From key stage 1 onwards pupils are encouraged to "express their own views about people, places and the environment" (PoS 1c), and vegetarianism offers a topical, relevant stimulus.
With younger children this is best developed through locality-study and the key geographical question: "What is this place like?" (KS12 PoS 3a) For example, food - its look, smell and taste - is a great way to foster a sense of place. Many schools follow Unit 10 about Chembakolli, in India, and a vegetarian food experience as part of this unit would add value to the geography.
Many teenagers have strong views about vegetarianism and there are good vehicles for exploring the issues in the KS3 PoS and in the GCSE specifications. For example:
PoS 6 f iii - "the interrelationship between population and resources" offers the chance to consider the Earth's potential to feed itself and the impact on this equation of "energy loss" from feeding crops to animals
PoS 6 j i - "how conflicting demands on an environment arise" offers the chance to investigate the impact of, for example, extensive cattle ranching on land availability in less economically developed countries
PoS 5 b - "explore the idea of sustainable development" could include looking at the impact of different farming systems.
Vegetarianism provokes lively debate in class as there are likely to be "conviction vegetarians" present whose choice of lifestyle isn't based on decisions their parents have made. Some children choose vegetarianism for dietary reasons, others for moral ones. It relates to home economics, PSHE and RE.
For GCSE religious studies ethics options, it links with Genesis 1.28 and the debate about whether humankind's custody of animals means looking after them or divine permission to eat them. Whatever the curriculum slot or the age of the child, teachers will want two key skills to emerge from the debate: understanding of the issues involved, and tolerance for the "other" side. The latter may be difficult in a society that can confuse apathy with tolerance.
Use story texts (Farmer Duck or Animal Farm) and video (Chicken Run) to then write arguments for and against eating meat. Invent appropriate and inappropriate names, such as Reverend Cowherd - vegetarian, Tony Deaf - musician, Mr Illman - doctor. Look up some word derivations: pigpork, cowbeef, sheepmutton.
Conduct a survey of food likes and dislikes. Present the information as graphs.
Cooking vegetarian dishes. What are vitamins and what do they do? What happens to vitamins in processed food? Investigate teeth - the care of them and the type and growth of human and animal teeth.