What does a negative energy balance mean?

Unintentional weight loss results from a negative energy balance. In this case, food intake (due to swallowing difficulties, loss of appetite, and other factors) is lower than the actual energy requirement. The energy balance can be further worsened if there are particularly high energy requirements (e.g., due to increased respiratory effort) or an elevated resting metabolic rate (increased metabolism in ALS).

The goal of nutritional therapy is to prevent a negative energy balance and to ensure an adequate intake of calories and nutrients. An adult’s energy requirement is 30 kcal per unit of normal body weight. Normal body weight, in turn, is calculated using a simple formula: Height in cm minus 100. For example, the normal weight of a person who is 170 cm tall is 70 kg (calculation: 170 cm height minus 100 = 70 kg). In this case, the daily energy requirement is as follows: 30 kcal × 70 kg = 2,100 kcal.

A similar calculation can be made for each patient. Calculating energy requirements is the responsibility of dietitians, who should be involved in the patient’s care. They have the necessary experience and calculation methods to determine the caloric content of the food actually consumed and the unmet energy requirements.