The personal trainer, 25, who appeared on season 10 of Love Island earlier this year, said he felt he was 'arriving at the villa, making him feel blue'.
In an exclusive interview with MailOnline, Zachariah candidly shares his body transformation and what he does to stay in his best shape.
He said: 'On Love Island I had more difficulty finding a routine, it was much harder to stick to my usual routines.
'I felt like I was gaining weight while losing my routine, and in some ways I feel like it reinforced my past experiences where I felt down. But I never had the time to compare myself, just be happy with who you are.
Zachariah Noble, 25, has admitted he felt his 'mental health deteriorated' on Love Island because he 'lost his routine', following his dramatic weight loss
'You'll never be able to please everyone and you can't spend your whole life trying to please other people. It's more self-happiness.'
Zachariah also shared that he “avoided nights out, sacrificed processed foods and cooked everything from scratch to be disciplined” and stuck to a consistent routine to lose weight.
He added: “For me, the hardest part was the initial adjustment phase. Find discipline and follow it.
“I cut out processed foods, cooked everything from scratch, sacrificed a lot of things.
'I went out a lot less, hung out with my boys a lot less and only prioritized the things I felt like I needed to do, which was being at home to prepare my meals and avoiding nights out.'
The reality star also admitted he would like to sign up for Celebrity SAS and Celebrity Hunted 'to push himself to the limit'.
He continued, “New Year is coming, so what better time to set your goals straight. A good time to structure a real plan and be consistent with it.
'I would like to push myself to the limit and show people what I do and try to inspire people.
Zachariah, who appeared in season 10 of Love Island earlier this year, said he felt he was 'arriving at the villa, making him feel low' (pictured with Charlotte Sumner in the show)
He said: 'On Love Island I had more difficulty finding a routine, it was much harder to stick to my usual routines. I felt like I was gaining weight while losing my routine, and in some ways I feel like it reinforced my past experiences where I felt down.”
Zachariah also shared that he “avoided nights out, sacrificed processed foods and cooked everything from scratch to be disciplined” and stuck to a consistent routine to lose weight.
The reality star also admitted he would like to sign up for Celebrity SAS and Celebrity Hunted 'to push himself to the limit'
Meanwhile, Zachariah discussed how his girlfriend Molly Marsh (pictured) has helped him stick to his weight loss goals since they met in the villa in the summer.
He shared, “I think there are pros and cons. When you're in a relationship you eat out more often, but she understands my goals and helps me achieve them.'
“When many people focus on being the best version of themselves, the world becomes a better place.”
Zachariah discussed how his girlfriend Molly Marsh has helped him stick to his weight loss goals since they met in the villa over the summer.
He shared, “I think there are pros and cons. If you are in a relationship, you go out to eat more often. It's easier to lose yourself, but your partner understands what you're trying to achieve.
“I would say it's definitely positive because she understands my goals and helps me achieve them.”