A case to start the conversation

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

  • BMI of 34 kg/m² (class 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 fatigue and a sensation of shortness of breath when climbing stairs, which she always attributed to "age" or "sedentary lifestyle"

Marisa is a very common example. She does not have diagnosed diabetes, has not had any cardiac event to date, and for that reason 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 that completely changes the way obesity treatment should be conducted with her.

It is precisely this type of situation that is becoming increasingly common in medical offices, which motivated an important update in how Brazilian physicians are being guided to treat obesity: not only "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 for purely illustrative purposes, serving to facilitate understanding of the topic addressed."

Obesity is not just about the scale

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

For this reason, Brazilian medical societies specializing in obesity, diabetes, cardiology, endocrinology, and sleep came together and developed, in 2025, a joint guideline with a central proposal: before deciding how to treat someone's obesity, one must first understand that person's cardiovascular risk.

This is because obesity does not harm health merely because of the 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, particularly abdominal fat, creates 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 fact: even people with a BMI below 30 — that is, technically "overweight" and not "obese" — can have elevated cardiovascular risk if fat is concentrated in the belly area. This is why so much importance is now given to waist measurement, and not just the scale.

How is this risk assessment performed?

In practice, the physician will look at a set of information, very similar to 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 problems
  • Kidney function
  • Presence of sleep apnea
  • 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 apnea, or symptoms such as fatigue and shortness of breath out of proportion — exactly the symptoms the fictitious patient reported and that 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 actually protecting that person's health — and this is where the so-called "weight loss pens" come in.

Why the goal is not just "lose weight," but lose 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 objective:

  • A loss of 5% of body weight is already sufficient 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 the ideal is to lose at least 10% of the maximum weight ever reached throughout life.
  • In people with atrial fibrillation (a cardiac arrhythmia) associated with obesity, losing 10% of body weight also significantly reduces symptoms and episodes.

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

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" — that represent a real change in how obesity is treated. The most well-known are based on the substances semaglutide and tirzepatide.

These medications mimic natural hormones of 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 far superior to that achieved with diet and exercise alone — in some studies, between 15% and almost 20% of body weight.

But the most important finding, and what prompted 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, hospitalizations 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 hospitalizations.
  • In people with moderate to severe sleep apnea associated with obesity, tirzepatide became the first medication approved specifically for this purpose, significantly reducing the severity of apnea.

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 become recommended as part of heart care, exactly 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 pounds, 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 continue to be the foundation of treatment, and that medication comes in as an additional tool — particularly indicated when cardiovascular risk is involved, and not merely the aesthetic desire to lose weight.

And what about bariatric surgery?

It is worth noting that, even with the advancement of weight loss pens, bariatric surgery continues to play an important role — particularly 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 summarize all of this in a few sentences, it would be like this:

  1. Obesity should not be treated only by looking at the scale, 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 — not just BMI.
  3. The weight loss goal changes according to this risk: 5% already helps control factors such as 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 ceased to be seen merely as aesthetic medications and have become recommended, with strong scientific support, especially for those with obesity associated with moderate or high cardiovascular risk, diabetes, heart failure, or sleep apnea.
  5. None of this replaces individual evaluation with a physician. Cases show that "trivial" symptoms like fatigue, shortness of breath, or an increased waist size can be signs of a risk worth investigating beforehand, not after a serious event.

If you identified with this or have questions about your own cardiovascular risk related to weight — the first step is always to talk with a physician, who can evaluate your case individually and indicate the most appropriate treatment for you.

This content is informational in nature and does not replace a consultation. For a better evaluation, please see a physician.

Dr. Rebeca Soares Andrade CRM - GO 39335