The term “weight loss” refers first of all to an intentional or unintentional reduction in body weight. Losing weight during a diet is a desirable effect. Inadvertent severe and sudden weight loss, on the other hand, is a warning signal and can indicate illness or parasites.

Most people in Western countries are particularly concerned with their own body weight when they are overweight and want to reduce excess pounds on the stomach and thighs. Numerous diets, exercise and lifestyle recommendations deal with the question of how excess body fat can be successfully and permanently reduced.

Unintentional weight loss, on the other hand, can also be the result of an underlying disease. This is particularly true when the reduction in body weight occurs quickly and without noticeable cause, such as a change in diet or increased physical activity. In the case of inexplicable weight loss, a doctor should always be consulted to clarify the causes. It may also be helpful to question one’s own diet in everyday life.

Causes of unwanted weight loss

In most cases, weight loss is a desired effect based on changes in diet and lifestyle, such as a diet or increased physical activity. Unintentional reductions in body weight, on the other hand, are a possible sign of physical or mental illness and should be examined by a doctor.

The weight loss may be due to the following:

  • Poor nutrition
  • starvation
  • unbalanced or inappropriate nutrition leading to deficiencies (e.g. inappropriate diets)
  • Gastrointestinal diseases and digestive disorders
  • Infectious diseases caused by bacteria or viruses, especially if they are chronic
  • Parasite infestation of the intestine (e.g. by a tapeworm)
  • Food allergy (e.g. to chicken protein or nuts) or food intolerances (e.g. lactose or gluten intolerance)
  • chronic inflammatory bowel diseases (ulcerative colitis, Crohn’s disease)
  • liver or pancreatic diseases
  • Problems in the mouth/tooth area
  • toothache, periodontitis (periodontosis) or badly fitting teeth
  • chronic inflammation of the mouth or throat
  • cancers
  • cancer in the gastrointestinal tract (oral cavity, larynx, oesophagus, stomach, small intestine, colon) that affects food intake, transport or utilization
  • liver, bile duct or pancreatic cancer
  • advanced stages of any other type of cancer
  • hormonal disorders
  • Diabetes mellitus (diabetes)
  • hyperthyroidism
  • pancreatitis
  • Mental and psychosomatic diseases, nerve diseases
  • depressions
  • eating disorders such as anorexia, eating-break addiction
  • dementia
  • alcoholism (alcoholism), drug or drug addiction

Strong weight loss: When to go to the doctor

A significant weight loss without apparent reason should always be examined by a physician. The possible physical causes of the weight loss must be recorded as well as psychological illnesses or unsuitable eating habits.

To diagnose weight loss, the doctor first conducts a patient interview in which the patient’s medical history and especially the exact change in body weight is recorded. In particular, previous illnesses or events that could be connected with the current weight loss are important. This can

  • changed lifestyles,
  • previous abdominal surgeries,
  • liver or kidney disease,
  • Metabolic disorders,
  • mental illness,
  • the taking of medication or also
  • travel to exotic countries (parasite infestation).

In addition, a weight protocol is often drawn up in which the development of the body weight is continuously recorded. The physical examination then records the exact extent of the weight loss, its possible physical causes and other existing illnesses.

Often the conversation and examination already leads to an initial suspicion of the cause of the weight loss.

Blood tests on the general state of health, sugar and fat metabolism as well as on hormone levels, liver and kidney function provide further information on possible causes of weight loss.

On this basis, further targeted imaging examinations or examinations aimed at the function of individual organs are then carried out. For example, a glucose load test can be used to determine whether diabetes is present. Ultrasound, organ endoscopies (e.g. of the stomach or intestine) and three-dimensional X-ray or magnetic field images help in the search for inflammatory processes and, if necessary, cancerous tumours.

Last but not least, psychological aspects can also play a role. Conversations or even special tests can give indications of depression and psychosomatic illnesses.

Cause for weight loss should be treated

The therapy of an unintentional weight loss is directed as far as possible against its cause. Nutritional errors should be corrected, deficiencies corrected and underlying illnesses treated so that there is no permanent consequential damage.

If the diet is inadequate or one-sided, the food supply must be adapted and adapted to the physical strain. The doctor, nutritionist and supplementary literature on a healthy and balanced diet provide advice and information.

If underlying diseases such as metabolic or hormonal disorders are present, they must be treated with appropriate therapy in order to get the trigger for weight loss under control. In some cases, special diets (e.g. with a high calorie content) or special foods (e.g. so-called astronaut food) make sense. If a normal diet is no longer possible, a stomach tube or infusions can ensure a sufficient diet.

A particular challenge is often the diet for advanced cancers. In these cases, the actual problem is often not the supply and absorption of food, but cancer-induced metabolic shifts, which can lead to an extreme increase in the body’s nutritional requirements.

Psychological and psychosomatic nutritional disorders are treated with medication and psychotherapy.

Calorie calculator: How many calories do you consume per day?

Calculate calorie consumption: How it works

Although we consume calories every day, we also consume a certain part of them again. With our calorie calculator you can find out how high your basal metabolic rate is, how many calories you need and consume per day. But you can also calculate these values yourself, without a calorie calculator. You can find out what you need to do here.

The amount of energy our body consumes every day is called the calorie requirement or consumption. It is calculated from two essential factors:

Basal metabolic rate

If you do not want to use our calorie calculator, you can also determine your personal calorie consumption manually: In a first step, calculate the basal metabolic rate. Then calculate the value for your individual power consumption. At the end you multiply the two components and thus obtain your personal calorie requirement.

Without calorie calculator: How to determine your basal metabolic rate
Basal metabolic rate is the amount of energy your body would need in 24 hours of total rest lying down to maintain its basic functions. Basic functions include:

  • Breathing
  • digestion
  • brain activity
  • Maintaining body temperature
  • heartbeat
  • Activity of the organs
  • metabolic activities
  • Reconstruction of body substances such as cells, hair and nails

Calorie consumption in women vs. men

The basal metabolic rate is not the same for everyone. Factors such as age, weight, height, sex, muscle mass, state of health and climate influence the calorie requirement. For example, calorie consumption increases with mental activity, emotional reactions or hyperthyroidism. In contrast, the energy requirement is lower during sleep, under anaesthesia or when the thyroid gland is underactive. There are also differences between the sexes: the calorie requirement of women is on average ten percent lower than that of men. This is because men have more muscle tissue and less fat tissue than women.