Yes, you can. (Quick Start Guide to fat loss)

I have a question re: muscles. If you drop body fat and gain muscle do you still work with tdee? Sorry if its sounds a silly question but I wasn't sure if you had to eat more due to higher muscle mass or whether you just increase your protein. An example is from today. On a post a woman had started lifting, dropped body fat and gained muscle. She obviously had to be eating at a suplus to gain the muscle, which I understand. Her weight however is at 125 pounds now. Would she work out her tdee just the same as a 'normal' 125 pound woman? I understand with more muscle, metabolism goes up etc and always wondered if it was worked out differently.

Hi, yes you can always work with TDEE. Whether your body is made up of more muscle or fat its the energy it needs to move your body around. That said, you're right in that muscle burns more energy. Its like when you exercise and MFP says strength training burned 200 cals, its not quite the case as the recovery period of the muscle burns energy as well. For ease though I would just stick to TDEE.

As for the amount and please note this is my opinion and not fact!

For fat loss I work to -500cals per day under my TDEE. I do that while eating (fairly) clean, researching my macro breakdown, taking carefully timed BCAA supplements (to prevent muscle breakdown), drinking lots of water, green tea. Stopped alcohol (pretty much anyway) and so on. This allowed me to gradually lose fat while maintaining lean mass.

For muscle gain I'd do the same in reverse. Eat +500 cals over TDEE, same nutrition etc and Id hope to gain lean mass with minimal effect on fat gain.

So yes, whatever her weight now, no matter her composition she would use the same TDEE calculation (as I understand).