Unhealthy eating patterns and dissatisfaction with weight and shape are common in the population, especially at certain stages of life such as adolescence.
Studies vary. A recent review of 94 studies estimated that the lifetime prevalence (the percentage of the population over their lifetime) with eating disorders is 2.2% of males and 8.4% of females. That is about 1 in 50 men and 4 in 50 women.
Source: Galmiche et al (2019) American Journal of Clinical Nutrition. 109 (5): 1402-1413.