This gets talked about a lot so here are some hard numbers in my experiment of one.
Start Jan 15
Height 71"
Weight 205 lbs
BMI 28.6
Bodyfat 26% (Measured as Male)
Fat weight 53 lbs
Lean weight 152 lbs
Now Apr 16 (14.5 months HRT)
Height 71"
Weight 160 lbs
BMI 22.3
Bodyfat 14.3% (Measured as female)
Fat Weight 23 lbs
Lean Weight 137 lbs
Change
Height None
Weight -45 lbs
BMI -6.3
Bodyfat% -12%
Fat Weight -30 lbs
Lean Weight -15 lbs
The body fat % measurements are pretty accurate I think. The original one was by a body fat impedance scale. The current is by body fat impedance scale confirmed by calipers. The scale and calipers differed by only .24%.
From Jan through May last year I dieted and ran to get in shape. I continued running through Aug without diet. Then I got lazy and did nothing until this Jan. in that time I gained some weight back up to about 178.
Since the beginning of Feb I have been dieting and exercising heavily and have lost about 18 lbs. Since Feb the diet is a 1000 cal daily deficit (that is higher than generally recommended). The exercise program is a lot of walking, about 25 miles running per week, abs work 5 days a week, and body weight exercise 3 days a week. Currently I'm up to 200 sit-ups, 100 push-ups, and 100 squats. The big irony of all this is that I have a 6 pack for the first time in my life and I got it on HRT.
Other than that HRT alone has taken care of muscle loss although I lost so much fat it's hard to say exactly what was fat loss and what was muscle loss in any particular area.
As far as body feminization goes I have gotten to a lower body fat level than ideal. My ribcage measures 36" and my bust 41" and they look really small to me. They were bigger back in Jan by nearly 2". I have other motives though in wanting to run well and find my "ideal" running weight. Regardless, after I lose 5 more pounds (12% BF) I'll probably allow myself to gain some back and hope it goes to good places. I'll be able to gain up to about 25 lbs and remain in the "healthy-fitness" BF category <24% if my lean mass doesn't change much further. Maybe it will though; I'll have to wait and see what more HRT does there.
Lastly, weight loss IS NOT harder on HRT. At least no harder than before HRT. In both cases it sucks but it will happen with a calorie deficit.
Sapere Aude