Plant sources of protein are preferable, as animal protein sources been linked to negative health effects from acne (see also here) to cancer, female infertility, infant sleep apnea, autism, crib death, and premature puberty. Meat has even been linked with a shorter life span. The presence of industrial carcinogens, xenoestrogens, arsenic, steroids and external hormones in animal fat and protein may be partially to blame. Plant protein consumption has been associated with a slimmer waistline and consuming a plant-based diet and may help rheumatoid arthritis, prevent cancer, and normalize puberty age in young women. Food is a package deal. You can’t get the protein in meat without the cholesterol, for example. Similarly, the best source of vitamin B12 is from supplements rather from animal sources.
See also the related blog post: Atkins Diet and Erectile Dysfunction