Think twice before rejecting job applicants just because they are obese. That's the wise advice of many experts who recommend that employers proceed cautiously despite a recent appeals court ruling that backed an employer's rejection of a job applicant because of his obesity.

In its April 5 ruling in Melvin A. Morriss III v. BNSF Railway Co., the 8th U.S. Circuit Court of Appeals in St. Louis held that an obese job applicant, whose obesity apparently was not related to any physiological condition such as diabetes, was not protected from discrimination under the Americans with Disabilities Act.

According to the ruling, Mr. Morriss was offered a job as a machinist with the Fort Worth, Texas-based railroad that was contingent on a satisfactory medical review.

But the job offer was withdrawn after medical exams revealed he had a body mass index of more than 40, which was above the railway's standard for the measure of body fat based on weight and height.

Experts point out the ruling is significant because it is the first appeals court to rule on the issue since enactment of the Americans with Disabilities Amendment Act of 2008.

Two previous appeals court rulings had similar findings to the recent 8th Circuit ruling, but both were issued before the 2008 law that broadened discrimination protection for individuals under the ADA.

Experts warn, however, that the legal landscape remains unclear. Furthermore, and perhaps more significantly, the 8th Circuit ruled the employer could reject hiring Mr. Morriss because there was no indication his obesity was caused by an underlying physiological condition, and it is not clear how often that is the case. The U.S. Centers for Disease Control and Prevention, for instance, says it has no data on the subject.

Clearly, however, obesity often is related to underlying health conditions. A report issued last week by Chattanooga, Tennessee-based Unum Group, for instance, said the fact that more than one-third of U.S. residents are overweight is a major factor in the significant jump in disability claims for joint disorders and musculoskeletal issues in the past decade.

The bottom line: The safest bet for employers is to continue doing what they have been doing — hire the best person for the job, regardless of how much they may tip the scales.