Lisa Riley shed 12 stone after becoming "addicted" to losing weight.
The "Emmerdale" star - who is to reprise her role as Mandy Dingle in the new year after 17 years away from the Dales - admits her life was "filled with self-loathing" until she shed some pounds, but when she started fitting in smaller sizes she couldn't stop trying to slim down.
She said: "I was obese, had a dreadful diet, drank too much and was filled with self-loathing. I was a complete over-eater and an emotional eater. I'd eat when I was happy and eat when I was sad.
"I decided that instead of feeling sorry for myself and making up excuses, I had to do something about it and turn those negatives into positives.
"And, believe me, once you start seeing results it becomes addictive.
"As my dress sizes started to drop and my choice of clothes grew, it spurred me on to keep going."
The "Three Girls" star admits she was a "classic over-eater" and says she couldn't resist chowing down on a three-course meal on a night out during her larger days.
She said: "I was the classic over-eater but I have completely changed my attitude towards food
"I used to go out for a meal and have a starter, main and pudding. No wonder I was gaining weight."
The 42-year-old actress has recommended people to abstain from alcohol and cut out carbs if they want to shed some stone, admitting both really helped her slim down.
She is quoted by the Daily Mirror newspaper as saying: "Alcohol is just empty calories. I know cutting out the booze had a massive impact on helping me to shed the pounds.
"Even if you can stop boozing between now and December, when the parties all start, it will give you a huge kick-start."
This comes a day after Lisa confirmed she is heading back to "Emmerdale", and she cannot wait to see what Mandy gets up to in the new year.
She said: "I could not be happier to be returning in the new year to Emmerdale. It's something I never thought would happen after 17 years and I am so interested to see what trouble Mandy is capable of causing.
"But mostly being back with all my old friends, it's like I've never been away."