How can prozac (fluoxetine) cause weight gain?

It is possible: Fluoxetine is an ssri anti-depressant, anti-anxiety medication that can cause weight changes as a possible side effect. In most of my patients, weight changes have been minor. However, some patients report larger weight changes, including more significant weight gain or weight loss. If you are gaining weight and concerned about it, talk to your doctor.

Side effect: of the medication. In most cases the weight gain is minimal.

Decreases fidgeting: Some patients do gain weight. A lot of patients with depression have significant anxiety, and fidget all day long. This can burn 100 -200 calories daily. When they are well treated, no longer experiencing anxiety, and stop fidgeting, they may slowly put on 1 or 2 pounds a month because they are burning fewer calories. It's like no longer walking a mile daily while eating the same amount.

Maybe: Weight gain is listed as a possible side effect, but weight loss is listed too. Depression itself can also cause weight loss or weight gain.