I was on protein diet i was lose every week 3kg my diet plan included 5 meals a lot of vegetables , fish ,chicken,and beef 45min workout is it healthy?

Slow it down: Losing 3 kg (6.6 pounds) a week is a pretty rapid weight loss. If you have a lot (30+ kg) to lose, this rate may be ok. The frequent eating is good as is "lot of vegetables." The protein is ok, but ideally you would have a little fiber/carbohydrate, too. Calories >900/day. If a variety of exercises in workout, 45 min/day is ok. Slow down weight loss to maximize chance of permanent loss.