What's the best vegan alternative to milk? The research institute also reports that one in seven children in Germany is overweight. Worldwide, 340 million children and adolescents were overweight or obese in 2016, according to the World Health Organization (WHO). In addition, there are 38 million overweight children under the age of five. Around the world, the number of overweight people has almost tripled since 1975, especially in industrialized nations. This means, for a large number of children in the world — a majority of whom are not vegan or vegetarian — a healthy diet is sorely lacking. Vegan = healthy? Not necessarily The fact is, no matter which diet someone subscribes to, if they don't pay attention to what their nutritional needs are, their health will suffer.