Intermittent Fasting has become a popular way to lose weight by paying attention to when you eat instead of what you eat.
Sofia Cienfuegos said she first turned to the diet last year as she was getting ready for her wedding.
"What I do is I fast until 3 p.m. and then I start eating at three and then stop at 7 p.m. and then start fasting again until next day,” Cienfuegos explained.
Merely eating during a four-hour window over three months helped Cienfuegos lose 10 pounds by her wedding day.
"I got to the weight that I wanted but I do it also because I feel way better when I’m fasting,” she said.
Cienfuegos, a dietician, is now working with Dr. Krista Varady, a professor of nutrition at the University of Illinois Chicago who has been studying nutrition for the past 20 years.
One study Dr. Varady conducted in Chicago found intermittent fasting works for weight loss.
"People lost about 7 pounds over three months and we also saw nice decreases in blood pressure, so it basically could contribute to heart health in general,” she said.
Those dieters followed time-restricted eating, one of the two main types of fasting.
They fasted for 16 hours and only ate during an eight-hour window.
Varady also wrote a book about the other type called ‘Alternate Day Fasting,’ which is when you eat whatever you want one day, but then limit yourself to 500 calories the next.
"With alternate day fasting you get to get a day off dieting every other day,” Varady said.
Jennifer Bruning, spokesperson for the Academy of Nutrition and Dietetics says there’s concern fasting leads to feasting.
"I cannot wholeheartedly recommend it,” Bruning said. “It can be one of the pitfalls of the diet actually, that if we get so hungry that in our next time period of eating we are indulging in very rich or fatty foods.”
Varady though, says that dozens of studies have actually shown that people don't binge with alternate day fasting.
"It’s good for people who aren’t frequent snackers," she said.
Although the Academy of Nutrition and Dietetics does not recommend intermittent fasting, they advise anyone who wants to try it to focus on fruits and veggies and lean proteins, to be careful not to binge and to also take a multi-vitamin to make sure you're getting the nutrients your body needs.
In addition, those wondering about that eating window, experts say you have the flexibility to shift that window.