{"id":173445,"date":"2026-05-28T16:07:54","date_gmt":"2026-05-28T22:07:54","guid":{"rendered":"https:\/\/tecscience.tec.mx\/en\/?p=173445"},"modified":"2026-06-01T10:28:28","modified_gmt":"2026-06-01T16:28:28","slug":"why-bmi-fails-metabolic-health","status":"publish","type":"post","link":"https:\/\/tecscience.tec.mx\/en\/health\/why-bmi-fails-metabolic-health\/","title":{"rendered":"Why BMI fails to measure true metabolic health"},"content":{"rendered":"\n

Picture two patients. The first arrives at the clinic with a Body Mass Index (BMI)<\/a> of 33 (clinically obese) but with normal triglycerides, glucose levels, and blood pressure. The second is a lean 38-year-old presenting with diabetes, fatty liver disease, and a history of heart attacks.\u00a0<\/p>\n\n\n\n

Antonio Vidal-Puig<\/a>, professor of molecular nutrition and metabolism at the University of Cambridge, used these two cases to illustrate the current problem in how we treat obesity during his conference at the International Congress on Obesity Research<\/a> in the Institute for Obesity Research (IOR)<\/a> of Tec de Monterrey.\u00a0<\/p>\n\n\n\n

His research has found that weight or BMI are poor measurements of metabolic health because they fail to capture metabolic flexibility, one of the earliest signs of metabolic dysfunction. <\/strong>\u201cToday\u2019s BMI is not a good indicator of metabolic risk,\u201d said Vidal-Puig. \u201cYou need to look at more functional aspects that go beyond waist circumference.\u201d\u00a0<\/p>\n\n\n\n

The doctor has spent years studying how fat is stored in the body. During his conference, he explained that the process begins in adipose tissue, which has the ability to expand to accommodate more fat. When this organ reaches its limit, lipids start migrating to other organs like the liver, heart, or pancreas, often with serious and irreversible consequences.\u00a0<\/p>\n\n\n\n

How much fat the body can store is largely dictated by genetics and varies from person to person. \u201cNot everyone can become obese even if they tried,\u201d he said during his talk. \u201cThere\u2019s a limit, and when you reach it, you\u2019re becoming metabolically very unwell.\u201d\u00a0<\/p>\n\n\n\n

But it\u2019s not just about how much fat they store or where, but something much harder to measure: the body\u2019s ability to adapt. This is called metabolic flexibility, and, according to Vidal-Puig, its deterioration is the first sign that something is wrong, appearing well before a conventional diagnosis could catch it.<\/p>\n\n\n\n

\r\n \r\n \"\"\r\n <\/picture>
The researcher during his conference at Tecnol\u00f3gico de Monterrey\u2019s Monterrey Campus. (Photo: Everth Ba\u00f1uelos \/ TecScience)<\/figcaption><\/figure>\n\n\n\n

Why BMI is a poor predictor of metabolic health<\/strong><\/h2>\n\n\n\n

Metabolic flexibility is the body\u2019s ability to efficiently alternate between burning fat and burning sugar, depending on what\u2019s available. In evolutionary terms, this fluctuation allowed humans to survive in different environments. A metabolically flexible body can use the resources that are available. An inflexible one gets stuck using the same fuel, regardless of what their needs might be at that moment. <\/p>\n\n\n\n

In a healthy person, that flexibility oscillates constantly throughout the day. After a meal, the metabolism starts burning carbohydrates. At night, with no food coming in, it switches to burning fat. In an obese patient, that oscillation slows down. <\/p>\n\n\n\n

\u201cAt night, they don\u2019t register that it should be burning lipids, so they can\u2019t use them correctly,\u201d said Vidal-Puig in an interview with TecScience. \u201cDuring the day, when they\u2019re eating, they also can\u2019t process carbohydrates efficiently.\u201d <\/p>\n\n\n\n

This doesn\u2019t always lead to visible symptoms, which is why his team is developing tools to detect metabolic risk before any outward signs of disease appear.<\/p>\n\n\n\n

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