It was 1969 and Dick Bernstein was a 35 year old engineer who had been struggling with diabetes since he was twelve. He was married and had three small children, signs of a normal life, but he was concerned with his health. He had symptoms of many of the typical complications that diabetic patients face: poor vision, loss of feeling in his feet and lower legs. He was fatigued and irritable, causing problems with his family.
He wanted to solve his health issues. He thought like an engineer and understood his body as a system; it had certain inputs and these controlled the output. He could measure his inputs: his diet, the amount of proteins, fats, and carbohydrate he consumed each day, and the time he ate them, was easily recordable. He also knew the amount and type of insulin that he injected, and the time he made those injections. But the output he was concerned about, his blood sugar level, was a mystery. He could only measure his blood sugar once a month when he visited his doctor. He must have thought that it was like trying to drive a car down a road when you only get a peek at your surroundings once per minute.
Dick thought that if he could only control his blood sugar and keep it within the normal range, his health issues would disappear. His doctor did not agree. They pointed out that medical research had established that vascular disease was due to blood cholesterol levels. They thought that the most important thing for him was to be on a low fat, high carbohydrate diet. This diet, they reasoned, would keep his cholesterol values low, and eliminate or slow the peripheral vascular disease that he was developing in his legs. They also told him that keeping his blood sugar controlled within a narrow range was unnecessary and impossible to do.