I assume by "keto" you mean low-carb?
if so, be sure to take a good multi-vitamin every day. Everyone's a little different. But for me, a day or two in, my appetite pretty much goes away. Most days, my breakfast is a meal replacement drink made with almond milk and dark chocolate cocoa (the baking kind, with no sugar)...I also have a handful of almond nuts. Lunch is a piece of cheese and handful of almond nuts. There are lots of low-carb recipes online too which I reserve for my dinner mostly.
For reference: I am 6' tall and was 260 on February 1... I am currently about 190 and aiming to be under 170 before I start HRT.
For me it will be a lifestyle change where I limit carbs such as potatoes or any kind of fast food to just once a week. (once I am below 170)
you can do it!