Mandy Kritz has not eaten meat or fish in eight years.
"When I was 14 it became clear to me that the cow grazing in a meadow is the same animal that ends up as meat on my plate," says the 22-year-old from the southern German town of Tuebingen about what motivates her.
She stopped eating meat but that brought new problems. "My mother thought it was a bad idea for me to become a vegetarian," Kritz recalls.
But she kept to her decision and began cooking for herself, she added.
"I showed my family that vegetarian cooking has more to offer than just potatoes with vegetables," Kritz says.
Dietician and author Dagmar von Cramm agrees. Von Cramm says there is nothing to be said against following a vegetarian diet, not even for schoolchildren.
"The only thing that might be in short supply is iron which is found in large quantities in meat," says von Cramm.
Young girls should take ensure that their iron levels do not sink when menstruating as the loss of blood leads to a loss of iron in the body.
Alternative sources of dietary iron are nuts and whole food products.
As long as a good source of iron has been found there is nothing wrong with a child becoming vegetarian, according to the Research Institute for Child Nutrition in Dortmund.
"But you do need greater awareness of food products than most people have," says Mathilde Kersting, the institute's deputy head.
Kersting says you just need to know which food products supply which nutrients. But Kersting and von Cramm are critical when it comes to a vegan diet.
Vegans do not eat meat and fish and exclude all animal products from their diet such as milk, eggs and honey.
"It's possible to follow this form of diet but it requires a very high degree of knowledge of nutrition," says von Cramm.
Kersting says she doubts whether young adults are able to follow a balanced vegan diet, but advises seeking professional advice if they should choose to do so.
Norbert Moch, nutrition expert at Germany's Vegetarian Association, agrees.
Moch says vegans must pay special attention to their intake of the B12 vitamin, which is normally found in animal products. Vegans no longer have B12 in their body after following the diet for a time.
Moch has been a vegan for 12 years and advises anyone thinking of becoming vegans to inform themselves thoroughly beforehand.