As well as following a Weight Watchers plan, Dawn has stopped eating meat and dairy products. She no longer wears leather and uses environmentally-friendly products around her home.
Dawn, 56, of Park Road, Barnsley, weighed 17 stones and eight pounds at her first weigh-in in April last year.
She was inspired to follow a vegan diet by her children who had been vegan for about two years.
She said: “I turned vegan when I joined in April last year, but my children had been vegan for a couple of years so I had been cooking vegan at home for that period.
“But I started to look further into animal welfare and just felt I needed to follow that road. It became important to me what happened to animals.
“I have completely changed my lifestyle. It was about getting my life and health in order.”
Dawn lost so much weight that when she had her gall bladder removed in September, she needed reassessing before the procedure.
Her diet has also had a knock on effect on her husband who has lost two-and-a-half stones.
Dawn said: “I don’t miss meat at all. There are lots of meat replacements, but to be honest I would rather make something with fresh ingredients. It’s easier and makes you look it what you are eating. It also tastes better. We’re so used to eating processed foods that when you stop, your body adapts and you start to taste real flavours again.
“I feel loads better. I’m not quite yet at my goal weight, I need to lose another two stones. Those two stones will probably take as long to lose as the first five.”
Dawn said Weight Watchers had been so fantastic for her that she chose to become a coach. She runs a Weight Watchers group in Sheffield and is hoping to start one in Barnsley in coming weeks.