Diet programs come in all shapes and sizes. 

Elizabeth Tucker, who has struggled with her weight, decided to go with Weight Watchers 10 years ago.

Tucker has managed to keep off the 60 pounds (27.21 kilograms) she dropped by going to meetings and eating within the Weight Watchers points system. "It's real eating, real food. It's lifestyle," she said.

After Weight Watchers began years ago, many other diet plans have also entered the market. Those include Herbal Magic, the Canadian program that has members lose weight by taking a weekly dose of vitamins and minerals while following a meal plan.

"Basically you're taking them three times a day, they help speed up the metabolism and suppress the appetite," explained Darcie Dunnigan of Herbal Magic.

And there's Jenny Craig. That program is all about portion-control fueled by ready-made entrees delivered to members' doors every two weeks.

"It's not only a diet, it's not only about weight loss, it's about a healthy lifestyle change," said Elizabeth Frank from Jenny Craig Canada.

Each plan encourages a healthy diet and claims members will lose about two pounds a week by following the plan. That's a concern for Lindsey Mazur who is a dietician with Women's Health Clinic. She says losing weight quickly can pose serious health risks.

"Like increased cholesterol, lower blood pressure, lower bone density, lower immune systems. So it's really harmful for our health in the long run," said Mazur.

Tucker agrees not all diet plans work. In the past, she tried losing weight through pre-packaged meals. "I didn't eat regular food," she said. "I didn't eat with my family and yes I did lose weight, but I gained it back."

Tucker says she's done with dieting gimmicks and maintains her weight by making healthy food choices and exercising regularly.