“You have to lose weight.” Many of the people who read these lines have probably heard these words from their doctor on occasion. The words overweight and obesity are not exactly unknown in our society, with excess weight being an increasingly serious and relevant problem that can have severe repercussions in our lives.

But… what is the difference between overweight and obesity? Let’s see it throughout this article.

A question of health and nutrition

Overweight is understood as a situation in which a subject weighs more than what is considered normative and healthy, taking into account his or her height, age and sex. As far as obesity is concerned, it implies a situation (classifiable as a disorder according to some authors) in which the subject in question maintains an excessive and generalised accumulation of body fat throughout the body.

In both cases, we are dealing with excess weight and body mass. And although many people who diet or exercise do so mainly to conform to a specific beauty canon , the truth is that this problem goes much further: excess weight is a risk factor that facilitates the appearance of different diseases and can even lead to death from heart or respiratory problems.

Such excess is often derived from a sedentary life and excessive intake , although there are diseases, alterations or conditions in which obesity appears without the two previous factors being present (for example, hyperplastic obesity, which is produced because the person has an excess of adipose cells (the one produced by excessive intake is due to the fact that these cells are larger, not because there are more).

Main differences between overweight and obesity

Both overweight and obesity refer to an excess of body fat , being closely related concepts whose main differences are of degree (the person with obesity has a higher proportion of fat than the one who is overweight). Moreover, at first sight it is difficult to distinguish the limits between one and the other. But even though they are so similar, the truth is that there are a series of differences to be taken into account when it comes to recognizing them.

1. Body Mass Index (BMI)

The Body Mass Index or BMI is a parameter used to assess the level of body fat. It is calculated by looking at the ratio of weight to height squared. In this index we find one of the technical differences between overweight and obesity.

It is considered that a BMI value of less than 18.5 implies an underweight or weight below the recommended and healthy, and can be seriously harmful to health. Between 18.5 and 25 would be the BMI considered as normopesos, with a healthy proportion between weight and height. From values greater than 25 we would already be able to observe body masses above the healthy range .

Between 25 and 26.9 we would be between overweight in grade 1, from 27 to 29, 9 in overweight grade 2 (also called pre-obesity), between BMI 30 and 34.9 we would be in obesity type 1 and obesity type 2 would be between 35 and 39.9. Finally, we would find that body masses with a BMI of 40 to 49.9 would be considered morbid obesity (or type 3), and one of more than 50 would be called extreme or type 4 obesity.

In conclusion, one of the differences between obesity and overweight is that, as far as BMI is concerned, between 25 and 30 would be considered overweight and from a BMI of 30 we would be talking about a case of obesity.

2. Risk level

Another of the main differences between overweight and obesity, and actually the most important one, is found in the risk that the maintenance of these body fat levels implies for the health of the person who suffers them.

Obesity has been shown to be a major risk factor for the emergence of different pathologies.

The most common and well known are heart disease and arteriosclerosis (with the consequent increased risk of vascular and cerebrovascular events such as stroke). Also high blood pressure, bone problems, type 2 diabetes, respiratory problems such as bronchitis , liver and kidney problems, sleep apneas or low back pain, sexual dysfunctions and even fetal malformations in the case of pregnant women. Also, surgical procedures and the effects of anesthetics are more dangerous, there are more sleep problems and a greater tendency to anxiety and depression.

The risk of death from one of the above problems (especially cardiovascular and respiratory problems) is greatly increased compared to the population with normal weight.

As far as the level of risk is concerned, in the case of those people who would be in the so-called pre-obesity (with BMIs of around 27-29.9) they would have a slight risk of suffering the above problems. However, within obesity we can find that those with a BMI between 30 and 35 have a moderate risk, if they have between 35 and 40 a high risk and if they have more than 40 a very high risk.

3. Interventions carried out

Another difference between the two can be found in the treatment carried out to solve it. In overweight, the main indications are the prescription of physical exercise and adequate nutritional guidelines. This would also be advisable for people with obesity, although depending on the case and the risk of appearance or worsening of other problems in this case may require surgery .

4. Causes

The causes of both problems are multifactorial, with the interaction of various elements leading to overweight or obesity. Generally, one of the best known is the dysregulation of the nutritional balance , by consuming many more calories than we burn. In other words, eating too much and/or badly and doing little exercise to counteract it. But this is not the only relevant factor. There are also genetic causes, metabolic diseases or the consumption of drugs and substances.

The reason why we have added this aspect as a difference is because those people who have certain genetic type problems and/or developmental and metabolic diseases tend to evolve (if not controlled) towards obesity. On the other hand, the overweight that does not go away is usually more typical of situational factors (although there is also a certain hereditary tendency).

5. Consideration of illness

Although both concepts are worrying, the truth is that obesity is already considered a disease or disorder , while overweight is a risk factor but is not identified as a disorder itself but as a condition.