'Der Naschfuchs' is one of a series of picture-books by Erika Klein. All books of the series rank around a fox family; a mother with three fox kids. 'Naschfuchs' deals with the problem of children's overweight and the consume of too much unhealthy food. So, two of the fox kids are normal weight, active and sporty. The third child is overweight, bulky and immobile. The fox mother constantly worries about her third child, because it refuses to play like its siblings, it also doesn't eat anything at family's meals (afterwards, in secret, it empties the store cupboard). The mother fears a serious illness of her child.

The turning point comes when the mother admires her two healthy kids playing in the forest. The third one also tries to play in the same way, but fails. After that it denies unhealthy food. The story comes to its happy end, with the mother finally having three slender, sporty kids.