These were purportedly all based on Bible scriptures, but often took scriptures out of context. ATI materials did a great deal of sub-texting, and expanded, explained, interpreted, illustrated and “wisdom searched” verses so far beyond and apart from the original text and context that it created an entire very complex counter-culture among those who followed its hundreds of extra-Biblical laws. Seven principles. 49 character qualities. Lots of wisdom booklets.
Basic Care Bulletins took general information about disease, preventative care, nutrition and health and mixed them in with Old Testament laws for Jews originally designed by God to show that righteousness by keeping rules was impossible. These were "cherry-picked" and applied out of context to modern Gentile Christians living in the dispensation of grace. This in turn led to a long list of dos and don’ts from what you could wear and not wear, eat and not eat, watch and not watch, listen to and not listen to, read and not read, think and not think.
I was born in 1969. Although I was homeschooled from 5th grade through high school, we did not personally use ATI materials. We did not join the BG movement, we weren’t an ATI family. (We wouldn’t have qualified even if we had wanted to. Small blessings.) I’m pretty sure we never even went to a Basic Seminar. And yet, the things that leaked out of that movement into the lives and doctrine of my family and my heart would influence me as much as if I had been right in the middle of it.