<\/p>\n\n\n\n
The goal isn\u2019t to convince you of one \u201ccorrect\u201d approach. The goal is to understand how the body works, so you can make decisions based on facts, not fear or trends.<\/p>\n\n\n\n
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Calories: the foundation you can\u2019t bypass<\/strong><\/h2>\n\n\n\nA calorie is not a diet. A calorie is not the enemy. And it\u2019s definitely not a modern invention. <\/strong>A calorie is simply a unit of energ, specifically, the amount of energy required to raise the temperature of one kilogram of water by one degree Celsius. In nutrition, it\u2019s used to express the energy content of foods and beverages.<\/p>\n\n\n\nIn practice, you\u2019ll encounter two units: kcal and kJ<\/strong>. They represent the same energy, just written differently. The conversion is simple: 1 kcal = 4.18 kJ. From the perspective of weight loss, weight gain, or health, there is no difference between them<\/strong>.<\/p>\n\n\n\nYou can\u2019t trick energy, and you can\u2019t avoid it. You can eat \u201cclean,\u201d you can eat low carb, keto, or intuitively. The body still runs on energy. That\u2019s not a trend. That\u2019s physics.<\/strong><\/p>\n\n\n\nAnd that\u2019s exactly why we need to move beyond calories themselves\u2026 to where that energy actually comes from.<\/p>\n\n\n\n
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Macronutrients and micronutrients: where energy comes from<\/strong><\/h2>\n\n\n\nMacronutrients<\/strong> are the core components of our diet that provide the body with energy. These include proteins, fats, and carbohydrates (along with fiber, which plays a specific role in digestion and satiety). Each of them has a different function and a distinct biological role.<\/p>\n\n\n\nCarbohydrates = the primary source of energy<\/strong><\/p>\n\n\n\nCarbohydrates are classified based on their structure and the speed at which they\u2019re absorbed:<\/p>\n\n\n\n
\n- Monosaccharides<\/strong>: simple sugars (glucose, fructose). Rapidly absorbed and a quick source of energy.<\/li>\n\n\n\n
- Oligosaccharides<\/strong>: a slower source of energy:
- disaccharides (sucrose, lactose, maltose),<\/li><\/ul>
- trisaccharides (e.g., raffinose),<\/li><\/ul>\n
\n- oligosaccharides such as inulin.<\/li>\n<\/ul>\n<\/li>\n\n\n\n
- Polysaccharides<\/strong>: complex carbohydrates (starch, glycogen, pectins, fiber). They\u2019re absorbed slowly, keep you fuller for longer, and form the foundation of long-term energy supply.<\/li>\n<\/ul>\n\n\n\n
Fats = energy storage and hormonal regulation<\/strong><\/p>\n\n\n\nFats in the diet are not \u201cjust extra calories.\u201d They\u2019re essential for hormone production, the nervous system, and the absorption of vitamins A, D, E, and K.<\/p>\n\n\n\n
Basic classification:<\/p>\n\n\n\n
\n- saturated fats <\/strong>(commonly found in animal products and some oils),<\/li>\n\n\n\n
- unsaturated fats<\/strong> (mono- and polyunsaturated = typically found in fish, nuts, and olive oil),<\/li>\n\n\n\n
- trans fats<\/strong> (this is the category you really don\u2019t want to consume often).<\/li>\n<\/ul>\n\n\n\n
Proteins = building material<\/strong><\/p>\n\n\n\nProteins primarily serve to:<\/p>\n\n\n\n
\n- build and repair muscle tissue,<\/li>\n\n\n\n
- form enzymes and hormones,<\/li>\n\n\n\n
- support immune function.<\/li>\n<\/ul>\n\n\n\n
They\u2019re not a primary energy source, but they do have a high thermic effect (see below).<\/p>\n\n\n\n
In practice, proteins are most often categorized by their source and \u201ccompleteness\u201d:<\/p>\n\n\n\n
\n- animal proteins <\/strong>(meat, fish, eggs, dairy): usually considered amino-acid complete,<\/li>\n\n\n\n
- plant proteins <\/strong>(legumes, grains, nuts, seeds): can be perfectly adequate, but often require combining different sources.<\/li>\n<\/ul>\n\n\n\n
<\/p>\n\n\n\n
Micronutrients<\/strong><\/p>\n\n\n\nVitamins, minerals, and trace elements provide little to no energy, but without them the body simply can\u2019t function properly. <\/strong>They affect the nervous system, immunity, recovery, hormones, and metabolic processes.<\/p>\n\n\n\nVitamins are classified by their solubility:<\/p>\n\n\n\n
\n- water-soluble vitamins<\/strong> (B-complex vitamins, vitamin C), which the body generally doesn\u2019t store and therefore need to be consumed regularly,<\/li>\n\n\n\n
- fat-soluble vitamins<\/strong> (A, D, E, K), which are stored in fat tissue and whose absorption depends on the presence of dietary fat.<\/li>\n<\/ul>\n\n\n\n
Minerals<\/strong> and trace elements (such as calcium, magnesium, iron, zinc, iodine, selenium) are essential for proper enzyme activity, hormone function, nervous system signaling, and muscle contraction.<\/p>\n\n\n\nOne doesn\u2019t work without the other. You can have a perfectly calculated calorie intake and an \u201cideal\u201d meal plan, but without adequate micronutrients, the body won\u2019t run efficiently. <\/strong>And on the flip side, even so-called \u201csuperfoods\u201d won\u2019t fix a long-term broken energy balance.<\/p>\n\n\n\n<\/p>\n\n\n\n
Energy value of macronutrients<\/strong><\/p>\n\n\n\nEach macronutrient provides a different amount of energy:<\/p>\n\n\n\n
\n- Carbohydrates:<\/strong> 4 kcal per gram<\/li>\n\n\n\n
- Protein:<\/strong> 4 kcal per gram<\/li>\n\n\n\n
- Fat:<\/strong> 9 kcal per gram<\/li>\n\n\n\n
- Alcohol:<\/strong> 7 kcal per gram (not a macronutrient, but worth mentioning)<\/em><\/li>\n\n\n\n
- Fiber:<\/strong> approximately 2 kcal per gram (depending on type and gut fermentation)<\/em><\/li>\n<\/ul>\n\n\n\n
This difference in energy density is why the same volume of food can have very different calorie content.<\/p>\n\n\n\n
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Energy balance: deficit, surplus, and maintenance<\/strong><\/h2>\n\n\n\nChanges in body weight and body composition are always the result of energy balance.<\/p>\n\n\n\n
An energy<\/strong> deficit<\/strong> occurs when you expend more energy than you consume. The result is weight loss, primarily a loss of body fat.<\/p>\n\n\n\nAn energy<\/strong> surplus<\/strong> means you consume more energy than your body uses. It\u2019s necessary for building muscle mass (assuming proper strength training).<\/p>\n\n\n\nA balanced<\/strong> energy<\/strong> intake means maintaining your current state.<\/p>\n\n\n\nYes, it\u2019s possible to build muscle in a deficit, but mostly in beginners and in people with a higher body fat percentage. In very lean and advanced individuals, this process is significantly limited.<\/p>\n\n\n\n
\ud83d\udc49 If you want to know how many calories to eat for your goal (weight loss \/ weight gain \/ maintenance), check the Target calculator<\/a>.<\/strong><\/p>\n\n\n\nAnd this is where we get to a concept that\u2019s far more important than the number on the scale.<\/p>\n\n\n\n
<\/p>\n\n\n\n
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Body composition: more than just a number on the scale<\/strong><\/h2>\n\n\n\nBody composition reflects the ratio of fat mass to muscle mass. Two people can weigh the same and have completely different health profiles.<\/p>\n\n\n\n
What matters isn\u2019t only how much fat you have, but also where it\u2019s stored.<\/strong><\/p>\n\n\n\nFat stored around the abdomen (visceral fat) is metabolically active and is associated with a higher risk of:<\/p>\n\n\n\n
\n- insulin resistance,<\/li>\n\n\n\n
- type 2 diabetes,<\/li>\n\n\n\n
- cardiovascular disease.<\/li>\n<\/ul>\n\n\n\n
Risk waist circumference values:<\/p>\n\n\n\n
\n- women: over 35 inches (\u2248 89 cm)<\/li>\n\n\n\n
- men: over 40 inches (\u2248 102 cm)<\/li>\n<\/ul>\n\n\n\n
A \u201cnormal\u201d weight does not automatically mean good health.<\/p>\n\n\n\n
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BMR and RMR: the metabolic minimum for life<\/strong><\/h2>\n\n\n\nBMR (Basal Metabolic Rate)<\/strong> represents the amount of energy your body needs to maintain basic \u0436\u0438\u0437\u043d\u0435\u043d\u2026 life-sustaining functions: breathing, heart activity, brain function, liver and kidney function, and thermoregulation. It accounts for roughly 60\u201370% of total daily energy expenditure.<\/p>\n\n\n\nRMR (Resting Metabolic Rate)<\/strong> is a more practical metric for everyday life. In addition to the basic functions covered by BMR, it also includes minor activities at rest and what realistically happens throughout the day.<\/p>\n\n\n\nBMR\/RMR calculations are only estimates, because they don\u2019t account for the exact ratio of muscle mass to fat mass. That\u2019s why they can underestimate energy expenditure in muscular individuals and overestimate it in people with a higher amount of body fat. This is also why two people with the same body weight can have completely different BMR values.<\/p>\n\n\n\n
\ud83d\udc49 Calculate your BMR using our calculator<\/a><\/strong> and treat it as a \u201cmetabolic minimum,\u201d not a personal insult.<\/p>\n\n\n\nYou can read more about BMR in this article: Why a \u201cslow metabolism\u201d or \u201cstarvation mode\u201d is not the problem in weight loss. Metabolism, NEAT, and real differences between people<\/a><\/p>\n\n\n\n<\/p>\n\n\n\n
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TDEE: total daily energy expenditure<\/strong><\/h2>\n\n\n\nTDEE (Total Daily Energy Expenditure)<\/strong> represents the total amount of energy you burn in a day. It\u2019s not a single number, but the sum of several processes:<\/p>\n\n\n\n\n- BMR\/RMR <\/strong>(your metabolic minimum) plus work-related stress,<\/li>\n\n\n\n
- physical activity<\/strong> (intentional movement, e.g. training),<\/li>\n\n\n\n
- NEAT<\/strong> (non-exercise, unintentional movement),<\/li>\n\n\n\n
- TEF<\/strong> (the energy required to process food).<\/li>\n<\/ul>\n\n\n\n
TDEE is a dynamic value. It changes with body weight, behavior, stress levels, sleep, and diet. That\u2019s why it\u2019s an illusion to think that a number calculated once \u201capplies forever.\u201d These values need to be updated regularly.<\/strong><\/p>\n\n\n\nIf you want clarity on where you stand, start by calculating your TDEE. You can use our TDEE calculator for that.<\/a><\/strong><\/p>\n\n\n\n<\/p>\n\n\n\n
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BMI: a simple tool with major limitations<\/strong><\/h2>\n\n\n\nBMI (Body Mass Index)<\/strong> is one of the most commonly used metrics because it\u2019s quick and simple. Advantage: speed. Weakness: reality. It\u2019s used for a quick assessment of body weight relative to height, at least in adults. For children, different reference charts apply.<\/p>\n\n\n\nBMI does not distinguish muscle from fat, nor does it account for age or fat distribution. Research shows that a large proportion of people classified by BMI as having \u201cnormal weight\u201d may actually have a high body fat percentage. On the other hand, in athletes BMI can look \u201cworse\u201d than it really is and than what their health status reflects.<\/p>\n\n\n\n
That\u2019s why BMI is suitable as an orientation or screening tool, not as a precise diagnostic measure.<\/p>\n\n\n\n
BMI calculations often fail especially in older adults. Why? One of the main reasons is sarcopenia<\/strong>.<\/p>\n\n\n\nSarcopenia<\/strong> is the gradual loss of muscle mass, strength, and function that typically accompanies aging, but it can also occur with a sedentary lifestyle and chronic diseases. Key factors in its development include low physical activity and long-term insufficient intake of protein, as well as vitamins and minerals.<\/p>\n\n\n\nThat\u2019s why a person can have a \u201cnormal BMI\u201d while still having low muscle mass and a higher health risk, something BMI simply cannot distinguish.<\/p>\n\n\n\n
\ud83d\udc49 Calculate your BMI using a calculator<\/a>, but treat it as a first estimate, not a verdict.<\/strong><\/p>\n\n\n\nIf you\u2019re interested in more information about BMI, you can find it on our blog in this article: <\/strong>BMI isn\u2019t a rulebook. But do you know when you can actually trust it?<\/a><\/p>\n\n\n\n<\/p>\n\n\n\n
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Hormones: regulators of behavior, not saboteurs<\/strong><\/h2>\n\n\n\nLeptin, ghrelin, cortisol, insulin<\/strong><\/p>\n\n\n\nThey have a major influence on how you feel, what you want to eat, how full you feel, and how much energy you have. But the core rule still applies: they don\u2019t create fat out of thin air.<\/p>\n\n\n\n
Leptin<\/strong> is the satiety signal. When its levels drop (for example during a strict diet or extreme training), the brain gets the message \u201cenergy is low.\u201d The result? More hunger, less satiety, and poorer adherence to the plan.<\/p>\n\n\n\nGhrelin<\/strong> is the hunger hormone. It rises with lack of sleep and prolonged calorie deficits. That\u2019s not sabotage, that\u2019s the body trying to secure energy.<\/p>\n\n\n\nCortisol<\/strong> increases with stress, excessive training volume, lack of sleep, and long-term calorie restriction. Elevated cortisol worsens recovery, promotes water retention, and often increases hunger and fatigue. That\u2019s why people after drastic diets often don\u2019t look \u201cleaner,\u201d but rather exhausted and water-retained.<\/p>\n\n\n\nInsulin: a hormone of life, not an enemy<\/strong>
Insulin<\/strong> is a hormone produced by the pancreas and is essential for life. Its roles are very practical:<\/p>\n\n\n\n\n- it helps transport nutrients into cells,<\/li>\n\n\n\n
- allows the body to use glucose as energy,<\/li>\n\n\n\n
- regulates carbohydrate, fat, and protein metabolism,<\/li>\n\n\n\n
- enables energy storage – but the key word is excess<\/strong>.<\/li>\n<\/ul>\n\n\n\n
Glucose can be used immediately as fuel, or stored as glycogen in the liver and muscles. Muscle glycogen is used mainly during training, while liver glycogen helps maintain stable blood glucose levels.<\/p>\n\n\n\n
Important: insulin doesn\u2019t rise only after carbohydrates. Protein and fat can increase insulin as well (to different degrees and depending on context). That\u2019s why it\u2019s an oversimplification to claim that \u201conly carbs are bad.\u201d<\/strong><\/p>\n\n\n\nAnd even more important: the amount of insulin does not determine how much fat you store. The biggest driver of fat gain is still excess energy intake.<\/p>\n\n\n\n
The takeaway: hormones usually do this, they increase appetite, reduce spontaneous movement, and make adherence harder. They are amplifiers of behavior, not biological saboteurs.<\/strong><\/p>\n\n\n\n<\/p>\n\n\n\n
Refeed: why a short-term calorie increase is not failure<\/strong><\/h3>\n\n\n\nThere\u2019s one often misunderstood fact that goes against the fitness logic of \u201cthe less, the better.\u201d A short-term increase in calorie intake, especially from complex carbohydrates, known as a refeed, can have a positive biological effect.<\/p>\n\n\n\n
A refeed can lower cortisol, temporarily increase leptin signaling, improve energy and performance, and reduce water retention. <\/strong>Importantly, short-term changes in leptin are not directly tied to body fat levels, but rather to how the body perceives energy availability and how glucose is processed in fat cells.<\/p>\n\n\n\nThe problem with extremely long diets without breaks isn\u2019t a \u201cruined metabolism,\u201d but rising stress, poorer recovery, and declining sustainability.<\/strong> Well-designed maintenance phases or refeeds are therefore not a weakness. They are strategic tools. Not a\u00a0hack, just biology in practice.<\/p>\n\n\n\n<\/p>\n\n\n\n
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Insulin resistance (IR): when the body needs more insulin<\/strong><\/h2>\n\n\n\nInsulin sensitivity describes the relationship between how much insulin the body needs to move glucose into cells. The higher the sensitivity, the less insulin is required.<\/p>\n\n\n\n
With insulin resistance, the pancreas must produce more insulin to achieve the same effect. It\u2019s often associated with:<\/p>\n\n\n\n
\n- a higher percentage of body fat,<\/li>\n\n\n\n
- low NEAT,<\/li>\n\n\n\n
- long-term unhealthy lifestyle habits.<\/li>\n<\/ul>\n\n\n\n
In type 2 diabetes, a very common and logical solution is fat loss and lifestyle change, often without the need for extreme low-carb approaches.<\/p>\n\n\n\n
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Glycemic Index (GI) and Glycemic Load (GL): useful for some, but not sacred rules<\/strong><\/h2>\n\n\n\nThe glycemic index (GI)<\/strong> describes how quickly and how strongly a food raises blood glucose levels.<\/p>\n\n\n\nIt is usually categorized as:<\/p>\n\n\n\n
\n- low: 0 – 55<\/li>\n\n\n\n
- medium: 55\u201369<\/li>\n\n\n\n
- high: 70+<\/li>\n<\/ul>\n\n\n\n
Glycemic load (GL)<\/strong> also takes into account the amount of carbohydrates in a serving, making it more practical, because in real life, portion size matters.<\/p>\n\n\n\nGI\/GL can be useful for people with diabetes or insulin resistance, but for a healthy person, they are not a magical \u201chealthy vs. unhealthy\u201d rule. From a weight-loss perspective, energy balance and overall diet quality still matter most, not a GI table.<\/p>\n\n\n\n
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Adaptive thermogenesis and \u201cstarvation mode\u201d<\/strong><\/h2>\n\n\n\nAdaptive thermogenesis is real, but often greatly exaggerated. It means that energy expenditure decreases slightly more than would be expected from weight loss alone.<\/p>\n\n\n\n
Research shows this effect is small, mild, and temporary, and it significantly weakens or disappears entirely once body weight stabilizes. In practice, we\u2019re talking about tens of calories per day, not hundreds.<\/strong><\/p>\n\n\n\nThe body isn\u2019t trying to sabotage weight loss. It\u2019s simply becoming more energy-efficient. That\u2019s not a\u00a0malfunction. It\u2019s a logical adaptation:<\/strong><\/p>\n\n\n\n\n- a smaller body needs less energy<\/strong>,<\/li>\n\n\n\n
- you unconsciously reduce NEAT<\/strong>\u2014less fidgeting, less foot tapping, fewer spontaneous movements,<\/li>\n\n\n\n
- there is a loss of metabolically active tissue\u2014muscle,<\/strong> which also lowers calorie needs.<\/li>\n<\/ul>\n\n\n\n
Everything here follows a clear logic, and there\u2019s no need to panic about it.<\/p>\n\n\n\n
In practice, you\u2019ll encounter two units: kcal and kJ<\/strong>. They represent the same energy, just written differently. The conversion is simple: 1 kcal = 4.18 kJ. From the perspective of weight loss, weight gain, or health, there is no difference between them<\/strong>.<\/p>\n\n\n\n You can\u2019t trick energy, and you can\u2019t avoid it. You can eat \u201cclean,\u201d you can eat low carb, keto, or intuitively. The body still runs on energy. That\u2019s not a trend. That\u2019s physics.<\/strong><\/p>\n\n\n\n And that\u2019s exactly why we need to move beyond calories themselves\u2026 to where that energy actually comes from.<\/p>\n\n\n\n <\/p>\n\n\n\n <\/p>\n\n\n\n Macronutrients<\/strong> are the core components of our diet that provide the body with energy. These include proteins, fats, and carbohydrates (along with fiber, which plays a specific role in digestion and satiety). Each of them has a different function and a distinct biological role.<\/p>\n\n\n\n Carbohydrates = the primary source of energy<\/strong><\/p>\n\n\n\n Carbohydrates are classified based on their structure and the speed at which they\u2019re absorbed:<\/p>\n\n\n\n Fats = energy storage and hormonal regulation<\/strong><\/p>\n\n\n\n Fats in the diet are not \u201cjust extra calories.\u201d They\u2019re essential for hormone production, the nervous system, and the absorption of vitamins A, D, E, and K.<\/p>\n\n\n\n Basic classification:<\/p>\n\n\n\n Proteins = building material<\/strong><\/p>\n\n\n\n Proteins primarily serve to:<\/p>\n\n\n\n They\u2019re not a primary energy source, but they do have a high thermic effect (see below).<\/p>\n\n\n\n In practice, proteins are most often categorized by their source and \u201ccompleteness\u201d:<\/p>\n\n\n\n <\/p>\n\n\n\n Micronutrients<\/strong><\/p>\n\n\n\n Vitamins, minerals, and trace elements provide little to no energy, but without them the body simply can\u2019t function properly. <\/strong>They affect the nervous system, immunity, recovery, hormones, and metabolic processes.<\/p>\n\n\n\n Vitamins are classified by their solubility:<\/p>\n\n\n\n Minerals<\/strong> and trace elements (such as calcium, magnesium, iron, zinc, iodine, selenium) are essential for proper enzyme activity, hormone function, nervous system signaling, and muscle contraction.<\/p>\n\n\n\n One doesn\u2019t work without the other. You can have a perfectly calculated calorie intake and an \u201cideal\u201d meal plan, but without adequate micronutrients, the body won\u2019t run efficiently. <\/strong>And on the flip side, even so-called \u201csuperfoods\u201d won\u2019t fix a long-term broken energy balance.<\/p>\n\n\n\n <\/p>\n\n\n\n Energy value of macronutrients<\/strong><\/p>\n\n\n\n Each macronutrient provides a different amount of energy:<\/p>\n\n\n\n This difference in energy density is why the same volume of food can have very different calorie content.<\/p>\n\n\n\n <\/p>\n\n\n\n <\/p>\n\n\n\n Changes in body weight and body composition are always the result of energy balance.<\/p>\n\n\n\n An energy<\/strong> deficit<\/strong> occurs when you expend more energy than you consume. The result is weight loss, primarily a loss of body fat.<\/p>\n\n\n\n An energy<\/strong> surplus<\/strong> means you consume more energy than your body uses. It\u2019s necessary for building muscle mass (assuming proper strength training).<\/p>\n\n\n\n A balanced<\/strong> energy<\/strong> intake means maintaining your current state.<\/p>\n\n\n\n Yes, it\u2019s possible to build muscle in a deficit, but mostly in beginners and in people with a higher body fat percentage. In very lean and advanced individuals, this process is significantly limited.<\/p>\n\n\n\n \ud83d\udc49 If you want to know how many calories to eat for your goal (weight loss \/ weight gain \/ maintenance), check the Target calculator<\/a>.<\/strong><\/p>\n\n\n\n And this is where we get to a concept that\u2019s far more important than the number on the scale.<\/p>\n\n\n\n <\/p>\n\n\n\n <\/p>\n\n\n\n Body composition reflects the ratio of fat mass to muscle mass. Two people can weigh the same and have completely different health profiles.<\/p>\n\n\n\n What matters isn\u2019t only how much fat you have, but also where it\u2019s stored.<\/strong><\/p>\n\n\n\n Fat stored around the abdomen (visceral fat) is metabolically active and is associated with a higher risk of:<\/p>\n\n\n\n Risk waist circumference values:<\/p>\n\n\n\n A \u201cnormal\u201d weight does not automatically mean good health.<\/p>\n\n\n\n <\/p>\n\n\n\n <\/p>\n\n\n\n BMR (Basal Metabolic Rate)<\/strong> represents the amount of energy your body needs to maintain basic \u0436\u0438\u0437\u043d\u0435\u043d\u2026 life-sustaining functions: breathing, heart activity, brain function, liver and kidney function, and thermoregulation. It accounts for roughly 60\u201370% of total daily energy expenditure.<\/p>\n\n\n\n RMR (Resting Metabolic Rate)<\/strong> is a more practical metric for everyday life. In addition to the basic functions covered by BMR, it also includes minor activities at rest and what realistically happens throughout the day.<\/p>\n\n\n\n BMR\/RMR calculations are only estimates, because they don\u2019t account for the exact ratio of muscle mass to fat mass. That\u2019s why they can underestimate energy expenditure in muscular individuals and overestimate it in people with a higher amount of body fat. This is also why two people with the same body weight can have completely different BMR values.<\/p>\n\n\n\n \ud83d\udc49 Calculate your BMR using our calculator<\/a><\/strong> and treat it as a \u201cmetabolic minimum,\u201d not a personal insult.<\/p>\n\n\n\n You can read more about BMR in this article: Why a \u201cslow metabolism\u201d or \u201cstarvation mode\u201d is not the problem in weight loss. Metabolism, NEAT, and real differences between people<\/a><\/p>\n\n\n\n <\/p>\n\n\n\n <\/p>\n\n\n\n TDEE (Total Daily Energy Expenditure)<\/strong> represents the total amount of energy you burn in a day. It\u2019s not a single number, but the sum of several processes:<\/p>\n\n\n\n TDEE is a dynamic value. It changes with body weight, behavior, stress levels, sleep, and diet. That\u2019s why it\u2019s an illusion to think that a number calculated once \u201capplies forever.\u201d These values need to be updated regularly.<\/strong><\/p>\n\n\n\n If you want clarity on where you stand, start by calculating your TDEE. You can use our TDEE calculator for that.<\/a><\/strong><\/p>\n\n\n\n <\/p>\n\n\n\n <\/p>\n\n\n\n BMI (Body Mass Index)<\/strong> is one of the most commonly used metrics because it\u2019s quick and simple. Advantage: speed. Weakness: reality. It\u2019s used for a quick assessment of body weight relative to height, at least in adults. For children, different reference charts apply.<\/p>\n\n\n\n BMI does not distinguish muscle from fat, nor does it account for age or fat distribution. Research shows that a large proportion of people classified by BMI as having \u201cnormal weight\u201d may actually have a high body fat percentage. On the other hand, in athletes BMI can look \u201cworse\u201d than it really is and than what their health status reflects.<\/p>\n\n\n\n That\u2019s why BMI is suitable as an orientation or screening tool, not as a precise diagnostic measure.<\/p>\n\n\n\n BMI calculations often fail especially in older adults. Why? One of the main reasons is sarcopenia<\/strong>.<\/p>\n\n\n\n Sarcopenia<\/strong> is the gradual loss of muscle mass, strength, and function that typically accompanies aging, but it can also occur with a sedentary lifestyle and chronic diseases. Key factors in its development include low physical activity and long-term insufficient intake of protein, as well as vitamins and minerals.<\/p>\n\n\n\n That\u2019s why a person can have a \u201cnormal BMI\u201d while still having low muscle mass and a higher health risk, something BMI simply cannot distinguish.<\/p>\n\n\n\n \ud83d\udc49 Calculate your BMI using a calculator<\/a>, but treat it as a first estimate, not a verdict.<\/strong><\/p>\n\n\n\n If you\u2019re interested in more information about BMI, you can find it on our blog in this article: <\/strong>BMI isn\u2019t a rulebook. But do you know when you can actually trust it?<\/a><\/p>\n\n\n\n <\/p>\n\n\n\n <\/p>\n\n\n\n Leptin, ghrelin, cortisol, insulin<\/strong><\/p>\n\n\n\n They have a major influence on how you feel, what you want to eat, how full you feel, and how much energy you have. But the core rule still applies: they don\u2019t create fat out of thin air.<\/p>\n\n\n\n Leptin<\/strong> is the satiety signal. When its levels drop (for example during a strict diet or extreme training), the brain gets the message \u201cenergy is low.\u201d The result? More hunger, less satiety, and poorer adherence to the plan.<\/p>\n\n\n\n Ghrelin<\/strong> is the hunger hormone. It rises with lack of sleep and prolonged calorie deficits. That\u2019s not sabotage, that\u2019s the body trying to secure energy.<\/p>\n\n\n\n Cortisol<\/strong> increases with stress, excessive training volume, lack of sleep, and long-term calorie restriction. Elevated cortisol worsens recovery, promotes water retention, and often increases hunger and fatigue. That\u2019s why people after drastic diets often don\u2019t look \u201cleaner,\u201d but rather exhausted and water-retained.<\/p>\n\n\n\n Insulin: a hormone of life, not an enemy<\/strong> Glucose can be used immediately as fuel, or stored as glycogen in the liver and muscles. Muscle glycogen is used mainly during training, while liver glycogen helps maintain stable blood glucose levels.<\/p>\n\n\n\n Important: insulin doesn\u2019t rise only after carbohydrates. Protein and fat can increase insulin as well (to different degrees and depending on context). That\u2019s why it\u2019s an oversimplification to claim that \u201conly carbs are bad.\u201d<\/strong><\/p>\n\n\n\n And even more important: the amount of insulin does not determine how much fat you store. The biggest driver of fat gain is still excess energy intake.<\/p>\n\n\n\n The takeaway: hormones usually do this, they increase appetite, reduce spontaneous movement, and make adherence harder. They are amplifiers of behavior, not biological saboteurs.<\/strong><\/p>\n\n\n\n <\/p>\n\n\n\n There\u2019s one often misunderstood fact that goes against the fitness logic of \u201cthe less, the better.\u201d A short-term increase in calorie intake, especially from complex carbohydrates, known as a refeed, can have a positive biological effect.<\/p>\n\n\n\n A refeed can lower cortisol, temporarily increase leptin signaling, improve energy and performance, and reduce water retention. <\/strong>Importantly, short-term changes in leptin are not directly tied to body fat levels, but rather to how the body perceives energy availability and how glucose is processed in fat cells.<\/p>\n\n\n\n The problem with extremely long diets without breaks isn\u2019t a \u201cruined metabolism,\u201d but rising stress, poorer recovery, and declining sustainability.<\/strong> Well-designed maintenance phases or refeeds are therefore not a weakness. They are strategic tools. Not a\u00a0hack, just biology in practice.<\/p>\n\n\n\n <\/p>\n\n\n\n <\/p>\n\n\n\n Insulin sensitivity describes the relationship between how much insulin the body needs to move glucose into cells. The higher the sensitivity, the less insulin is required.<\/p>\n\n\n\n With insulin resistance, the pancreas must produce more insulin to achieve the same effect. It\u2019s often associated with:<\/p>\n\n\n\n In type 2 diabetes, a very common and logical solution is fat loss and lifestyle change, often without the need for extreme low-carb approaches.<\/p>\n\n\n\n <\/p>\n\n\n\n <\/p>\n\n\n\n The glycemic index (GI)<\/strong> describes how quickly and how strongly a food raises blood glucose levels.<\/p>\n\n\n\n It is usually categorized as:<\/p>\n\n\n\n Glycemic load (GL)<\/strong> also takes into account the amount of carbohydrates in a serving, making it more practical, because in real life, portion size matters.<\/p>\n\n\n\n GI\/GL can be useful for people with diabetes or insulin resistance, but for a healthy person, they are not a magical \u201chealthy vs. unhealthy\u201d rule. From a weight-loss perspective, energy balance and overall diet quality still matter most, not a GI table.<\/p>\n\n\n\n <\/p>\n\n\n\n <\/p>\n\n\n\n Adaptive thermogenesis is real, but often greatly exaggerated. It means that energy expenditure decreases slightly more than would be expected from weight loss alone.<\/p>\n\n\n\n Research shows this effect is small, mild, and temporary, and it significantly weakens or disappears entirely once body weight stabilizes. In practice, we\u2019re talking about tens of calories per day, not hundreds.<\/strong><\/p>\n\n\n\n The body isn\u2019t trying to sabotage weight loss. It\u2019s simply becoming more energy-efficient. That\u2019s not a\u00a0malfunction. It\u2019s a logical adaptation:<\/strong><\/p>\n\n\n\n Everything here follows a clear logic, and there\u2019s no need to panic about it.<\/p>\n\n\n\nMacronutrients and micronutrients: where energy comes from<\/strong><\/h2>\n\n\n\n
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Energy balance: deficit, surplus, and maintenance<\/strong><\/h2>\n\n\n\n
Body composition: more than just a number on the scale<\/strong><\/h2>\n\n\n\n
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BMR and RMR: the metabolic minimum for life<\/strong><\/h2>\n\n\n\n
TDEE: total daily energy expenditure<\/strong><\/h2>\n\n\n\n
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BMI: a simple tool with major limitations<\/strong><\/h2>\n\n\n\n
Hormones: regulators of behavior, not saboteurs<\/strong><\/h2>\n\n\n\n
Insulin<\/strong> is a hormone produced by the pancreas and is essential for life. Its roles are very practical:<\/p>\n\n\n\n\n
Refeed: why a short-term calorie increase is not failure<\/strong><\/h3>\n\n\n\n
Insulin resistance (IR): when the body needs more insulin<\/strong><\/h2>\n\n\n\n
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Glycemic Index (GI) and Glycemic Load (GL): useful for some, but not sacred rules<\/strong><\/h2>\n\n\n\n
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Adaptive thermogenesis and \u201cstarvation mode\u201d<\/strong><\/h2>\n\n\n\n
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