We use sex for your metabolic equation to determine your calorie needs, and there are different equations for men and women. If your gender identity is not the same as your sex assigned at birth, and you have not started gender-affirming medications, select your sex assigned at birth, because it will most accurately reflect your metabolic rate. If you have started taking gender-affirming medications, first consult with your doctor what might be the best selection for you. If you’ve only been on your medications for a few months, you might want to select your sex assigned at birth, and update when you are further into your medical transition. If you’ve been on your medications for longer than a few months, your metabolism might be closer to your gender identity, especially as muscle and fat mass start to shift.
For best results, please consult your doctor.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6046513/
https://nutritionj.biomedcentral.com/articles/10.1186/s12937-020-00590-4