Weight loss is a known negative prognostic factor in amyotrophic lateral sclerosis (ALS). Over the last years, various interventional studies targeting the energy deficit in ALS yielded promising results; however,it is still unclear which kind of nutrition or nutritional supplement is most beneficial. Moreover, there is lack of evidence regarding interventions in patients with a PEG in later disease stages.In a pilot study conducted in 2013, it was demonstrated that body weight can be stabilized in ALS by applying either a fat-rich or carbohydrate-rich high-caloric food supplement. In 2014, Wills et al. conducted a placebo-controlled randomized controlled pilot study, which indicated that a carbohydrate-rich, hypercaloric diet, consisting in 125% of estimated energy requirements as determined by indirect calorimetry, in patients fed via percutaneous endoscopic gastrostomy was safe and well tolerated. Moreover, these patients showed longer survival than patients fed with a fat-rich, hypercaloric diet or an isocaloric diet . Hypercaloric, high-carbohydrate diet also showed beneficial effects on body weight and Body Mass Index . Although these results were promising, the low number of patients (n=24) was a severe limiting factor of this study. The aim of this study is to investigate the effect of a hypercaloric PEG nutrition, consisting of 120% of estimated calorie requierements, compared to an isocaloric nutrition. Individual energy requirement is determined by performing indirect calorimetry and activity questionnaire. The investigators hypothsize, that a hypercaloric PEG nutrition slows down disease progression as measured by neurofilament light chains (NfL) in serum after 6 months compared to placebo. Power calculation relies on the results of the lipids and calories for ALS (LIPCAL-ALS) study which tested the effect of an oral high-caloric fatty nutritional supplement in ALS. The study revealed that NfL serum values declined significantly in the intervention group while remaining stable in the placebo group over the course of the study. Assuming a similar effect size, we calculated that 76 patients had to be included in the current trial.