<p>Weight loss is frequently observed in early–stage amyotrophic lateral sclerosis (ALS) and is considered an independent predictor of survival. Weight loss observed in ALS is associated with multifactorial etiology, including muscle wasting and dysphagia. Recent studies have implicated disease–specific hypermetabolism as one of causes of weight loss in ALS. Involvement of the hypothalamus in ALS has been the other topic in metabolic dysfunction in ALS. TDP–43 protein aggregates detected in the hypothalamic subnuclei may be associated with weight loss or abnormalities of eating behavior in patients with ALS. Nutritional intervention to maintain body weight could become one of disease–modifying therapies, and recent studies have reported that slowing of weight reduction rate after diagnosis was associated with better survival and that a high–calorie fat diet improved survival in patients with rapidly progressive disease. Nutritional education regarding a high–calorie diet, weight control, and early gastric tube placement is required at the time of diagnosis. Formulas to estimate the recommended daily energy intake for patients with early–stage ALS were reported from USA, Europe and Japan. Multidisciplinary team approach and rehabilitation is necessary to support patients with swallowing disturbance. Surgical intervention to prevent aspiration is often needed for patients who frequently develop aspiration pneumonia.</p>