In fact, we would know ourselves that we are not meant to be meat eaters, and we would not have allowed ourselves to become conditioned to meat eating in the first place, if the effects of meat eating were felt right away. But since heart disease, cancer, diabetes, osteoporosis, etc. usually take many years to develop, we are able to separate them from their cause (or contributing factors) and go on happily eating an animal-based diet.
Sharon Gannon