Lemon, 30, built a shed, hired a coach and worked towards a bodybuilding contest in Maidenhead - which he won. Now he is excited to see what else he can achieve in the sport.
His next show, as things stand, will be at the NEC Birmingham in October, The Arnold Classic, at which he will compete in the beginners' category.
Lemon, born and raised in Rye, East Sussex, said: "My life changed in lockdown. Last year I had no motivation for anything. The first lockdown put me in a bad place and all I did was drink and sit at home depressed there was nothing to do.
"Things were getting bad for me as the only thing I loved was working and training in the gym and I couldn’t do either at this point and my mental health wasn’t at its best.
"Then going into December I thought 'I can’t go through this again'. I can’t let my life keep going out of control and drink and drink and feel sorry for myself. So I built a shed in my garden out of any materials I could get together, bought some weights and started my journey to a better me.
'I took on a coach called Jason P Long, aka Jase. I told him I wanted to better myself and we needed a plan. So he gave me a plan and I stuck to it! A few weeks in, a show had been announced - the biggest bodybuilding federation in the world the IFBB 2 Bros Pro Events Ryan Terry Classic. So we thought... 'Let’s do bodybuilding for first timers - let’s have a go!
'So I did 90 minutes' cardio a day, one hour training , six meals a day and plenty of sleep. This was very hard. It isn’t an easy process but I knew I needed discipline!
"Finally last month I competed in London and I took the win - first place, and a place in the pro qualifier.
"This lockdown didn’t take any happiness I had left in me. I worked through it and had a goal to reach and I did it! I have motivated hundreds of people for doing this and the messages and comments I have had on Instagram have been amazing from people as to how I have changed their metal health and got them motivated.
"I am going to help as many people as I can now to get to the bottom of their problems and help reach their goals because we can’t let people go on not being heard and living in a dark life."
Lemon's partner Daisy Mills said: "Adam had been suffering with mental health and was in a bad place, binge-drinking, but this last lockdown really helped him. He trained and dieted hard from Christmas to compete in his first ever competition. He built a gym in his garden with equipment given to him by friends. He trained so hard - in the snow, rain and sun. He dieted the whole of lockdown, then stepped on stage and won the first-timers' category."