Selena Gomez posted emotional video response to body-shamers, saying her lupus medication caused her to gain water weight

• Selena Gomez said her lupus medication causes her weight to fluctuate.
• Steroids are a common treatment for lupus, but they can contribute to weight gain.

Selena Gomez said her lupus medication causes her weight to fluctuate.

Speaking on TikTok live on Thursday, the 30-year-old responded to comments about her weight gain by saying: "When I'm taking it, I tend to hold a lot of water weight, and that happens very normally. When I'm off of it, I tend to kind of lose weight."

She added she's "not a model" and "never will be."

She ended the video saying, "I don't believe in shaming people for their body or anything."

Lupus is an autoimmune condition

Lupus is a chronic autoimmune condition where the immune system can't tell the difference between foreign invaders and healthy tissues, according to the Lupus Foundation of America. It can damage any part of the body, including joints, skin, and internal organs.

Gomez announced in 2015 that she was undergoing chemotherapy for the condition and she had a kidney transplant in the summer of 2017, Insider's Leah Rocketto reported.

There are various treatment options for lupus including steroids that reduce pain and inflammation by decreasing the activity of overactive white blood cells.

However, one side effect of such steroids can be weight gain, as well as swelling and problems sleeping.

Lack of sleep can in turn contribute to weight gain by ramping up hunger and cravings.

Increased stress levels, comorbid diseases like hypothyroidism, complications caused by damage such as kidney issues, and related mood disorders such as depression can also lead to weight gain in lupus patients, according to MedicalNewsToday.

Obesity poses greater risks for women with lupus

Obese women with lupus may face greater health risks than the general population.

A 2011 study found that women with lupus are likely to experience obesity-related problems at a lower BMI of 26.8 — a BMI of over 30 is classed as obese, and over 25 is considered overweight.

Overweight women with lupus may therefore be at greater risk of conditions such as type 2 diabetes, heart disease, miscarriage, high cholesterol, hypertension, and respiratory problems, according to the Lupus Foundation of America.