At her heaviest she was 16 stone and 2 pounds, and despite trying fad diets, Caroline from Irvine, Ayrshire, couldn't stick to a regime for longer than two weeks and became even more miserable.
Her turning point came when she overheard a friend talking about leftovers, saying that "Caroline would hoover them up".
"I was mortified, I nearly broke down in tears there and then. I knew I was big but didn't realise what other people thought of me - especially what I considered to be a friend."
At her heaviest Caroline gorged on almost 4000 calories a day getting through six rounds of white toast, two packets of crisps and snacking on cake and ice cream.
As a result she reached a dress size 18 and became even more miserable, resorting to comfort eating.
When she went on her first foreign holiday in May 2013, she dreaded what to wear and settled for covering up as much skin as possible.
Caroline said: "Whenever I did wear anything showing a bit of skin, I felt so uncomfortable like everyone was staring and laughing.
"When I got home I looked through the pictures and couldn't believe they were me. I knew I was big but I looked horrible. The main reason I'd gained so much weight was my teenage party girl years.
"Every weekend I'd go out, binge drink and wolf down takeaways, pizzas and burgers were my favourite."
As soon as the New Year came, a determined Caroline bought a cross trainer and returned to a healthy eating regime.
But after a month of dieting, she started to get bored, but this time, instead of quitting, she signed up to the Cambridge Weight Plan.
With the help of her consultant she swapped dinners of macaroni, chips and garlic bread for chicken breasts, veg and sweet potatoes.
In place of oil drenched packets of crisps and sweets for snacks, Caroline now grazes on apples and grapes.
A newly energised Caroline said: "After my first week on Cambridge, I lost a massive 7lbs. I realised this was the diet for me and I just kept dropping 5lbs or 3lbs each week.
"At the start I was doing light exercise, but as I increased the amount of food I ate I started to introduce more. Now I'm fitter than ever and have found a sport I really love - running - which I never thought I'd say!"
Caroline's Diet Before
Breakfast - 4 slice of white bread toasted with butter.
Morning snack - 1 or 2 packets of walkers crisps.
Lunch - Noodles and 2 slice toast with butter.
Afternoon snack - Handful of sweets e.g. Haribo etc.
Dinner - Macaroni, chips and garlic bread.
Pudding - Ice cream or cake or both
Caroline's Diet After
Breakfast - Porridge
Mid-morning snack - Apple
Lunch - Homemade butternut squash soup with wholemeal roll.
Afternoon snack - 130g of grapes.
Dinner - Chicken breast, sweet potato and veg.
Supper - One slice of wholemeal toast with low fat spread