Vegetarianism
Hills was the first president of the London Vegetarian Society, founded in 1888, and served on its executive committee with the young Mahatma Gandhi. He was also the first president of the Vegetarian Cycling and Athletic Club and president of the London Vegetarian Rambling Club. He founded The Vegetarian, an independent periodical, and the Vegetarian Federal Union in 1889, of which he was also president. He founded the Oriolet Fruitarian Hospital at Loughton, under the medical direction of Josiah Oldfield.
In an article titled "Milk and Eggs", Hills described milk, cream, butter, cheese, and eggs as "props of a transition period" rather than part of the vegetarian ideal. He argued that milk and eggs were foods naturally intended for young animals and human infants, and that adults should move beyond them. He criticised the use of milk, cream, butter, and especially cheese on physiological grounds, claiming that cheese was made indigestible by fermentation. Hills also rejected eggs as less digestible when cooked, and said that reliance on milk and eggs was justified only by social convenience. He urged vegetarian "experimentalists" to replace them with fruit, nuts, and grains.
In 1892, Hills authored Vital Food, in which he argued for a plant-based raw food diet.
