Where the fat sits matters as much as how much you have
En la Universidad de Navarra, investigadores han descubierto que la grasa abdominal subcutánea, medida con ultrasonido justo sobre el ombligo, puede revelar riesgos metabólicos que el peso y el índice de masa corporal no logran capturar. Esta pequeña medición —1,8 centímetros de grosor como umbral— abre una ventana hacia el interior del cuerpo, donde la distribución de la grasa cuenta una historia más honesta que la báscula. En un país donde casi seis millones de personas viven con diabetes, la posibilidad de detectar el riesgo antes de que se convierta en enfermedad representa una de esas oportunidades silenciosas que pueden cambiar muchas vidas.
- La diabetes tipo 2 avanza en silencio: millones de personas se encuentran en fase prediabética sin saberlo, perdiendo la ventana en la que aún es posible revertir el curso.
- El IMC y el peso corporal han dominado la conversación clínica durante décadas, pero son herramientas incompletas que ignoran dónde se acumula realmente la grasa y qué daño metabólico está causando.
- Un ultrasonido sencillo, sin radiación ni agujas, puede medir el grosor de la grasa subcutánea abdominal y revelar marcadores de riesgo —presión arterial elevada, insulina, triglicéridos— que anticipan la enfermedad.
- El umbral de 1,8 cm sobre el ombligo emerge como señal de alerta: quienes lo superan muestran perfiles metabólicos significativamente más deteriorados y tasas más altas de prediabetes y diabetes.
- La investigación aún necesita estudios longitudinales más amplios, pero la dirección es clara: la atención primaria podría adoptar esta herramienta para identificar el riesgo mucho antes de que el daño sea irreversible.
Investigadores del departamento de endocrinología de la Universidad de Navarra han identificado una medición sorprendentemente sencilla que podría transformar la detección temprana de la diabetes: el grosor de la grasa subcutánea situada justo encima del ombligo. Usando ultrasonido —sin radiación ni procedimientos invasivos— analizaron a 103 adultos y concluyeron que el lugar donde se acumula la grasa importa tanto como la cantidad total.
El hallazgo central es preciso: cuando el grosor de esa grasa supera los 1,8 centímetros, medidos entre uno y dos centímetros por encima del ombligo, los pacientes presentan niveles significativamente más altos de presión arterial, insulina, triglicéridos y creatinina. Más revelador aún, este grupo mostró tasas notablemente mayores de prediabetes y diabetes. La doctora Carolina Perdomo, endocrinóloga del centro, lo explica con claridad: es necesario ver dónde está sentada realmente la grasa, algo que una báscula nunca puede mostrar.
Las implicaciones son considerables. Si esta prueba se incorporara a las visitas rutinarias de atención primaria, los médicos podrían identificar a personas en riesgo metabólico mucho antes de que desarrollen una enfermedad establecida. En España, cerca de seis millones de personas viven con diabetes, y entre el 80 y el 90 por ciento corresponden al tipo 2, que altera la regulación de la glucosa y eleva el riesgo cardiovascular. Actuar en la fase prediabética, cuando la intervención aún puede revertir el curso, podría cambiar el desenlace de muchos de esos casos.
El equipo investigador trabaja ya en estudios más amplios y prolongados para confirmar estos resultados. Pero la pregunta que subyace es tan clínica como social: ¿adoptarán las consultas esta herramienta con la rapidez suficiente para que su potencial se traduzca en vidas transformadas?
Researchers at the University of Navarra's endocrinology department have identified a simple measurement that could help catch diabetes risk before it becomes a problem: the thickness of fat sitting just above your navel. Using ultrasound—no radiation, no needles—they measured subcutaneous abdominal fat in 103 adults and found that where fat accumulates matters as much as how much you have.
The distinction is crucial. Weight and BMI tell only part of the story. A person can have excess body fat distributed in ways that pose little metabolic threat, or concentrated in patterns that signal serious trouble ahead. Dr. Carolina Perdomo, an endocrinologist at the clinic, explains the insight plainly: you need to see where the fat is actually sitting. The ultrasound reveals this distribution in ways that a scale never can.
The study's key finding emerged from a specific measurement: patients whose subcutaneous fat thickness exceeded 1.8 centimeters—measured one to two centimeters above the navel—showed significantly elevated blood pressure, insulin levels, triglycerides, and creatinine. These markers paint a picture of metabolic dysfunction. More striking still, those with thicker subcutaneous fat layers above the navel had substantially higher rates of prediabetes and diabetes.
The implications ripple outward. If this simple ultrasound test could be incorporated into routine primary care visits, doctors could identify people at metabolic risk long before they develop full-blown disease. The test is quick, accessible, and requires no special preparation. It shifts the conversation away from the bathroom scale toward something more revealing: the actual metabolic health hiding beneath the skin.
Dr. Perdomo emphasizes that the research team is expanding their work, conducting larger studies over longer periods to confirm these early findings. But the direction is clear. In Spain alone, nearly six million people live with diabetes, with type 2 accounting for 80 to 90 percent of cases. Type 2 diabetes disrupts the body's glucose regulation, raising the risk of heart disease and stroke. Early detection—catching people in the prediabetic stage when intervention can still reverse course—could reshape how many of those cases unfold.
The abdominal ultrasound represents a small shift in clinical practice, but one with outsized potential. It acknowledges what doctors increasingly understand: obesity is not a simple problem of excess weight, but a complex distribution of metabolic risk. Some fat is more dangerous than other fat. The question is whether clinics will adopt the tool quickly enough to matter.
Notable Quotes
We cannot limit ourselves to weight and BMI alone. With this test we can see where the fat accumulates.— Dr. Carolina Perdomo, endocrinologist at Clínica Universidad de Navarra
This simple test could help identify people with metabolic alterations or at higher risk of developing them, opening the possibility of early detection in primary care and other specialties.— Dr. Carolina Perdomo
The Hearth Conversation Another angle on the story
Why does it matter where the fat is, exactly? Isn't fat just fat?
Not metabolically. Fat near your organs behaves differently than fat under the skin. The subcutaneous fat above the navel seems to signal broader metabolic dysfunction—higher insulin, worse blood pressure, more triglycerides. It's like a warning light.
So this ultrasound is better than just weighing someone?
Completely different information. Weight tells you quantity. This ultrasound tells you distribution and quality. Two people at the same weight can have very different metabolic profiles depending on where their fat sits.
How many people did they study?
103 adults, all scanned by the same doctor to eliminate measurement variation. It's a solid foundation, but they're running larger studies now to confirm the pattern holds.
What's the threshold they found?
1.8 centimeters of subcutaneous fat above the navel. Above that, the metabolic markers start looking worse. Below it, people tend to have better profiles.
Could this actually change how doctors screen for diabetes?
That's the hope. If it becomes routine in primary care, you could catch prediabetes early, when lifestyle changes might prevent progression. Right now, many people don't know they're at risk until they're already diabetic.
What's the catch?
The research is still early. They need to prove this works in larger, longer-term studies. But the signal is strong enough that some clinics are already thinking about adding it to their toolkit.