Essential nutrients during weight loss diets: what they are and how to avoid deficiencies
Cuando pensamos en lose weight we usually focus on cutting calories. However, losing weight is not just about eating less, but about ensuring that the body continues to receive all the essential nutrients it needs to function properly.
Una low-calorie diet poorly planned or the use of advanced medical treatments for weight management they can decrease the intake of proteins, vitamins, and minerals. Esto no solo puede afectar a la energía o al bienestar general, sino también dificultar el mantenimiento de la masa muscular, comprometer la función inmunitaria o favorecer la aparición de déficits nutricionales.
"high-quality weight loss, we know that success should not be measured solely by the pounds lost on the scale. The true indicator of metabolic health is to achieve reduce body fat while maximizing muscle mass protection, preserving neuromuscular function and ensuring that micronutrient needs are completely covered. This concept is reflected in the most recent literature and studies on weight loss treatments.
What are essential nutrients?
The essential nutrients are those substances that the body needs to perform vital functions but that it cannot produce on its own (or not in sufficient quantities), meaning they must be obtained through diet.
mmuscle handle immune system.
When the diet is varied and abundant, it is usually possible to meet these needs. However, the more restrictive a diet is (or the more food volume is reduced due to a marked lack of appetite), the more difficult it becomes to reach the minimum daily requirements.
Essential and non-essential nutrients: what is the difference?
The main difference lies in your own body's synthesis capacity. The essential nutrients must be obtained obligatorily through the diet because the body lacks the metabolic pathways to produce them.
Instead, the non-essential nutrients are those that the body can produce autonomously from other compounds already present, meaning their direct consumption is not strictly mandatory under normal conditions.
the term "non-essential" does not detract from the biological importance of a compound. Simplemente significa que, en condiciones de salud óptimas, el cuerpo puede autoabastecerse de él. Sin embargo, en situaciones de alta demanda física, estrés metabólico o dietas hipocalóricas estrictas, la síntesis interna puede quedarse muy corta, transformando algunos de estos nutrientes en "condicionalmente esenciales".
Essential macronutrients and micronutrients: classification
Although we usually think first of the vitamins and minerals when talking about nutrition, during a weight loss diet it is also essential to ensure an adequate intake of proteins and of essential amino acids, ya que participan directamente en el mantenimiento de la masa muscular y ayudan a nuestro cuerpo a producir energía.
Essential nutrients are divided into two major metabolic families:
Macronutrients
These are the ones that the body needs in large daily amounts
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Proteins: Que aportan los bloques de construcción llamados aminoácidos esenciales.
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Fats: Which include essential fatty acids such as omega-3 and omega-6, vital for cell membranes.
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Carbohydrates: Although they are not strictly considered "essential" because the body can synthesize glucose from fats and proteins if necessary.
Micronutrients
They are required in minuscule amounts (milligrams or micrograms), but they are indispensable biological catalysts for life. They include:
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Vitamins: Tanto hidrosolubles (como el grupo B y la C) como liposolubles (A, D, E y K).
These micronutrients act as "cofactors". Sin ellos, las reacciones químicas que nos permiten obtener energía a partir de los alimentos, reparar tus tejidos o mantener activo tu metabolismo, simplemente se detienen.
Why are they key during a weight loss diet?
Reducing calories inevitably implies reducing the total volume of food you put on your plate. If those foods are not selected with precision, the amount of essential nutrients your body receives decreases.
In the field of scientific nutrition, we repeat a maxim: eating less doesn't always mean nourishing yourself better.
Caloric restriction and risk of nutritional deficiencies
The real problem is not just the calorie reduction. When appetite decreases drastically (as typically happens with the new GLP-1 and GIP analog treatments), there is a alteration of food preferencesThey usually develop very early satiety and underlying nausea, which leads them to reject dense and hard-to-digest foods (such as meat, fish, legumes, or fresh vegetables) and take refuge in "comfort foods" rich in refined carbohydrates (white rice, pasta, flours).
the intake of vital micronutrients decreases silently long before obvious clinical symptoms appear.
Nutrients that may be lacking and should be monitored in low-calorie diets
Para comprender la verdadera magnitud de este riesgo, la ciencia nos aporta datos. En un gran estudio clínico (Johnson et al., 2025) que analizó mediante registros dietéticos precisos a pacientes con ingesta reducida por fármacos para adelgazar, se demostraron déficits estadísticamente significativos en nutrientes clave. Asimismo, revisiones científicas de gran escala (Urbina et al., 2026) que incluyeron a casi medio millón de pacientes, documentaron cómo las deficiencias de hierro, vitamina D y vitaminas del grupo B se duplican a los 12 meses de iniciar el proceso de pérdida de peso.
Although it depends on each person and their type of diet, some nutrients present a higher risk of insufficient intake:
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Essential nutrient |
Why can it decrease during a weight loss diet? |
What function does it perform and what does science say? |
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Proteins |
Reduction in total intake, rejection of solid protein foods due to slow digestion |
Preservation of muscle mass. Essential for preventing protein catabolism and keeping the mTOR anabolic pathway active. |
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Colina |
It is the most deficient nutrient (average intake of 305 mg/day compared to the recommended 425-550 mg). Highly lacking due to the rejection of, among other things, eggs. |
Helps prevent metabolic fatty liver disease (present in 70% of people with obesity before losing weight) by allowing fat to be exported as VLDL. |
|
Iron |
Low intake of red meat and active reduction of the intestinal DMT-1 transporter induced by some weight loss drugs. |
Oxygen transport (hemoglobin and myoglobin), thyroid function, and collagen synthesis. Its deficiency doubles the risk of anemia and causes hair loss. |
|
Vitamina D |
Dietary intake provides limited amounts, and during a diet, your intake may cover barely 20% of the recommended amount. |
Contributes to the maintenance of bones, muscle function, and the normal functioning of the immune system. The risk of its deficiency doubles after one year on the diet. |
|
Vitamin K2 |
Absent in common restrictive diets. It is frequently confused with vitamin K1 (associated with blood clotting). |
Activates osteocalcin to bind calcium to the bone and prevent it from going to the arteries. |
|
Vitamina B1 (Tiamina) |
Very limited body reserves (9-18 days) that are rapidly depleted by severe caloric restriction or vomiting. |
Its acute deficiency can lead to extreme fatigue and even Wernicke's encephalopathy. |
|
Vitamina B12 |
It can decrease if the consumption of animal-based foods is reduced, especially in poorly planned vegetarian or vegan diets. |
It is necessary for the formation of red blood cells, the nervous system, and normal energy metabolism. Helps prevent neuropathy and chronic fatigue. |
|
Vitamina C |
Many people reduce their consumption of fruits and vegetables due to early satiety. |
muscle connective tissue recovery. |
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Folic acid (folate) |
By reducing portions of foods such as legumes, leafy green vegetables, or whole grains. Between 40% and 60% of the population has a genetic alteration (in the MTHFR enzyme) that prevents them from activating and absorbing conventional synthetic folic acid. |
(En su forma de Quatrefolic®, se absorbe directamente sin necesidad de transformación biológica). |
|
Vitamin E |
Suboptimal dietary intake (average of 9.6 mg/day compared to the recommended 15 mg) when reducing fats and oils. |
Cell membrane antioxidant. Protects tissues against the high oxidative stress derived from burning fat quickly. |
|
Vitamina A |
Ingesta de 560 mcg/día (por debajo de la recomendada), sumado a una menor absorción de grasas que la transportan. |
Cellular modulator, maintenance of protective mucous membranes, and regulation of immune function. |
This does not mean that everyone who follows highly restrictive diets will develop these deficiencies, but it is advisable pay attention to nutritional planning.
What are the main essential nutrients, then, and what is their function?
energy production maintain muscle mass functioning of the nervous system or contribute to the correct immune system function.
When the diet is varied, it is usually possible to meet your needs through food. However, during a diet of weight loss caloric restriction important or a low food variety, conviene prestar especial atención a aquellos nutrientes cuya ingesta puede reducirse con mayor facilidad.
Essential vitamins and minerals
Las vitaminas y los minerales son micronutrientes esenciales: el organismo los necesita en pequeñas cantidades, pero participan en cientos de procesos fisiológicos imprescindibles para mantener la salud.
especially when entire food groups are eliminated or very low-calorie options are prioritized which also have low nutritional density.
The nutrients most likely to be affected by highly restrictive diets or weight loss treatments were highlighted in the previous section. However, in addition to these, it is important to mention two minerals that are also essential for our body: the magnesium which plays a role in muscle function, energy metabolism, and the normal functioning of the nervous system, and zinc which is involved in protein synthesis, immune function, and skin maintenance.
Essential fatty acids (Omega-3) and essential amino acids
fats and proteins that the body needs to obtain through diet because it cannot synthesize them on its own in sufficient quantities.
Essential fatty acids (Omega-3)
Omega-3 fatty acids are components fundamental components of cell membranes and participate in numerous physiological processes EPA and DHA, presentes principalmente en el pescado azul, mientras que el ALA se encuentra en alimentos vegetales como las nueces o las semillas de lino y chía.
Durante una dieta de pérdida de peso es frecuente reducir el consumo de alimentos ricos en grasas. Sin embargo, esto no debería implicar eliminar las grasas saludables, ya que forman parte de una alimentación equilibrada y contribuyen, entre otras funciones, al mantenimiento de la salud cardiovascular.
Essential amino acids
Proteins are made up of amino acids, but not all of them can be manufactured by the body. There are nueve aminoácidos esenciales that must be obtained through the diet.
protein intake is a decisive factor daily protein intake should be between 1.2 and 1.6 grams per kilo of body weight. However, we must also ensure cellular activation through the mTOR anabolic pathway.
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The myth of leucine alone mandatory to consume complete proteins of high biological value that provide all amino acids essentials together to activate the muscular machinery.
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The golden rule: protein firstAt times when stomach emptying is significantly delayed and appetite is low, solid protein is often instinctively avoided due to heavy digestion, with simple refined carbohydrates being preferred instead. The most effective practical recommendation for daily life is to always consume the protein component at the beginning of the meal, ensuring that the basic requirement is met before early satiety sets in.
Ultimately, maintaining an adequate protein intake during weight loss is especially important for preserve muscle mass, promote tissue recovery, and contribute to a greater feeling of fullness conservar la masa muscular ayuda a mantener el metabolismo activo while reducing adipose tissue.
How to meet your essential nutrient needs while losing weight
Losing weight doesn't simply mean eating less, but learning to make better food choices. A well-planned weight loss diet must provide all the essential nutrients the body needs, even when there is a reduction in calories.
prioritize nutrient-dense foods: aquellos que aportan una gran cantidad de vitaminas, minerales, proteínas y grasas saludables en relación con su contenido energético.
A varied diet even with restrictive diets
the more varied a diet is, the easier it is to meet the needs for essential nutrients.
Highly restrictive diets, which eliminate entire food groups or are based on a very limited number of products, increase the risk of developing nutritional deficiencies over time. For this reason, during weight loss, it is advisable to maintain a consistent eating pattern that includes:
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Vegetables and greens daily.
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Fresh fruit.
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Legumes.
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Whole grains.
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Quality proteins (fish, eggs, lean meats, or plant-based proteins).
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Nuts and seeds.
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Healthy fats, such as extra virgin olive oil or oily fish.
intermittent fasting can be part of a nutritional plan for certain people, as long as the quality of the diet remains appropriate and nutritional needs are met.
When to consider a supportive dietary supplement?
Diet should always be the primary source of nutrients. However, there are situations where it can be difficult to meet all needs solely through diet.
This can occur, for example, during highly restrictive diets, in people with increased nutritional needs, at certain stages of life, or when there are dietary limitations that reduce the consumption of certain food groups.
as long as it is used on an individual basis and not as a substitute for a balanced diet.
comprehensive, responsible, and highly scientifically effective approach, at IVB we structure patient support into several synergistic pillars that act in a coordinated manner.
Pack IVB Essentials Pack Metabolic-Max and SatiSens, que puede formar parte de un abordaje global junto con una dieta equilibrada, ejercicio físico y hábitos de vida saludables.
Additionally, during a weight loss diet, special attention should be paid to protein and fiber content, ya que ambos nutrientes desempeñan un papel importante en la calidad de la pérdida de peso.
When it is difficult to reach the daily protein requirements solely through diet, a high-quality protein can be a very practical supplement to complete your protein intake.
The IVB Proteins are designed to optimize your daily nutrition, maintain and build muscle mass, support your bone health, and promote faster, more effective recovery after exercise. They are proteins of high purity, including only essential ingredients and independent laboratory testing that certify the actual protein content. And, additionally, you have the dairy version but also the vegan one with a unique blend of soy, pea, lupin, and sunflower seed protein, which gives it an amino acid profile comparable to the gold standard of animal-based proteins.
On the other hand, the fiber promotes healthy bowel transit, contributing to greater satiety and helping to maintain a balanced microbiota. However, many people unintentionally reduce their intake by decreasing their total food consumption or by limiting fruits, vegetables, legumes, and whole grains during a diet. In these cases, increasing the presence of fiber-rich foods or considering a supplement such as FiberTotal can be a useful strategy to make food tracking easier and promote good digestive health.
Warning signs of potential nutritional deficiencies
Nutritional deficiencies do not usually appear overnight. In most cases, they develop progressively, and their symptoms can be non-specific, making them not always easy to identify.
The presence of one or more of these symptoms does not in itself confirm the existence of a clinical deficiency, but it does constitute a compelling reason to thoroughly review the quality of your diet and consult with a healthcare professional for an analytical assessment
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Fatigue or a persistent feeling of lack of energy.
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Muscle weakness or decreased physical performance.
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Difficulty concentrating or a feeling of "brain fog."
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Slower recovery after exercise.
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Accelerated hair loss or brittle and fragile nails.
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Increased susceptibility to recurrent infections.
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Skin changes or dryness of the mucous membranes.
Asegurar un aporte adecuado de nutrientes esenciales durante una dieta de pérdida de peso es una de las mejores estrategias sin comprometer la salud.
Essential Nutrients Frequently Asked Questions (FAQ)
What are essential nutrients?
Essential nutrients are those substances that the body needs to function properly and cannot produce on its own (or not in sufficient quantities). Therefore, they must be obtained through diet.
What are the essential nutrients?
The main essential nutrients include vitamins, minerals, essential amino acids, and essential fatty acids. All of them participate in functions as important as energy metabolism, the maintenance of muscle mass, immune function, the nervous system, or bone health.
Can you meet all your essential nutrient needs during a weight loss diet?
Sí. Una dieta de pérdida de peso bien planificada puede aportar todos los nutrientes esenciales que el organismo necesita. La clave está en reducir las calorías sin disminuir la calidad nutricional de la alimentación, priorizando alimentos ricos en proteínas, vitaminas, minerales y grasas saludables.
Do food supplements replace a balanced diet?
No. Food supplements are designed to supplement the diet when there is a specific need, but they do not replace a varied and balanced diet or a healthy lifestyle.
References
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Batsis JA, Gavras A, Gross DC, et al. Effect of incretin-based and nonpharmacologic weight loss on body composition: a systematic review. Ann Intern Med. 2026.
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Deutz NEP, et al. Protein intake and exercise for optimal muscle function with aging: Recommendations from the ESPEN Expert Group. Clinical Nutrition. 2014.
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European Food Safety Authority (EFSA). Dietary Reference Values for nutrients. EFSA Journal. Available at: https://www.efsa.europa.eu/
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Johnson KA, et al. Nutritional implications of GLP-1 receptor agonist therapy. Nutrients. 2025.
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Johnson B, Milstead M, Thomas O, et al. Investigating nutrient intake during use of glucagon-like peptide-1 receptor agonist: a cross-sectional study. Front Nutr. 2025;12:1566498.
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Urbina J, Salinas-Ruiz LE, Valenciano C, Clapp B. Micronutrient and nutritional deficiencies associated with GLP-1 receptor agonist therapy: a narrative review. Clin Obes. 2026;16:e70070.
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World Health Organization (WHO). Healthy diet. World Health Organization; 2024 update. Available at: https://www.who.int/news-room/fact-sheets/detail/healthy-diet