I lifted weights regularly and control my diet very well. now i'm very lazy and don't really want to go the gym. what can be the effect of this?

Hard to to answer. : Hard to answer in this format. There could be a physical, neurological, or emotional issue causing you to have a change in your determination to work out regularly. Probably best to talk to your family physician to determine the underlying cause. Good luck.

Are you depressed: well there is a reason your behavior changed mostly could be a depression are you upset or sad or something happen to make you feel depressed if not that physically there is no reason for the change see your doctor might be able to help you thank you for using health tap good luck

Depression: It is very easy to miss signs of depression. Please get some support and help from family. If not see a psychologist. stay connected with people who uplift you and motivate you. Stay away from those that are negative and lazy as well. You need high energy and loving souls to make you feel better.