What the LAW says is you do not have to tell them you have diabetes untill after they offer you a Job and you have the Medical exam. See below;
ADA and LAW Enforcement
[1. Q: Who is a "qualified individual with a disability" for employment?
A: A qualified individual with a disability is an employee or job applicant who meets legitimate skill, experience, education, or other requirements of an employment position that he or she holds or seeks. The person must also be able to perform the "essential" (as opposed to marginal or incidental) functions of the position either with or without reasonable accommodation. Job requirements that screen out or tend to screen out people with disabilities are legitimate only if they are job-related and consistent with business necessity.
2. Q: The ADA prohibits making disability-related inquiries or giving applicants for police jobs medical examinations until a conditional offer of employment is made. Why?
A: In the past, people with disabilities, particularly those with hidden disabilities, were denied jobs once potential employers found out about their disabilities. The ADA seeks to prohibit discrimination by limiting an employer's knowledge of an applicant's disability to a later stage of the job application process. Under the ADA an employer may only ask about an applicant's disability or give a medical examination after the employer has made a job offer. The job offer can be conditioned on successfully passing a medical examination. Thus, if the person with a disability is denied the job because of information obtained from the medical examination or because of the applicant's disability, the reason for this decision is out in the open. This procedure should limit impermissible consideration of disability.
