Assessment of resting energy expenditure (REE) by indirect calorimetry (IC) in 1400 healthy individuals for arithmetical transformation into an bedside tool to estimate energy requirements in dietary practice (BASAROTs). A multinational, multicenter, prospective cross-sectional study.

The assessment of energy expenditure is the basic requirement for any nutritional therapy. Nevertheless, there is still no accurate, scientifically validated and practical bedside tool.

The reference method for energy expenditure measurement is indirect calorimetry (IC). High costs, time requirements and the need for trained personal are main reasons for its limited use in clinical practice. Also arithmetical calculations, such as the Harris-Benedict equation, are not widely accepted.

In general energy expenditure is often estimated by so called rules of thumbs, a method requiring only one multiplication with body weight (for example: 25 kcal/kg body weight). Sex, age and BMI are usually not considered, although they are independent predictors of energy expenditure. Thus, energy expenditure estimations are often inaccurate, especially in older and overweight/obese persons.

Therefore, it is important to develop a bedside tool that is more accurate but simple enough to be accepted by practitioners. In 2004, the Austrian Society of Clinical Nutrition published the first BMI, aged and sex adapted rule of thumbs, called BASAROTs (BMI Age Sex Adjusted Rule Of Thumbs). Those were, however, based on results of the Harris Benedict equation.

The main objective of the present study is, therefore, to replace the existing BASAROTs by BASAROTs based on actual measurements of resting energy expenditure by indirect calorimetry (IC-BASAROTs).

Inclusion Criteria:

• female, male
• 18 years to 85 years
• Body Mass Index: 14,0 - 49,9 kg/m²
• Eastern Cooperative Oncology Group (ECOG) Performance Status (Grade 0 or 1)
• normal thyroid function
• subjective health in dependence of BMI (underweight, normal weight, obesity, morbid obesity)

Exclusion Criteria:

• implanted pacemaker
• amputations
• paresis (mono- and diparesis)
• Asian or African descent
• above-average physical activity (competitive sport)
• present or suspicion of malignant neoplasms (tumors, metastases, hemato-oncological diseases)
• severe diseases (organ diseases, neurological diseases)
• severe dementia (MMSE < 20 points)
• pregnancy
• participation in other trials
• subjects with expect non-compliance to protocol guidelines
• intake of:
• lithium compound
• neuroleptics: Olanzapine (Zyprexa ®), Clozapine, Sertindole, Ziprasidone, Haloperidol, Thioridazine
• anticonvulsant (Carbamazepin, Valproic Acid, Topiramate)
• noradrenalin-reuptake-inhibitor (NARI): Reboxetine , Atomoxetine
• tricyclic antidepressants (Amitryptiline, Clomipramine, Doxepin, Imipramine, Trimipramin)
• Lorcaserin
• interferon-alfa, interferon-beta
• Baclofen
• Orciprenaline
• Amiodarona
• Insulin
• corticoid therapy (oral)

Minimum sample size of n = 1400: 700 mostly healthy people (50% women, aged 18-100 years, BMI 16.5 to 39.9 kg / m²), 420 underweight individuals (50% women, 18 years to 100 years, BMI from 14.0 to 16.4 kg/m²), 280 morbidly obese (50% women,18 years to 100 years, BMI 40.0-49,9 kg/m²).

Recruitment of volunteers is performed in the local trial centers.

The other study centers forward us pseudonymised participant data for evaluation. It might also be possible that we share selected pseudonymised participant data with the other study centers.