frugivores eat not fruit alone but fruit and nuts/seeds, just for your information fruit is the most nutrient dense food after vegetables, 10 bananas have 1000 calories so what are you talking about? not sustaining? 100grams of ham have the same calories as one banana!
http://fddb.info/db/de/lebensmittel/...hter_schinken/
by the way our brain runs on glucose and plant eating animals have biggest brains carnivores have smallest..
you cannot get diabetic on fruits because they do not release sugar into bloodstream fast, they are optimal for us, diabetics are created by white sugar and white flour because they have high GI..
meat eating and dairy leaks calcium from bones makes arthritis osteoporisis cloggs arteries acidosis = cancer, creates mucus puts body into ketosis(state of clynical death)