The vegan and plant-based diet trend has risen with widening concerns about animal agriculture, factory farming, climate change and the environment.

But going meat-free is easier said than done. For one thing, meat tastes good.

Some experts like University of Newcastle Professor of Nutrition and Dietetics Clare Collins believe becoming "flexitarian" is more practical. That is, focusing on vegetarian meals while sometimes consuming food like red meat, poultry and seafood.

For those who decide they want to give this a go, or a vegan or vegetarian diet, they'll need different sources of protein.

Which brings us to something called seitan, which has become a new food trend. It's relatively high in protein and iron.

Dr Kerith Duncanson, a dietitian and University of Newcastle researcher, said seitan can be made by washing the starch off flour, leaving mainly gluten.

"Wheat gluten has been used as a substitute for meat in Asian countries for centuries, particularly among Buddhists who prefer not to eat meat," she said.

Seitan is that spongy, soggy thing served at Chinese restaurants.

Kerith said she first had seitan at a Chinese restaurant when she was a university student.

"I investigated what it was made from because I was a curious dietetics student."

It's kind of funny that seitan is now seen as a "good guy" because gluten has been seen as a "bad guy" for years among the wellness brigade, due to some people experiencing problems when they eat wheat.

"It is definitely the bad guy for those with coeliac disease. And I think gluten was blamed for some of the symptoms that FODMAPs (fermentable carbs in foods, including wheat) cause in those with IBS," Kerith said.

"Gluten-free was also popularised by influencers in the early days of social media, so it got traction. And the food industry understandably gets on board with consumer demand. It seems to have spread from there, but burnt itself out eventually."

Kerith said a meat-free diet can be OK, "if done in a balanced way".

"But often foods get cut out without being replaced by nutritionally equivalent ones. This can lead to low blood levels of vitamin B12, iron and zinc," she said.

"Because some vitamins and minerals can be stored in our body, it can take months or years for our stores to be depleted, so we don't realise we aren't eating enough."

The meat-free trend has led companies to produce so-called drug-free and cruelty-free "lab meat".

Companies are developing lab-grown chicken, beef and pork over concerns about animal welfare, the climate and environment.

Asked whether she thought meat grown in a lab would become the norm, she said: "I believe it will be a part of our future meat consumption patterns, as traditionally farmed meats become less affordable".

Ross Iles, of Vacy, says a large cave near Wallsend was known to him and his mates as "Cavey".

"How does someone think of a name like that?" he quipped, adding that he was born and bred in Wallsend.

"We used to go there and play, take sausages and cook them with a piece of wire through them."

In Friday's Topics, Wallsend's Alf McDonald told us about a cave of his boyhood, not far from Wallsend.