Injecting insulin twice daily would mean administering mixed insulin with breakfast and the same type of mixed insulin before his evening meal. With a mixture, the fast component of the mixture would cover blood glucose levels over breakfast and evening meals, whilst the slower component would provide glucose cover between meal times.

Though only 2 injections, Carlos would have to eat at a similar time each day and ensure that his meal content was fairly consistent. As Carlos worked shifts, his mealtimes would vary from day to day, so he felt this would be difficult to adhere to.