What should I answer in the interview about the years I have wasted?

If you really just were laying on your back the whole time, and you absolutely cannot imagine any sort of organized activity you were engaged in, the only option you got is to openly admit it and clearly explain the reason why that happened.

Do find something you did in the years. Wasted time out of a job is one of the most negative things a candidate can have on an interview report.

Maybe you did some work at home? Had some hobby non-comercial projects? Studying is OK too.

If you really just were laying on your back the whole time, and you absolutely cannot imagine any sort of organized activity you were engaged in, the only option you got is to openly admit it and clearly explain the reason why that happened. The main concern of the recruiter in a situation like this is: “he did nothing for three years, but he’s looking for a job now. Why? He’s out of money? He’s got alcohol/drug problem? What will happen if we hire him, will he look to go back to the easy life he’s had?”. Basically, a recruiter would doubt your motivation mostly.

So, the countermeasure is to accent and to be really convincing about your motivation to work in a career or at a particular country. Try to look as active and inspired as possible, openly state, that after a long time of searching, you are totally and positively sure that this career is for you and you are strongly determined to follow this career path from now on.