There is no single pattern for the evolution of the nutritional status of children with autism spectrum disorder (ASD). Previous studies have found a tendency towards food selectivity with food monotony and difficulties with food texture in children with ASD, but studies in this area, especially in Brazil, are still scarce. The nutritional profile and changes in eating behavior were analyzed in patients with autism spectrum disorder assisted at a reference center in Belém. Eating behavior was assessed using the Labyrinth Scale, nutritional status assessment through weight and height (to calculate body mass index—BMI), and consumption food through the 24 h reminder. A total of 80 children of both sexes participated in the study, the majority of whom were male (80%), 47.5% eutrophic, while for the food consumption of the children evaluated, there was an average energy consumption of 1911 kcal daily, with 57.3%, 15.4%, and 27.3% of carbohydrates, proteins, and lipids, respectively. In relation to eating behavior, the highest averages were demonstrated in the domains of food selectivity, behavioral aspects, and mealtime skills. Masticatory motor scores showed a positive correlation with weight, BMI, and the amount of energy consumed by the child. The gastrointestinal symptoms score showed a negative correlation with the child’s age. Regarding mealtime skills, a negative correlation was observed with the proportion of carbohydrates in the diet and a positive correlation with the proportion of lipids consumed in the children’s diet. Therefore, knowing the main changes in eating behavior is important to ensure a complete and safe approach for each patient.