Eat It: Complete Guide on Quantitative Weight Management

Table of Contents


This guide is designed to help you tailor your nutrition based on your fitness objectives. Proper nutrition is as crucial for achieving fitness goals as it is for maintaining overall health. By managing your diet effectively, you can experience significant changes in your appearance far quicker than with exercise alone. Without adjusting your diet, it may take months or even years to see the same results.

Achieving fitness goals depends heavily on how well you fuel your body with energy (calories) and nutrients (both macro and micro).

Comprehensive Energy Guide

Total Daily Energy Expenditure = Basic Metabolic Rate + Daily Activity Level + Exercise + Energy for Digestion

1. Basic Metabolic Rate

Imagine it’s a lazy Saturday. John has been lounging on the couch binge-watching Netflix since noon. Even without much movement, his body has burned at least 1,000 calories in 24 hours just maintaining basic functions.

If John consumes fewer calories than his body needs for daily activities and basic metabolic functions, his body will start to use its internal energy stores. This process begins with carbohydrates and muscle protein, and only as a last resort, does it tap into fat reserves, which the body is typically reluctant to use.

We’ll explore strategies later in this guide to help preserve muscle mass while efficiently burning fat.

2. Daily Activity Level

Consider all the activities that fill your day—commuting, studying, walking the dog, or browsing online. Activities you barely notice still consume energy:

These actions account for 10% to 30% of your daily energy expenditure, making it the second-largest energy consumer after your basal metabolic rate.

In energy deficit situations, your body will adjust by reducing these daily activities, preserving energy for vital functions, resulting in a slower and more lethargic demeanor.

3. Exercise

Exercise burns energy by the amount dependent on the intensity and duration of the workout. On average, fitness-related exercises account for about 10% of your daily energy use, with typical gym sessions burning around 150-200 calories.

4. Energy for Digestion (Thermic Effect of Food)

Approximately 10% of your daily energy goes into digesting, absorbing, and excreting food. Each macronutrient takes different mount of energy for digestion:

Now you know where your energy goes:

Total daily energy expenditure = Basic Metabolic Rate + Non-Exercise Activity + Exercise + Thermic Effect of Food (TEF).

While the daily energy expenditure can vary due to different meals, activity levels, and other factors, maintaining a balance between the calories you consume and those you expend is essential for managing your fitness and health.

Key Macronutrients

To lose weight, you need to consume less energy than you expend. This principle is not only consistently supported by scientific research, but also is a fundamental law of physics.

If you focus solely on calorie count, weight loss is indeed possible. However, it’s much more enjoyable to have a toned and fit body rather than just seeing nice numbers on the scale.

This brings us to body composition - the ratio of muscle to fat. When losing weight, it’s important to lose fat, not muscle. Therefore, you need to control not only the deficit but also the balance of macronutrients - proteins, carbohydrates, and fats (the famous PCF ratio). Knowing the exact amounts of these nutrients in your diet helps you keep your trained body strong and healthy while avoiding excess body fat.

Each of the three macronutrients has its own energy value:

1. Protein

Proteins consist of amino acids linked together that participate in many processes in our body. Protein is not just for quelling hunger - virtually nothing in our metabolism occurs without it.

Important anabolic hormones like insulin, growth hormone, and insulin-like growth factor, among many others, are protein-based. Enzymes and kinases (cellular signaling complexes) are also proteins. Transport systems, ion channels, the immune system, fluid level control, and body acidity balance are all protein structures.

Consuming protein is vital for tissue building and metabolic processes. This crucial macronutrient consists of 20 basic amino acids, nine of which are considered essential. Our body cannot produce these, so we get them from food.

Providing the body with sufficient protein:

How Much Protein Should You Consume Daily?

The amount depends on your goals.

To gain muscle mass and maintain it, you should consume 1.6 to 1.8 grams of protein per kilogram of body weight.

For weight loss, the protein intake can be increased to prevent muscle breakdown during calorie deficit. Under such challenging conditions, the protein intake should increase to 2.0-2.2 grams per kilogram of body weight.

If you have more than 30% excess body fat, protein requirements are calculated based on lean body mass. Lean body mass = total body weight minus fat weight. You can find this parameter through a body composition analysis (bioimpedance analysis), which will show how many kilograms of fat are in your body. Subtract this from your total weight and multiply the remaining mass by the protein intake range provided above.

For example, if you weigh 80 kg and bioimpedance analysis shows you have 25 kg of fat, your lean body mass is 55 kg. To find your protein requirement, multiply 55 by the appropriate dosage.


Don’t listen to those who say high protein dosages are toxic and dangerous, except if you have kidney problems, in which case you should consult a doctor about protein intake. For those without kidney problems, there’s nothing to worry about. Modern research confirms the safety of the protein dosage range mentioned above.

If you’re a vegan and rely solely on plant-based sources of protein, either opt for the upper end of the protein intake range or include branched-chain amino acids (BCAAs) in your diet. Plant proteins lack a full amino acid profile, particularly lysine and leucine. Leucine is crucial for initiating muscle protein synthesis in cells. To compensate for the lack of a complete amino acid profile, increase protein intake by at least 20% or include amino acid supplements in your diet.

2. Carbohydrates

Carbohydrates aren’t essential for survival, as the body can manage without them in extreme situations. However, they do have their advantages and, let’s face it, they taste great.

Carbohydrates come in different forms:

In the digestive system, all carbohydrates break down into monosaccharides, entering the bloodstream as simple sugars, except for fiber.


Glucose is crucial for our survival. The body needs 100-120 grams of glucose daily. The liver synthesizes it when dietary carbohydrates are lacking and stores it as glycogen in the liver and muscles.

Glucose is essential for red blood cells and the brain. For those who do strength exercises, glucose is vital for high-intensity anaerobic muscle work, like challenging barbell sets to the point of failure.

ATP (Adenosine triphosphate), the main energy molecule in our muscles, can’t be quickly replenished from fats to continue exercising. Glycogen stores in muscles are used for this.

Carbohydrates are often blamed for weight gain, but the real culprit is excess energy in the body, regardless of whether it comes from proteins, fats, or carbohydrates. The process of converting glucose to fat is called lipogenesis. If you don’t overeat, it occurs in minimal amounts.

Another accusation is that carbohydrates cause insulin secretion, an anabolic hormone that blocks fat burning. This fear stems from misunderstanding insulin’s functions and secretion patterns.


Not only carbohydrates but also proteins increase insulin secretion. Many fear these secretion peaks, but this concern is only relevant for diabetics. For others, increased insulin secretion is normal and unrelated to weight gain. Moreover, insulin causes a feeling of fullness, so those avoiding fruits, for example, face constant hunger.

Glycemic Index

The glycemic index requires explanation, as it’s often used to scare people. It was developed in the 1980s to help prevent type 2 diabetes. The index indicates how quickly glucose enters the bloodstream; the higher it is, the faster sugar reaches the blood.

In theory, by choosing foods with a low glycemic index, people aim to avoid increased insulin secretion, which is supposedly responsible for weight gain. However, all research on this topic has disproved the theory of the danger of a high glycemic index. It has been proven that for healthy people, if you’re within maintenance calories or in a deficit, the index doesn’t matter at all.

Practical Advice on Carbohydrates

Here’s a practical tip for you: Prioritize complex carbohydrates rich in fiber in your diet, mainly vegetables, followed by fruits. These foods have a high satiety index and are packed with beneficial minerals and vitamins. You’ll feel less hungry and they’re healthier.

You can also enjoy simple carbohydrates from processed foods (baked goods, fast food, candies, sweets). However, they have high calorie density, low nutritional value in terms of macro- and micronutrients, and hardly provide any satiety. It’s best not to overindulge.

Carbohydrates in Your Diet

With the basics of carbohydrates covered, let’s determine how much you need.

Muscle Gain

To build muscle on a calorie surplus, you need to consume 4-6 grams of carbohydrates per kilogram of body weight per day. If you have insulin resistance (detected through tests), your limit is up to 2 grams per kilogram of body weight per day.

Weight Loss

For weight loss, there are no precise figures or ratios for macronutrients. I’ll later explain how to create your own ratio of calories, proteins, fats, and carbohydrates.

3. Fats

Fats, also known as lipids, come in various forms:

Unlike carbohydrates, fats are essential macronutrients, as our bodies can’t synthesize certain vital fatty acids. Lipids participate in many metabolic processes:

Fats are excellent energy stores, as they provide twice as much energy as proteins or carbohydrates - 9 calories per gram!

Types of Fats

Not all fats are equally beneficial. There are:

  1. Saturated Fats (solid at room temperature) - These should be consumed cautiously. I don’t forbid you from eating them, but they shouldn’t dominate your diet. Limit red meat, sausage, salami, etc., to 2-3 times a week. Prioritize white meat and fish.

  2. Unsaturated Fats (liquid at room temperature) - These are further divided into monounsaturated and polyunsaturated fats, and should be the main source of fatty acids in your diet. Avocado and olive oil are excellent sources of monounsaturated fats.

  3. Omega Fats - Don’t forget the famous “Omega-3” (salmon, flaxseed oil) and “Omega-6” (sunflower oil, walnuts) fats - they should also be part of your diet.

  4. Trans Fats - These should be avoided entirely. They’re artificial substances, cheap replacements for butter - spreads and margarines. Avoid them and eat less fast food, which often contains trans fats.

Fats and Hormones

The level of fats in the diet is crucial for maintaining reproductive hormone secretion. Fats should account for at least 20% of total daily calories. Consuming less impairs testosterone and estrogen production, negatively affecting muscle mass maintenance and reproductive-related hormonal activity.

When balancing macronutrients for weight loss, always choose fats over carbohydrates - they’re more important for health and beauty.

Daily Fat Intake

There’s no fixed medical standard for fat intake. The recommended range is 0.5-1.5 grams per kilogram of body weight. 0.5 grams is about the minimum for health, and exceeding 1.5 grams makes it hard to avoid calorie surplus.


Now, let’s talk about water. While it’s not a macronutrient, it is a crucial component of our bodies. Water is essential for metabolism, and it’s important to drink plenty of it. But what does “plenty” mean?

Water is something we often overlook until it’s lacking in our bodies. When we’re dehydrated, we quickly realize the importance of water. A study by the National Strength and Conditioning Association (NSCA) in the U.S. showed that just a 3-4% decrease in hydration reduces muscular endurance and increases the risk of strains. Therefore, maintaining sufficient water levels is key to good physical condition in the gym.

The state of hydration (how saturated the body is with water) depends on several factors:

Unfortunately, many athletes start their workouts already dehydrated. But the good news is, you can easily check and resolve this issue by following these guidelines:

Water Consumption Guidelines

1. Check the Color of Your Urine

You can tell if you have enough water in your body by checking the color of your urine before a workout. If your hydration level is adequate, your urine will be light and clear. In a dehydrated state, urine will be dark. If this is the case, gradually increase your water intake throughout the day until your urine becomes lighter.

2. Pre-hydrate

To maintain balance, follow this protocol: drink 400-500 ml of water two hours before your workout. This provides your body with enough water before exercise, allowing you to perform at your best.

3. Replenish During Exercise

During your workout, maintain and replenish your water supply. Every 15-20 minutes, depending on the intensity, drink 200-400 ml of water. If you don’t maintain proper hydration, your cardiovascular system becomes strained, and aerobic capacity diminishes. Dehydration also decreases sweating rate, risking overheating. This rule applies to both strength and cardio workouts - you should drink water while running and while lifting weights.

4. Monitor Sweat Loss

Losing 2% of your body weight during exercise indicates dehydration. You can monitor this by weighing yourself before and after a workout. If your weight decreases, replenish it with water or a sports drink.

5. Correct Water Intake

If you’ve lost more than 2% of your body weight during a workout, replace the lost fluid with 150% of that amount in water or a sports drink. For example, if a woman weighing 60 kg drops to 58.8 kg after a workout (2% weight loss), she should drink at least 1.8 liters of water (1.2 kg of lost weight * 150% = 1.8 liters). It’s best to spread this water intake over subsequent workouts - drinking during and after exercise to avoid dehydration.

6. Monitor Salt

When sweating heavily, it’s important to monitor salt levels, which are lost through sweat. You can either taste it (if sweat from your face touches your lips) or notice a white residue on your skin or workout clothes in areas of heavy sweating. You can restore sodium levels by consuming a sports drink containing this mineral. Sodium in a sports drink reduces urine output and helps normalize blood plasma volume.

Macronutrients and Diet

Now that you know all you need about macronutrients and how they function, let’s move on to obtaining proteins, fats, and carbohydrates from food. So, what should you eat to ensure your body gets enough energy?

1. Protein-Rich Foods

2. Carbohydrate-Rich Foods

Carbohydrates can be fast, slow, or insoluble.

a) Advantages of Fast (Simple) Carbohydrates:

b) Advantages of Slow (Complex) Carbohydrates:

c) Fiber (Insoluble Carbohydrates)

I recommend consuming 10-15 grams of fiber for every 1000 calories in your diet. Don’t overdo it, as fiber retains water in the digestive tract. While this is good for satiety, it might cause water retention.

3. Fat-Rich Foods


Small and moderate amounts of alcohol don’t significantly harm body composition, provided you account for its calories as you do for proteins, fats, and carbohydrates.

To Drink or Not to Drink?

Whether or not to consume alcohol and in what amounts is a personal decision. Here’s what happens in the body when you consume alcohol, from a macronutrient perspective:

  1. Any amount of alcohol easily blocks protein synthesis and fat oxidation.

    • While alcohol is in the body, you’re not losing fat or building muscle. These few hours while alcohol is in the bloodstream are lost for progress. The negative effect doesn’t depend on the type of alcohol—whether it’s cognac, mojito, or beer. The larger the dose, the longer the negative effect lasts.
  2. The second downside of alcohol is its calorie content.

    • If you’re planning to drink and maintain your results during a calorie deficit, be sure to count the alcohol in your intake (7 calories per ml of alcohol, or check the bottle for calorie information). Many alcoholic drinks have even higher calories due to additional ingredients.

Energy Balance Glossary

How to Calculate Your Caloric Intake

You can use the following formulas to calculate your caloric intake:

However, there’s no significant difference between them. I recommend using the simplest approach by utilizing a calorie calculator. For example, you can use the calculator on this website:

Step 1: Open the Calculator

Step 2: Set Your Goal

Next, determine your goal for diet and training by selecting one of the following goals (GOAL):

Step 3: Determine Your Activity Level

Next, choose your daily and training activity level (ACTIVITY LEVEL):

Step 4: Calculate

After entering all your current parameters, selected goals, and activity level, click “CALCULATE.”

Step 5: Tools You Need

Next, you’ll need:

Step 6: Implementation

You can do this! Good luck, and have patience and willpower!

Practical Application

Now that you have all the important information about macronutrients and know how to calculate your caloric intake, let’s see how to apply this knowledge in practice.

How to Lose Weight and Maintain Muscle Mass: Instructions

Step 1: Set Your Caloric Deficit

Determine your exact caloric deficit, considering all your activities. For example, let’s take 1500 calories as the baseline for further calculations.

Step 2: Determine Protein Intake

Set the amount of protein in your daily diet. For example, women aged 20-30 who are cutting should have at least 2.0-2.2 grams of protein per kilogram of body weight.

Step 3: Calculate Protein Calories

Calculate how many calories your protein will account for. Suppose you weigh 60 kg. At the lower end of the recommended range (2 grams), you should consume a maximum of 120 grams of protein. In terms of calories, this would be 120 * 4 = 480 calories. Therefore, for fat and carbohydrates, with a baseline of 1500 calories, the remaining calories after protein would be 1020 calories.

Step 4: Adjust Fat and Carbohydrate Ratios

You can adjust the ratio of fats and carbohydrates within the remaining calories after protein. For example, you might want to maintain 1 gram of fat per kilogram of body weight. In our example, this would be 60 grams. Calculating the caloric value of fat gives us 60 * 9 = 540 calories. This leaves 1020 - 540 = 480 calories for carbohydrates, which would be 480 / 4 = 120 grams.

If you settle on this ratio, the macronutrient breakdown would be: proteins 120 grams, fats 60 grams, carbohydrates 120 grams.

Step 5: Distribute Protein Throughout the Day

Human body can store carbohydrates and fats but not protein. Therefore, try to distribute your meals throughout the day such that each meal has a consistent and even amount of protein for muscle growth.

The minimum protein dose per meal that contributes to muscle mass building after intense workouts is 0.3 grams per kilogram of body weight. So, if you weigh 60 kg, each meal should contain at least 20 grams of protein if you aim to maintain your workout results.

Step 6: Distribute Meals as Per Your Convenience

The idea of eating more frequently in smaller portions has remained theoretical despite extensive research. Fractional eating doesn’t increase metabolism or promote weight loss. Therefore, eat as many times a day as is convenient for you—whether 3 or 5 times. The key is to ensure your daily protein intake. Everything else is secondary and can be chosen based on your preference.

Nutrition Around Training

It’s more important to eat a solid meal 1.5-2 hours before training than to rush for a protein shake immediately after. If you eat beforehand, the amino acids from the food will support protein synthesis for both the workout and a few hours after. The next major meal with sufficient protein should be within 2 hours after training.

Sports Nutrition

The key to building a healthy, beautiful, and strong body is proper nutrition:

With this approach, additional sports supplements, if needed, will be minimal.

Sports Supplements You Might Need

1. Protein

Protein helps you meet your protein intake when it’s difficult to do so with regular food (e.g., when traveling or in daily life when you can’t eat properly). For this purpose, whey protein and casein are suitable. Casein digests slowly, making it more suitable for situations with long intervals between meals or before bed.

A scoop of protein usually contains 25-30 grams of amino acids, enough to sustain protein synthesis.

Important! People allergic to dairy protein should be cautious with protein supplements.

2. Pre-Workout Drink

The most valuable intensity stimulant is caffeine, which is well-studied and scientifically proven to be safe. If you don’t have a cardiac restriction on caffeine, you can safely consume it half an hour before training. Caffeine comes in capsules, pre-workout drinks, or simply in a cup of hot, aromatic coffee, which mobilizes the nervous system for focus during training.

An effective dose before training is between 200 and 400 mg. Start with the minimum dose to assess your tolerance.

3. Creatine

Creatine is an excellent supplement that helps the body quickly replenish energy. With it, you can train with greater intensity and volume, pushing your fatigue threshold further.

Advantages of creatine:

Take creatine regularly, once a day. Timing isn’t critical.

4. Fish Oil

Omega-3 fatty acids are essentially not sports supplements but essential macronutrients. Regardless of your fitness goals, this supplement is beneficial for everyone. Fish oil easily compensates for the lack of healthy fats, especially if you don’t like fish or eat it less than twice a week.

Benefits of fish oil:

Like creatine, fish oil has a cumulative effect, so the timing of intake isn’t critical. Regularity is what matters. It’s advisable to take it with meals for better digestion. The minimum dose is 1 gram daily, but more is recommended—this is one case where you can’t go wrong with “too much of a good thing.”

Side Effects of Fish Oil

Side effects may be experienced by those allergic to seafood. People taking blood pressure medication should also be cautious.

Progress Speed

We often think of progress in fitness as visual changes in physique, though that’s not the only benefit of exercising. Let’s clarify the visual changes you can expect if your diet is well-calculated and strictly followed, and your training, whether in the gym or at home, is intense and regular.

1. Progress in Weight Loss

Set a realistic rate of subcutaneous fat loss: 0.5%-1% of body weight. The more excess weight you have, the faster it goes away with physical exercise. The closer you are to your goal, the slower the process.

Example: Our hypothetical John from the start of this guide is tired of lounging on the couch watching shows and wants to lose weight from 85 kg to 80 kg. 0.5% of 85 kg is 425 g per week, so he’ll lose about 1700 g in a month. He will reach his goal in 11-13 weeks.

Remember, weight loss isn’t linear. You’ll face:

These are realistic numbers if you want to lose fat while maintaining muscle mass, provided you track your nutrition with discipline and responsibility.

2. Progress in Muscle Gain

What progress should you expect when gaining muscle mass? The rate of gain depends heavily on training intensity and genetics and is independent of gender. On the same training program, women and men gain equal muscle mass relative to their body weight.

Average possible rate of muscle gain:

If you’re a beginner, take this opportunity to train methodically and intensively. You have a year to build a solid foundation.

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