent with your methods and procedures.

Step 5: Be open for changes

You have to see your metabolism as a dynamic soul instead of an static "black box". As we are dieting and inducing calorie deficit, metabolic adaptations will eventually take place (study), creating energy imbalances and shifting your manteinance calories.

These metabolic adaptations will define your dietary changes through your weight loss. If you feel like you are reaching a plateau and weight is not dropping, it's time to make some changes. Here you can mainly go for two options:

  1. Increase your physical activity (other than your normal training). E.g: do a longer session of LISS, or an extra session of HIIT
  2. Decrease your calorie intake. Go down 200-300kcal on your calorie intake and evaluate how your body responds.

Both options lead to the same; increase the calorie deficit. On the first option, we are increasing our calorie expenditure, while the second points more toward decreasing the calorie intake. As we saw above:

Total energy balance = calorie intake - calorie expenditure

Both terms influence on the total energy balance, and a decrease on the first and/or an increase on the second one will make the total energy balance to be more negative, which is requirement #1 when it comes to weight loss.

Weight Loss Diet

Considerations for your Weight Loss Diet

Now you know what to do to build your perfect weight loss diet. But there are some aspects you may want to change in order to improve adherence and make the process easier and more enjoyable. Although they are not universal and don't work well for everyone, I find them very useful and totally recommended when it comes to weight loss.

Include high amounts of fiber

Fiber are non-digestible carbohydrates found mainly in plant sources (study). Their intake has been associated with many health benefits, including low risk of coronary heart disease, regulation of the gut microbiota or gastrointestinal health (study).

In terms of weight loss and body composition, we have seen in studies how a higher intake of fiber leads to a higher calorie expenditure and lower calorie intake (study). In addition to that, soluble fiber increases satiety by creating a gel in our stomach and occupying volume in there (study).

The thermic effect of fibre is higher than other foods, and more energy is used on its "digestion" and "absorption" (some will never be digested). Therefore, we spend more energy trying to digest fiber, and the calorie expenditure slightly increases (study)

Proritize protein intakes

As it happens with dietary fiber, protein has a higher thermic effect than carbohydrates or fats. Approx. 25% of the energy provided by proteins is used on its digestion and absorption (study), which is way higher when compared to carbs and fats. This means that higher protein intakes will lead to higher thermic effect and energy expenditure.

Besides the thermic effect, protein is the main source of amino acids in our organism. During a weight loss diet, one of our priorities is to keep as much muscle mass as possible, and protein can help us on that (study). Higher protein intakes have been associated with higher preservationn of muscle mass and improved body composition.

Choose the right food selection

Adherence is the king of a weight loss diet. Long term determines not only how succesful your diet has been, but also how well you'll do mantaining the weight after dieting.

Eating something you don't like or enjoy is simply not gonna work. Enjoy food and choose the right selection of foods. Nowadays, in a globalized market, there are always better alternatives to the food you don't like.

If you are willing to plan a "closed weight loss diet" I still recommend you having 2-3 options for each meal with different foods. Some days you may feel like you are bored of certain foods, and a change will take you out of that monotony.

Don’t forget your micronutrients

So far we have only talked about calories and macronutrients, but micronutrients are also a big 'chunk' of the equation. They are involved in thousands of metabolic processes, and deficiency on them can cause severe health consequences (study).

But you are fortunate here. Low-calorie density foods such as vegetables and fruits are known as the most nutritional dense foods of all (study). And they are perfect for your weight loss diet. Containing fiber and being low in calories, they enable you to be more satiated, increase your energy expenditure and still have more calories to eat later on the day.

The recommended protocol to reach all micronutrients is to guide yourself by colors. It seems like different colors in vegetables contain different vitamins and minerals. Eating from the whole color spectrum is an easy way to ensure the right micronutrient intake (read more about that here).

Follow different calorie strategies

Although a linear calorie deficit is always the first and traditional option to make a weight loss diet, you can play with the different days of the week to have 'high-calories' and 'low-calories' (study).

However, on a weight loss diet, the overall calorie deficit is what matters the most. There's no benefits on doing the intermittent dieting if, at the end of the week, the calorie deficit is the same.

Intermittent dieting, however, may help you having more calories on certain days (e.g: during the weekend) and still achieve your calorie deficit.

You could place the high-calorie days on training days, and lower the calories on rest days because of the lower energy requirement those days.

What Do I Do After the Weight Loss Diet

You have been losing weight for 5-6 months now, and you start being happy with your body and %fat. Should I stop now, wait, maintain calories...?

Your body has created metabolic adaptations along the weight loss diet. Your metabolism has adapted to the low-energy status and it now needs less calories to survive than before (study). So, if you go back to your 'manteinance calories', you'll most likely be gaining a lot of weight (and some fat) after the weight loss diet. To avoid this, I recommend doing what's called reverse dieting (source).

In simple terms, reverse dieting is about increasing your calorie intake slowly and linearly through the weeks, until you reach back the mainteinance calories. By doing this, you'll avoid the 'yo-yo effect' an sudden weight and fat gain afterwards.

Increase calories by 200kcal (the first weeks can be a bit more) every 1-2 weeks, and evaluate body composition and weight by means of both objective and subjective measurements.

Weight Loss Diet to Improve your Physique

By doing a Weight Loss Diet, we can lower our body fat and improve our physique. But that's not enough. If you want the best results and the physique you were looking for, you need to consider more factors. Training, recovery, sleep,...

In this course, we explain all you need to know to optimize the process of muscle building and body composition. From the principles of muscle building and a training program, to sports nutrition and the most important aspects to optimize the process. And all this with a defined goal; get you the best physique and create a healthy and sustainable lifestyle.


Start Changing Your Physique


Weight Loss is complicated if not planned. In this post we've seen all the step-by-step to plan and design your perfect weight loss diet. As you know now, there are many aspects to consider, and if you want to success, they should be carefully put in the equation of weight loss.

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