[yes_man]

There are indeed people who have medical conditions that make their life dangerous with a plant-based diet. For people without such conditions (the majority of people), science on negative effects of plant-based diet seems to focus on certain deficiencies (such as deficiency of zinc and iron, or omega-3 EPA and DHA fatty acids). These deficiencies can be avoided by consuming specific plant-based sources, such as certain seaweeds for EPA and DHA.

For most people plant-based diet is probably completely safe and when debating this issue, the bottom argument of opposition to plant-based diets usually boils down to one thing: the god-given right or even necessity for man to eat other animals (be it because of it being natural to eat other beings in nature, because "plants have feelings too", or because of traditions or humans dying if they don't eat meat). This rests on ignorance of science, self-centered attitude and violence. Industrial-scale animal production for food is an abhorrent machine by any humane moral standards and most people use these counter-arguments because they like how meat or cheese tastes and they want to close their eyes.

Hunting or fishing or growing your own meat is much less evil than the animals-for-food industry but the nature ecosystem could never sustain current amounts of meat consumption. Also it has to be understood that in developing countries masses of people cannot afford to be fancy about what to eat and what not. In developed countries however... I think we should not consider ourselves "developed" if we kill 10x our own human populations amounts of animals each year for food based mostly on the fact that we are used to it and that meat tastes good. As more and more people realize this, the demand for plant-based diets goes up.

[chukye]

Nice discussion folks.. BUT, there is an argument that never makes sense to me "the nature ecosystem could never sustain current amounts of meat consumption", so how can nature sustain amounts of PLANT consumption IF we all change it to plant-based diets? This does not make sense since for 1 piece of meat we need to eat dozen of different plants; plants as food have a huge impact in nature too.

[throwaway20201]

Your logic breaks down when you consider the fact that humans will never consume as much plant matter or water as livestock.

In fact, the creation of meat is a wasteful process, requiring up to 25kg of grain and 15,000 litres of water to produce 1kg of steak. [1]

1: http://waterfootprint.org/media/downloads/Report-48-WaterFoo...

[yes_man]

The animals eat a lot more plants for a pound of meat they gain than humans would need if we only ate the plants. We are in the first day of this year and already over 120 million animals have been killed in the US for food. Approximations on amount of animals killed each year for food in the USA vary, but it is in tens of billions. Can you imagine the strain natural ecosystem would need to sustain to support tens of billions of new animals every year? We are already on the edge when feeding those animals with industrial crops.

[burfog]

Humans are not ruminants. We can not survive on hay. We can survive on the high-nutrition parts of plants, but creating these parts is resource-intensive. In some cases the whole plant is simply difficult to grow (pests, fertilizer, etc.) and in other cases we don't get very much food from each plant.

There is a whole lot of tree attached to a cashew.

Goats and sheep are happy to eat the weeds on a rocky hill, and cattle do almost as well.

Other food animals are happy to eat disgusting waste. Pigs, chickens, and catfish are especially willing.

[danans]

> There is a whole lot of tree attached to a cashew.

There is also a whole lot of cashew attached to that tree, and the same tree produces more, year after year.

[chukye]

Exactly! Humans to survive need to combine a lot of fancy vegetables, we can't live eating grass...