Why I am a Vegan

[Diana]

Eating lower on the food chain has many benefits, both physically and energetically.

The below is from Explorit Science Center science facts

Do biological processes rely upon a supply of energy?

Yes. Both plants and animals are absolutely dependent upon energy for growth and movement and for the maintenance of basic function and structure. If energy intake drops below the amount required for maintenance, an organism consumes its own energy stores until those are exhausted and the organism dies.

Does all life on Earth depend upon radiant energy from the Sun?

With the exception of certain bacteria and algae which get their energy by the oxidation of inorganic compounds, and the animals that get their energy from these particular bacteria and algae, all life on Earth depends on radiant energy from the Sun.

How is solar (radiant) energy made available to living organisms?

Animals cannot use radiant energy but plants can. Chlorophyll molecules in green plants and algae absorb radiant energy (sunlight) and use this energy in the manufacture of glucose (a sugar). The radiant energy is now stored in the glucose molecule as chemical energy and is available to the plant for its growth and to animals when they eat plants.

Are plants the only source of energy for animal life?

Yes. Some animals (herbivores or vegetarians) eat plants and derive their energy from the chemical energy stored in the plants' complex carbohydrate molecules. Other animals (predators and scavengers) eat animals, or the remains of animals, who have eaten plants; so, ultimately all animal energy is derived from the radiant energy absorbed by chlorophyll molecules in green plants.

What is a food chain, and what does a food chain have to do with energy?

A food chain has everything to do with energy. It is a term used by ecologists for the transfer of energy from its usable source in plants (see Day 25) through a sequence of living organisms. This sequence starts with a plant-eating animal which is the source of food for the animal(s) above it in the food chain. 
a) Grasses manufacture complex carbohydrate molecules using solar energy (sunlight);
b) herbivorous animals eat plants in order to obtain that food energy; and 
c) carnivorous animals eat herbivores for their food energy.