Overweight and obesity: what they really mean and what to review
Let's be clear. Many people hear about overweight and obesity as if it all boiled down to eating less and moving more. Or as if just looking at a number explained everything.
What we really mean by overweight and obesity
The World Health Organisation defines overweight and obesity as an abnormal or excessive accumulation of body fat that may pose a risk to health. This definition already gives us an important clue: we are not just talking about aesthetics or an isolated number, but about a health issue that needs to be properly contextualised.
Simply put, overweight and obesity are not exactly the same. Both can indicate excess body weight, but obesity is associated with a higher risk of complications and usually requires a more careful assessment of each person's clinical context.
How it is assessed and the role of BMI
BMI, or Body Mass Index, is a measure that relates weight to height. In adults, the most used categories are: normal weight between 18.5 and less than 25; overweight between 25 and less than 30; obesity from 30 onwards. It is a useful tool for an initial assessment and for population studies, but by itself, it is not enough to define a person's complete situation.
What BMI does not tell us by itself is that it should be interpreted along with other data, such as body composition, blood pressure, glucose, cholesterol or medical history.
Why they do not only depend on "eating more" or "moving less"
Body weight does not depend on a single cause. Diet and physical activity play a role, of course, but so do the environment, sleep, stress, daily routine, and other biological and social factors. Even official bodies insist that not all risk factors are modifiable in the same way or have the same weight in all people.
What risks should be taken into account without causing alarm
Obesity is associated with an increased risk of several diseases, including type 2 diabetes, cardiovascular disease, stroke, fatty liver disease, and other health problems. Overweight can also increase risk in some contexts, though not in the same way or with the same intensity in all people.
What approach often makes the most sense to address them
In most cases, the approach begins with realistic and sustainable lifestyle changes. Official bodies talk about individualised plans, regular physical activity, balanced diet and long-term follow-up, not shortcuts or quick fixes.
The WHO recommends, for the adult population, at least 150 minutes per week of moderate physical activity or 75 minutes of vigorous activity, in addition to muscle strengthening exercises two or more days per week.
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