However, if weight loss is not linked to these factors or diet or increased physical activity, a doctor should be seen to assess the cause of the problem, which could be thyroid disease, diabetes, tuberculosis, or cancer.

Possible causes


In general, when unintentional weight loss occurs for no apparent reason, it may be due to gastrointestinal disorders, neurological diseases, thyroid problems such as hyperthyroidism, chronic obstructive pulmonary disease, and infectious diseases such as tuberculosis and AIDS, for example. Also, it may be due to diabetes, psychological problems such as depression, excessive use of alcohol or drugs, and cancer.

Weight loss can also have specific causes according to the person’s age and associated situations, such as:

1. In the elderly


Weight loss during aging is considered normal when it is slow, and it is usually linked to lack of appetite, change in taste, or side effects of medications. Another common reason is dementia, which makes people forget to eat and eat properly. In addition to weight loss, it is also normal to have a loss of muscle mass and bone mass, which makes the elderly more fragile and at greater risk of having bone fractures.

2. In pregnancy


Weight loss during pregnancy is not a normal situation, but it can occur mainly when the pregnant woman has a lot of nausea and vomiting in early pregnancy and is not able to eat properly. In these cases, it is essential to consult a nutritionist to know what to do and to avoid serious complications that could impair the growth of the fetus, as it is expected that a healthy pregnant woman with normal weight will increase by 10 to 15 kg during the entire pregnancy.

3. In the baby


Weight loss is common in newborn babies, who tend to lose up to 10% of their body weight during the first 15 days of life, due to the expulsion of fluids through urine and feces. From then on, it is expected that the baby will increase about 250 g per week until 6 months of life and will always increase in weight and height as age advances. If this does not happen, the baby must be constantly monitored by the pediatrician so that there are no changes in his development process.

How is the diagnosis


It is important to know the cause of weight loss so that the doctor can indicate the most appropriate treatment and, thus, it is possible to prevent complications. Therefore, to diagnose the cause of weight loss, the doctor must assess the symptoms and order tests as suspected, such as blood, urine, and stool tests, MRI or chest X-ray, continuing the investigation according to the results obtained.

Generally, the general practitioner or family doctor is the first doctor who should be consulted, and only after the results of the exams can they indicate a specialist according to the cause of the problem, such as an endocrinologist, psychiatrist, or oncologist, for example.

To help assess the cause of the problem, look for signs and symptoms that could indicate cancer.

when to worry


Weight loss is worrisome when the patient unintentionally loses more than 5% of body weight in a period of 1 to 3 months. In a person weighing 70 kg, for example, the loss is worrying when it is greater than 3.5 kg, and in a person weighing 50 kg, the concern comes when she accidentally loses another 2.5 kg.

In addition, you should also be aware of signs such as tiredness, loss of appetite, changes in the rhythm of bowel movement, and an increase in the frequency of infections such as the flu.