The last decade has seen a surge in popularity of veganism. There are different definitions of veganism. Strict vegans avoid anything where an animal has been involved (for example, the wearing of wool), and others are vegan only on a dietary level. The number of vegans in the UK has soared by 260% in the past ten years, so now 1.05% of the over-15 population (63% female, 37% male) consider themselves to be vegan, including 2% of all 15-34 year olds.*
So why the exponential increase?
In part, it is because veganism has become trendy. From being a niche way of living, it has now become acceptably mainstream, promulgated in particular by several internet bloggers turned cookery book authors, and is tied in with the "clean eating" message. But for most vegans, there are serious environmental, ethical and health concerns which underlie their choice.
Fears about sustainability and the environmental costs of raising animals as food has become a hot topic, as more people have become aware of the impact of rearing livestock. Proponents of veganism argue that globally, the meat and dairy industry is responsible for as much greenhouse gas emission as the entire transport sector. That figure is rising as the world population rises, and the people in developing countries are now eating vastly more meat than they used to.
There has been significant loss of biodiversity around the world due to the deforestation necessary to clear land for livestock production, which is being done on an increasingly industrial scale. This also has implications on a local level, with agricultural run-off polluting water supplies. Vegans also argue that their diet needs only one third of the land of a conventional diet, and they have only 50% of the carbon footprint. The environmental cost of raising food for livestock is a big concern, as 35 billion people could live off the food currently raised for animals; for every 100 calories fed to livestock, we only get 12 calories of meat in return, which is a poor use of world resources.
Greater awareness of the conditions in which farm animals live, and how they are slaughtered, has also inspired many people to become vegan. Most people interested in where their food comes from have seen photos or videos of chickens crammed together in huge sheds, or miles and miles of cattle stood in their own dung and being fed an unnatural diet of corn and soya pellets on "Concentrated Animal Feeding Operations" in the USA – both images that anyone who cares about animals finds uncomfortable at best. Although there are laws in Europe over how animals should be killed to cause them minimal distress, there are many examples where these rules are either accidentally or wilfully flouted, meaning some animals experience considerable distress before they are slaughtered, or worse, are only stunned and not dead when they begin to be "processed". Furthermore, laws to protect the welfare of animals in some countries are even less stringent than they are here.
Some follow a vegan diet due to concerns about their health. Stories of red and processed meat raising cancer risk have been prominent in headlines in recent years, and a plant-based diet has been linked to a lower risk of many major diseases.
So surely a vegan diet is a must for anyone concerned about the environment, animal welfare and their health?
There are some difficulties with following a totally vegan diet. Whether we like it or not, we are omnivores and it is 
impossible to fulfil our nutritional needs on a purely plant-based diet. Although vegans often do have a healthier diet than the average omnivore, eating more fruit and vegetables, a vegan diet isn't intrinsically healthier (after all, a diet of soy burgers and chips is vegan!). Contrary to popular belief, vegans are rarely deficient in protein as most people eat far more than they need, but vegans do have to plan carefully to ensure adequate intake of vitamin D, omega 3 fatty acids, iodine, calcium, iron, zinc and selenium, which ARE all available from plant sources, but in much smaller quantities than in animal foods. Vitamin B12 is not available from plant sources at all (although some types of marine algae are believed to contain vitamin B12, this is in a form that cannot be used by the human body). The only way for a vegan to get adequate vitamin B12 is from fortified foods or supplements. Vegans feel this is a small price to pay for the benefits that veganism brings, but a fully vegan diet isn't the way forward for everyone.
Perhaps the solution is to think far more carefully about how we consume animal products. Rather than just eating the muscle meat, nose-to-tail eating means making use of (highly nutritious) offal, and using bones for stock, so more meals are provided per animal slaughtered. Rather than eschewing ALL animal products, perhaps we could all eat much less of them. We don't need animal products at every meal, but a small amount of high-quality offal, muscle meat, eggs or dairy food once a day would ensure that nutritional needs are met and would mitigate the health issues concerning processed meat. We could all eat lower and more sustainably on the food chain – rather than choosing beef, opt for chicken. Instead of tuna, choose sardines, which would give us nutrient-dense food at a lower environmental cost. By eating less animal produce, we could afford to pay a little more, and choose animal products where the health and welfare of the animal is paramount.
Taking these steps would go a long way towards minimising the environmental and health concerns around eating animal products. Of course, many ethical considerations still apply, but respecting the life that has provided food by using the whole animal and ensuring that it has the most stress-free life and humane death as possible, mitigates some of these. 
For those who choose to follow a vegan diet and lifestyle as well as those who still want to include high-quality and high-welfare animal products, both are available at True Food. True Food stocks an entire fridge of purely vegan products, and of course there are plenty of pulses, grains, nuts and seeds for vegans who would prefer less processed options. You won't get more choice under one roof!
* Statistical information taken from the Vegan Society website.