So I started Keto 3 weeks ago and since I've put on 3 lbs but my body fat percentage has changed, is this normal?
Long term, I would say a Keto diet would be the least productive diet to be on if LBM gains were your goal.
Since your post is so vague that's about all I can tell you at this point.
Lotta things could be going on. I wouldn't put money on muscle gain though, Keto diets keep your insulin levels pretty tanked, which isn't the best environment hormonally for hypertrophy. Besides, no one gains 1 lb of muscle per week unless they're loaded up on PEDs. I hate to get a bit graphic, but are you eating enough veggies for fiber? Could you be 'backed up?' My weight fluctuates 4 lbs during the day simply from water and food.