All about fruitarianism with a long-term fruitarian, Lena

Leaves and stems of plants, green vegetables or leafy greens, are widely consumed by humans. The protein contents are higher than in fruits, and they contain low amounts of sugar.

Some green vegetables produce secondary metabolites that have bitter or astringent properties and may produce toxic alkaloidal and other compounds such as hemoglutenens. Others produce intestinal enzyme inhibitors, such as lectins, which bind to mucosal surfaces and inhibit digestion, especially that of proteins. 


Plant secondary metabolism produces a large number of specialized compounds (~ 200.000) that do not aid in the growth and development of plants but are required for the plant to survive in its environment. Specialized compounds from secondary metabolism are essential for communicating with other organisms in mutualistic (e.g. attraction of beneficial organisms such as pollinators) or antagonistic interactions (e.g. deterrent against herbivores and pathogens). They further assist in coping with abiotic stress such as increased UV-radiation.

The broad functional spectrum of specialized metabolism is still not fully understood.

Well known specialized compounds include alkaloids, polyphenols including flavonoids, and terpenoids. Humans use quite a lot of these compounds, or the plants from which they originate, for medicinal and nutraceutical purposes.

John Stuart Mill

A person may cause evil to others not only by his actions but by his inaction, and in either case he is justly accountable to them for the injury.

Seeds

Seed is an embryonic plant enclosed in a protective outer covering. The formation of the seed is part of the process of reproduction in seed plants. Seeds have been an important development in the reproduction and success of gymnosperms and angiosperms plants, that now dominate biological niches on land. 

The term "seed" also has a general meaning of anything that can be sown, e.g. "seed" potatoes (tubers), "seeds" of corn or sunflower "seeds". 

Many structures commonly referred to as "seeds" are actually dry fruits. Different groups of plants have other modifications, the so-called stone fruits (such as the peach) have a hardened fruit layer (the endocarp) fused to and surrounding the actual seed.

Nuts are the one-seeded, hard-shelled fruit of some plants with an indehiscent seed (acorn, hazelnut).

Fruitarians.net Apple