A case to start the conversation

Let's call this patient Marisa, 52 years old, a teacher, married, two children. She arrives at the clinic with a simple complaint: "I can't lose weight like I used to". On assessment, the picture is more complex than she imagined:

  • BMI of 34 kg/m² (grade 1 obesity)
  • Waist circumference of 102 cm - a sign of fat concentrated in the abdominal region
  • Slightly elevated blood pressure (140x90 mmHg)
  • Altered cholesterol, with triglycerides above ideal levels
  • Family history of heart attack (her father had one at age 58)
  • Frequent tiredness and a feeling of breathlessness when climbing stairs, which she always attributed to "age" or "sedentary lifestyle"

Marisa is a very common example. She has no diagnosed diabetes, has had no cardiac event to date, and therefore many people, including herself, do not see obesity as a "serious" problem. But when we put all this data together, the picture changes: Marisa falls into what is now called moderate cardiovascular risk, and this completely changes the way obesity treatment should be conducted with her.

It is precisely this type of situation that is becoming increasingly common in clinics, which motivated an important update in the way Brazilian physicians are being guided to treat obesity: not just "by weight", but by the risk that weight represents for the heart.

"The data and clinical case cited in this article are fictional and are purely illustrative, serving to facilitate understanding of the topic covered."

Obesity is not just about the scales

For a long time, obesity treatment revolved around a single number: BMI (Body Mass Index). However, specialists now understand that this is insufficient. Two people with the same weight and height can have completely different health risks, depending on where that fat is stored, whether there are other associated conditions (such as high blood pressure, diabetes or sleep apnoea) and family history.

For this reason, Brazilian medical societies of obesity, diabetes, cardiology, endocrinology and sleep met and developed, in 2025, a joint guideline with a central proposal: before deciding how to treat someone's obesity, it is first necessary to understand that person's cardiovascular risk.

This is because obesity does not harm health just because of weight itself. It contributes to the development of heart problems in two ways:

  1. Indirectly, by increasing the chance of high blood pressure, type 2 diabetes and high cholesterol which in turn damage the heart and blood vessels over the years.
  2. Directly, because excess fat, mainly abdominal, generates a chronic inflammatory state in the body that affects the structure and functioning of the heart, even in people who have not yet developed diabetes or high blood pressure.

A striking piece of data: even people with BMI below 30 that is, technically "overweight" and not "obese" can have elevated cardiovascular risk if the fat is concentrated in the belly area. This is why so much importance is now given to waist measurement, and not just the scales.

How is this risk assessment done?

In practice, the doctor will look at a set of information, much like the case I demonstrated at the beginning:

  • Age
  • Blood pressure
  • Cholesterol and triglycerides
  • Whether the person already has diabetes, or is on the path to developing it
  • Whether they have already had a cardiac event (heart attack, stroke) or arterial problem
  • Kidney function
  • Presence of sleep apnoea
  • Family history of early cardiac disease

Based on this, the person is classified into three major groups:

  • Low risk: less than 5% chance of having a serious cardiovascular event in the next 10 years
  • Moderate risk: between 5% and 20%
  • High risk: above 20%, or presence of factors that automatically place the person in this group (such as long-standing diabetes, advanced kidney disease, very high cholesterol or history of heart attack/stroke)

There is also a separate category of high risk for heart failure, which includes, for example, people with severe obesity (BMI above 40), obesity associated with both diabetes and high blood pressure at the same time, severe sleep apnoea or symptoms such as tiredness and disproportionate breathlessness exactly the symptoms our fictional patient reported and which she herself did not value.

This classification is not medical bureaucracy: it is what will define, among other things, which treatment has the best chance of truly protecting that person's health and this is where the so-called "weight-loss pens" come in.

Why the goal is not just "losing weight", but losing the right weight

A very interesting point brought up by specialists is that the amount of weight lost matters, and it changes according to the goal:

  • A loss of 5% of body weight is already enough to improve blood pressure, cholesterol and significantly reduce the risk of developing type 2 diabetes.
  • To actually reduce the risk of serious cardiovascular events like heart attack and stroke, studies indicate that it is ideal to lose at least 10% of the maximum weight ever reached in life.
  • In people with atrial fibrillation (a heart rhythm disorder) associated with obesity, losing 10% of weight also significantly reduces symptoms and episodes.

In other words: it is not about aesthetics, it is about a measurable therapeutic goal, just as the dose of a blood pressure or diabetes medication is measured.

And where do the weight-loss pens fit into all this?

In recent years, a new generation of injectable medications for obesity has emerged popularly called "weight-loss pens" which represent a real change in the way obesity is treated. The most well-known are based on the substances semaglutide and tirzepatide.

These medications mimic natural hormones from the body itself (called GLP-1, and in the case of tirzepatide, also GIP), which act by controlling appetite, satiety and sugar metabolism. The result, in clinical studies with thousands of patients, was weight loss much greater than achieved by diet and exercise alone in some studies, between 15% and almost 20% of body weight.

But the most important piece of data, and what motivated much of the update to medical guidelines, is not just how much weight these people lost. It is what happened to their hearts:

  • A large international study followed more than 17,000 people with obesity and established cardiovascular disease. Those who used semaglutide had 20% fewer serious cardiac events (heart attack, stroke or cardiovascular death) than those who used placebo even with a relatively modest weight loss of about 9%.
  • In people with type 2 diabetes, different medications in this class consistently reduced heart attack, stroke, hospitalisations for heart failure and even kidney problems.
  • In patients with heart failure associated with obesity, both semaglutide and tirzepatide showed real improvement in quality of life, walking capacity and symptoms, with reduced hospitalisations.
  • In people with moderate to severe sleep apnoea associated with obesity, tirzepatide became the first medication approved specifically for this purpose, significantly reducing the severity of apnoea.

This is why, today, these medications are no longer seen merely as "weight-loss drugs". In people with moderate or high cardiovascular risk, they have come to be recommended as part of heart care, exactly in the same way as a cholesterol or blood pressure medication.

This does not mean they are indicated for everyone who wants to lose a few kilos, nor that they replace lifestyle changes. On the contrary: the guidelines are clear in stating that diet, physical activity and monitoring with a multidisciplinary team remain the basis of treatment, and that medication comes in as an additional tool specially indicated when there is cardiovascular risk involved, and not just the aesthetic desire to lose weight.

And what about bariatric surgery?

It is worth noting that, despite the advancement of weight-loss pens, bariatric surgery continues to play an important role mainly in people with more severe obesity (BMI equal to or above 35) who already have moderate or high cardiovascular risk, and who have not achieved satisfactory results with available clinical treatment. Long-term studies, with more than 14 years of follow-up, show significant reduction in cardiovascular mortality in these patients.

If we could sum all this up in a few sentences, it would be like this:

  1. Obesity should not be treated by looking only at the scales, but by the real risk it represents for each person's heart.
  2. This risk is calculated by considering blood pressure, cholesterol, diabetes, family history, kidney function and other factors — and not just BMI.
  3. The weight loss goal changes according to this risk: 5% already helps control factors like blood pressure and cholesterol; 10% is what is usually necessary to actually reduce the risk of heart attack and stroke.
  4. Weight-loss pens (semaglutide, tirzepatide) have stopped being seen merely as aesthetic medications and have come to be recommended, with strong scientific backing, especially for those who have obesity associated with moderate or high cardiovascular risk, diabetes, heart failure or sleep apnoea.
  5. None of this replaces individual assessment with a doctor. Cases show that "trivial" symptoms such as tiredness, breathlessness, a larger waist, can be signs of a risk worth investigating before, not after a serious event.

If you identify with this or have doubts about your own cardiovascular risk related to weight, the first step is always to talk to a doctor, who can assess your case individually and recommend the most appropriate treatment for you.

This content is for informational purposes and does not replace a consultation. For a better assessment, see a doctor.

Dr. Rebeca Soares Andrade CRM - GO 39335