Paula Muir and her identical twin sister, Karren Fraser, have always been very close.
"We're competitive, but always encourage each other," said Muir. "We always show massive support for each other."
That support and competitiveness helped the sisters, who are 46 and live in England, to achieve a remarkable goal: between them, they lost more than 300 pounds. Muir lost about 140 pounds.
Fraser had an easier time losing weight, since she opted for gastric banding surgery, a procedure that involves placing an adjustable band around the top of the stomach. The result is that the person feels full more easily and eats smaller portions of food, leading to weight loss.
"I couldn't get a gastric band because I didn't have the money," said Muir. But she was determined not to let that get in the way of her weight loss goal.
I didn't want to be the fat twin," she said. "After all, we're twins, so we have to look alike."
Thanks to her competitive spirit and the support of her sister along the way, Muir disciplined herself to eat the same-size portions as her sister did. She knew she wouldn't lose quite as much weight as her sister, but was determined to keep it close.
"It was so hard for me," Muir said. "She had to stop eating because of the band, but I could eat. I had to say no and tell myself I need to cut down."
Muir said that her sister's support was vital in the two-year quest to lose weight. She said she couldn't have done it without her sibling by her side, and experts say family members and friends provide the push people need to achieve their weight loss goals.
"It gave her the motivation and told her that if she eats the same amount, she should be able to lose the same amount of weight with everything else being the same," said Keith Ayoob, director of the nutrition clinic at the Rose R. Kennedy Center at the Albert Einstein College of Medicine in the Bronx, N.Y.
"It can be very helpful, especially if they spend a lot of time together," said Carla Wolper, nutritionist and clinical dietician at The New York Obesity Research Center at St. Luke's-Roosevelt Hospital Center in New York. "They could trade recipes and exercise together."
Fraser and Muir ate most of their meals together, and when they went out, they shared a meal. Muir ate a little more, but rarely ate more than that one shared meal.
"She'd constantly remind me to chew and put my knife and fork down," said Muir.
The sisters committed themselves to losing weight after visiting their dying father.
"My dad was worried, even though he was dying," said Muir. "He was always fit and healthy."
Muir also said she and Fraser had been depressed about their weight and as they got older, worried about their future health.
"I thought that if I don't get slim now, I'm going to be old and fat with health conditions, and it's going to spoil things."
Doctors say now that the women have lost all that weight, the real challenge begins.