“How much do you weigh?”

It’s a simple question, but it’s a sensitive one, too — whether you’re lean, overweight or somewhere in between. Weight is a thorny subject for many of us, and talking about weight loss can be even trickier.

But high weights are consistently associated with long-term health problems, leading to higher insurance rates for the overweight, so many companies find it’s an important subject to address. Some businesses implement a weight loss program to promote overall employee wellness and encourage healthy habits at the office.

If you’re likewise tackling weight loss in your workplace, keep these tips in mind to help you stay sensitive and ensure a positive experience for employees.

Don’t Oversimplify

Sure, if you eat less and exercise more, you should drop the pounds. But as anyone who has dieted can attest, the experience is nowhere near that simple.

The New York Times recently profiled former contestants from the reality TV show “The Biggest Loser,” noting that while these people lost massive amounts of weight, most found themselves unable to keep it off.

Why? In almost every case, their metabolisms slowed down dramatically after their weight loss. Former contestant Danny Cahill now burns 800 fewer calories per day than what would be expected for someone of his size. That means the same lunch that keeps his similarly sized co-worker fit and trim might make him gain weight.

There may even be factors that don’t have to do with energy intake and output. According to Scientific American, recent research indicates that our gut bacteria can impact our body weight. If this is the case, someone with bad gut microbes who is trying hard to lose weight may find themselves frustrated, while someone with a better bacterial profile could simply give up their morning latte and watch the pounds fall off.

The takeaway? Weight loss is more than a math problem, and the way you discuss the topic with employees should be sensitive to that complexity.

Draw Clear Lines

Wellness programs can make a difference in productivity and engagement, but that doesn’t mean you can use weight loss or health improvement as criteria for employee evaluation.

Avoid being judgmental, and don’t pressure anyone into signing up for the company weight loss program. Managers should never be held accountable for how many of their employees meet wellness goals, and no supervisor should ever follow up with an employee to ask why he or she isn’t participating in the program. Employees should never feel like they’re being judged based on their waistlines instead of their job performance.

Don’t Equate “Thin” With “Healthy”

Carrying excess weight comes with health risks, but being too skinny can also be bad for your health, the Harvard School of Public Health notes. Someone who looks great can have underlying problems while a heavier individual might actually have better health markers. Plus, excessive weight loss can reflect a range of health issues, from smoking-related complications to eating disorders.

Don’t Overemphasize the Scale

Try not to talk about weight as much as you do about health. Medical News Today notes that body mass index can be a flawed measure of health because it doesn’t distinguish between fat and lean tissue. Someone who loses fat and adds muscle could become healthier with little to no difference occurring on the scale.

Consider encouraging goals that don’t have to do with weight loss per se but rather reflect improved health, such as completing a road race or going to the gym four times a week for one month straight.

Appoint a Qualified Leader

If at all possible, the person who heads up your company’s weight loss program should be someone with a background in health. In many cases, it will be much more effective to bring in someone from the outside. You don’t want people to have to stand on a scale and have their weight recorded by their boss, co-worker or direct report.

Additionally, if an employee’s weight loss behavior is unhealthy, someone with expertise will be better able to tell that person that he or she is already too thin or needs to keep weight loss to one or two pounds per week, per the recommendations of the Centers for Disease Control and Prevention.

Keep Rewards Fun and Fair

Giving a reward to someone for losing the most weight in a month can lead to unfairness and hazardous weight loss. Use some creativity to think of more positive ways to help employees achieve their health goals. For example, you could create teams and reward the group with highest combined number of steps logged on their Fitbits.

Also, keep rewards unrelated to work. Offer a gift certificate to a healthy lunch spot instead of a bonus. There should be complete understanding that the weight loss program has no impact on compensation.

One last caveat: No one should start a weight loss effort without a doctor’s approval. If it’s an official, company-sponsored program, spring for the cost of a physician review to keep your bases covered.

If you’re able to use these tips to keep conversations about weight loss encouraging, affirming and sensitive, your program will be off to a solid start.

Suzanne Lucas spent 10 years in corporate human resources, where she interviewed and hired employees, managed the numbers, and double-checked with the lawyers. Her writings have appeared in Inc. Magazine, CBS MoneyWatch, US News, Readers Digest and other publications. She focuses on helping businesses nurture great employees and helping employees enjoy great careers.