Monarka Clinic · Metabolism Unit
Indirect calorimetry in Barcelona: your metabolism, measured. Not estimated.
We have moved away from relying on formulas to calculate what can now be precisely measured via indirect calorimetry. Understanding how your body produces and expends energy is the starting point for any genuine plan focused on health, performance, and longevity.
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Goals: weight control, performance, energy, and longevity.
100%
measured directly, never calculated using a formula
360°
metabolism, nutrition, and performance in a single report
Why it matters
Almost all guidelines are based on an estimated figure.
Most diets and training plans are based on a formula: an equation that estimates how many calories you burn and where your body gets its energy. The problem is that these formulas frequently fail, sometimes by huge margins. Two people of the same weight and age can have metabolisms that differ by hundreds of kilocalories a day.
When the starting point is incorrect, everything that follows—the deficit, the surplus, macronutrient distribution, training zones—inherits that error. And in the consultation room, that error takes on a very real, tangible form.
Then there are those who eat little yet fail to lose weight: if the formula overestimates their energy expenditure, they are prescribed a “deficit” that isn’t actually one; their body adapts by further lowering energy consumption, and the scale doesn’t budge no matter how hard they try. And then there are those who train hard yet see no improvement: if no one has measured the intensity at which their body stops burning fat and starts accumulating fatigue, they almost always train in the wrong zone—too hard for recovery, too easy for progress—and build up exhaustion without seeing results. In both cases, the problem isn’t a lack of willpower; it’s that they were working based on a figure that was never right for them.
What isn’t measured is estimated. And what is estimated is almost always wrong.
At the Metabolism Unit, we don’t calculate—we measure. We analyze your energy expenditure at rest and during exertion using calorimetry to understand exactly how your body functions before making any recommendations.
What it is used for
What is this test done for?
Metabolic assessment is not an end in itself; it is the foundation upon which any sensible decision regarding your body is built. Knowing exactly how much energy you expend—and where it comes from—answers questions that most plans merely guess at.
Lose fat without punishing yourself
Once we know your actual energy expenditure, the deficit is tailored to your physiology. Say goodbye to the "I eat very little but don't lose weight" scenario: you eat what you need to lose fat sustainably, not what a chart dictates.
Restore energy and perform better
Fatigue, a plateau, or poor performance often has a measurable metabolic cause. We assess how well your body utilizes fat and determine your true limits so you can train intelligently.
Train in your actual zones.
Using your thresholds and VO₂max, we define the exact intensities for each goal—whether you are an athlete or simply looking to take care of your health. No borrowed zones or generic heart rate monitors.
Taking care of your health and longevity
Cardiorespiratory fitness (VO₂max) and metabolic flexibility are among the best predictors of a long, healthy life. Measuring them today allows you to work on improving them and track your progress.
In short: this test allows you to stop working in the dark. Whether your goal is to lose weight, boost performance, regain energy, or invest in longevity, the first step is the same—understanding how your metabolism works before making any changes.
The assessment
Indirect calorimetry: a comprehensive metabolic assessment
We analyze the gases in your breath—the oxygen you consume and the carbon dioxide you produce, breath by breath—to reconstruct your metabolic profile using real data. Indirect calorimetry is a clinical gold-standard measurement, and the assessment is conducted in two phases.
Cortex MetaLyzer 3B. The system analyzes your breathing in real time—VO₂, VCO₂, and RER—to calculate your energy expenditure and substrate utilization with clinical precision.
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Resting indirect calorimetry
We measure your basal metabolism—the energy your body consumes at rest to stay alive—and the proportion derived from fats and carbohydrates.
- Actual resting metabolic rate (RMR), not estimated by formula.
- Substrate oxidation: how much fat and sugar you burn at rest.
- Respiratory quotient and metabolic flexibility.
Resting measurement
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Exercise stress test with ergospirometry
A progressive test on a treadmill or stationary bike while we analyze your breathing. We observe how your body responds to exercise and determine your true limits.
- VO₂max: your maximum aerobic capacity, a key marker of health and longevity.
- Ventilatory thresholds: the exact intensity where your metabolism changes.
- Personalized training zones and fat utilization during exertion.
Exercise testing
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Clinical interpretation and integrated report
Data alone changes nothing. Our team interprets it and turns it into a concrete nutrition and activity plan, with a single report that brings it all together.
- Medical interpretation of your metabolic and performance metrics.
- Nutritional plan calibrated to your actual energy expenditure, by Dr. Ibáñez and Miguel Ducros.
- Physical activity plan based on your actual training zones.
Exercise testing
What you take away
Data that turns into decisions
Your actual basal metabolic rate
How many calories you actually burn at rest—the foundation of any weight, performance, or body composition plan.
Your substrate profile
Whether your body relies more on fat or sugar—at rest and during exercise—and how to improve your metabolic flexibility.
Your VO₂max and thresholds
Your cardiorespiratory capacity and the exact training intensities for each goal.
Nutrition and training plan
A personalized plan built on your measured figures, not on a generic chart.
Why Monarka
What makes us different
Measure, don't assume.
We work with your directly measured metabolism, not with an estimate based on a formula.
Rest and exertion
Two objective tests that provide the full picture: how you expend energy while stationary and in motion.
Longevity approach
VO₂max and metabolic health are among the best predictors of a long, healthy life.
Specialized team
Metabolic medicine and nutrition working together on the same data.
A single report
Everything integrated into a clear document, with conclusions and actionable guidelines.
True personalization
Your plan is tailored to your specific physiology and evolves with you over time.
The team
Who interprets your data
Dr. Iván Ibáñez
Metabolic and Longevity Medicine
A physician specializing in metabolism, weight management, and longevity, and a leading authority on clinical calorimetry. He is the creator of the Metabolic Method® (Método Metabólico®), a system that measures each individual’s metabolism before prescribing any treatment.
- Data-driven approach, not generic formulas
- Expert in calorimetry and metabolic assessment
- Longevity medicine and body composition
Miguel Ducros
Clinical nutrition
A nutritionist focused on sustainable habits and translating science into real-life application. Turn your metabolic data into a concrete, realistic nutrition plan tailored to your daily routine and goals.
- Nutritional plan calibrated to your actual energy expenditure.
- Practical and sustainable long-term approach
- Nutrition education and support
Frequently Asked Questions
What you often wonder
How does indirect calorimetry differ from a scale or a genetic test?
A bioimpedance scale estimates your body composition, and a genetic test indicates predispositions. Indirect calorimetry directly measures how your body is consuming energy right now, breath by breath. It provides functional, real-time data—not an estimate or a probability.
Do I need to be an athlete for the stress test?
No. The test is progressive and adapts to your level. It is suitable for those looking to improve their health and longevity, as well as those seeking to enhance performance. Knowing your VO₂max and thresholds is beneficial regardless of age or fitness level.
How should I prepare for the assessment?
Resting calorimetry is performed while fasting—or after several hours without eating—and in a calm state. For the stress test, prior rest and comfortable clothing are recommended. We will provide exact instructions when you book your appointment.
What do I take away from the indirect calorimetry session?
A report integrating your resting metabolism, fat and sugar utilization profile, cardiorespiratory capacity, and thresholds, along with a nutrition and activity plan based on that data, developed by Dr. Ibáñez and Miguel Ducros.
Stop estimating your metabolism. Start measuring it.
Book your comprehensive metabolic assessment and discover how your body really works.