Ultra-high-caloric, Fatty Diet in ALS

Inclusion Criteria: * Possible, probable (clinically or laboratory supported) or definite amyotrophic lateral sclerosis according to the revised version of the El Escorial criteria * Disease duration (onset of first paresis or bulbar symptoms) \< 24 months * Loss of amyotrophic lateral sclerosis functional rating scale revised of ≥ 0.33 points/month based on the formula: (48 - myotrophic lateral sclerosis functional rating scale revised score at screening visit) / (months between onset and screening visit) * Age ≥18 years. * Either continuously treated with a stable dose of riluzole, OR not treated with riluzole for the last 4 weeks prior to inclusion * Either continuously treated with a stable dose of edaravone, OR not treated with edaravone for the last 4 weeks prior to inclusion * Either continuously treated with a stable dose of sodium-phenylbutyrate/taurursodiol, OR not treated with sodium-phenylbutyrate/taurursodiol for the last 4 weeks prior to inclusion * Capable of thoroughly understanding all information given * full written informed consent according to good clinical practice Exclusion Criteria: * Previous participation in another interventional study involving an active treatment within the preceding 4 weeks * Tracheostomy or continuous permanent ventilator dependence (\>22 hours per day) * Pregnancy or breastfeeding * Any medical condition known to have an association with motor neuron dysfunction which might confound or obscure the diagnosis of ALS * Presence of any concomitant life-threatening disease or impairment likely to interfere with functional assessment. * Evidence of a major psychiatric disorder or clinically evident dementia precluding evaluation of symptoms. * Liable to be not cooperative or comply with study requirements as assessed by the investigator, or unable to be reached in the case of emergency