Before Atkins, there was Bernstein. He was a Ph.D. controls engineer in the 1960s who had Type 1 Diabetes, and was very fragile (experienced side effects if his insulin for a meal was too much or too little).
For some reason the American Diabetes Association changed its diet from low carb to high carb, and Bernstein had trouble keeping stable. When his friend at the University obtained a new instrument that measured blood sugar, Bernstein talked him into allowing him to use it. He ate various foods, and then tracked his blood sugar for the next 4-6 hours, and then used his controls background to analyze the data.
His primary conclusion was that small errors in estimating carbs in a meal should lead to small problems. For example, a cup of salad contains 10 carbs with plus or minus 2 carbs estimation error -— and within tolerance of his body’s reaction to insulin; but, a cup of pasta contains 300 carbs plus or minus 20%, which is 60 carbs, which is not within insulin tolerance. He thus concluded that a low carb diet was safer than a high carb diet.
He wrote up his results in a book, “Dr. Bernstein’s Diabetes Solution”. He took it to book publishers, and they told him no diet book could be published unless it was written by a Physician.
Between his zeal to tell other diabetics of his solution, and his anger as being told no one would publish his book because he was a Controls Engineer, not a Physician ... he quit his job and enrolled in Medical School to become a Physican.
For his Senior Thesis, he updated his book. When he graduated, he returned to the book publishers, and convinced one of them to publish his book, now written by a Physician.
My hat is off to him ... he was a man.