I've actually been prepping for the possibility of transition myself via diet and exercise. I'm close to 5'9 and was around 162 lb's and over 10 months I dropped to 129. I've since gone up to 136 but it's largely muscle.
I started with a ketogenic diet for two months and drooped to 145 doing that. I'm not a big believer in it for long term usage so it was a one time thing for me. After that I switched back to eating carbs but with an intermittent fasting (IF) plan. Basically I eat my food in a 3-4 hour block every other day with the middle day being two meals at different times to prevent my body from getting adjusted to it. Sometimes I'll do IF twice or three times in a row too just to keep it random.
If you want to do Ketosis, go for it, but honestly I'd only recommend it to people who are very much overweight as it seems to be more effective in that scenario.
Doing IF and paying attention to my caloric intake (vital might I add) I was able to drop to the 129 range.
I started going to the gym when I was around 135 and kept things pretty simple, but now I eat from 2-2.5k calories in days I work out in order to add muscle. A lot of women here want to avoid muscle but I think if you do it right, the results can be very, very pleasing.
What I've done is focus entirely on my lower body in the gym since that's where women tend to be larger. I've developed a nice rump out of the process that I assume will be aided by fat distribution to the thighs and butt region if I start HRT. Women develop muscle a bit different too but not so much that it's going to be a big deal. Basically I can already see the framework for an appealing lower half. My belly region has been getting flatter with time as well. My primary method of exercise is squats, calf raises and low back extensions. Throw in lunges too to switch things up. Squats should ALWAYS be a focused exercise though. They are amazing for your body.
I do this every four days. In the middle I will do a workout at home consisting of pushups, dips and curls in order to exercise my arms and chest. The reason I'm doing this is because they aren't going to result in insane muscle gains, especially since I'm not going overboard on calories on these days. I'm toning them though and yes, I've gained some mass but not so much that I look ripped or anything. High repetition of low weight tends to not equate to mass and strength. That said, I fully expect HRT will take my upper body muscle gains out of the equation over time due to the deterioration that is typical of the upper body with estrogen + blockers. My hope is the results will be a feminine but athletic appearance.
HRT is a slow process and it takes patience. You won't see results magically overnight and often takes up to a year to really see the difference in your face and overall body hair (if you have any). So since it's slow and I know I won't magically pass right away I'll let the HRT decay my upper body.
Another reason I'm going "hard in the paint" with lower body is because I want to take advantage of testosterone while I have it in abundance. It's simply easier to gain muscle this way and I want to have a toned, look. Muscle also increases your metabolism which means I burn my body fat easier. I'm going as low as possible so if I start HRT I can pile on fat in better locations for a more visible impact.
^ the power of squats and lunges.
NOW, if you're NOT going for that look and simply want to be totally skinny (which is perfectly fine) everyone has their own preference for how they want to look. If that's what you want, focus heavily on diet, via caloric intake (you still do this with the other way too). Try to eat whole grains, brown rice, oats, etc if you're eating carbs. Mix in lots of greens and some fruit here and there. Then hit the cardio. That's the big change from the lower body muscle path. Cardio will eat both your fat and muscle. Do consistent cardio though and for a long period of time. If you do High-Intensity Interval Training (spurts of sprinting then jogging for a shorter amount of time) you will likely gain muscle in your legs. Only do HIIT if you are going for the rump rout.
I learned a lot about this stuff when I was trying to get all ripped to be a manly man. That didn't really work out.
So to sum it all up since I wrote so much, haha.
1. Watch your Calories like a hawk.
2. Good food = Good results
3. Use Testosterone to your advantage while you still can, IF you want to.
