Exercising six days a week is one way 28-year-old Kristi Norton is trying to lose weight.
"I feel like I want to get healthy and I want to be the person that I feel like I am inside."
Kristi is also learning to make healthy food choices. And she used to be a diet soda drinker.
"In the can I prefer diet Pepsi but in the bottle I prefer diet Coke."
But now she's strictly water.
"I'm in the water only group."
Kristi is taking part in research underway at the Cu Anschutz Health and Wellness Center in Aurora, Colorado.
Participants sign up for the Colorado Weigh Program - three months of weight loss and nine months of weight maintenance.
But they're also sorted into two groups - half drink zero calorie beverages - the other half just water.
"This is the first trial that compares water directly with non nutritive beverages for a long period of time in people who are doing the torture test lose weight and keep it off," says Dr. John Peters.
The hypothesis is that the results should be the same because both are calorie free.
But no one knows for sure.
So the bottom line is is that diet Coke everyday going to help you lose weight or hinder?
Half the study participants must make a commitment to go cold turkey.
"I'll hear the swish/swish and I'm like 'who has it? What is it? I want that' but it passes it's ok."
Kristi is more than willing to lose her diet drinks if it means gaining a healthier lifestyle.