By Stephanie Stahl

PHILADELPHIA (CBS) — How to have a guilt-free Thanksgiving feast.  Eat your favorite foods and don’t worry about gaining weight.  3 On Your Side Health Reporter Stephanie Stahl reveals how you can enjoy a big dinner anytime.

Go ahead and dig in.  Have a Thanksgiving feast.

Yes, believe it or not, some say you can have your pumpkin pie and eat it too with a growing diet trend.

“You can have what you want.  I lost about two-and-a-half inches just about everywhere,” said Randi Graves, who is back on the Fast-5 Diet.  It’s a diet where she can eat cookies and bread.

“For the holidays I’m definitely going to indulge in stuffing,” said Randi.  The plus size model is able to indulge and still maintain her figure by controlling not what she eats, but when.  For five consecutive hours she can eat anything, then she has to fast for 19 hours.

“I just stopped all foods after 8pm, and I had no foods until 3pm.  I never found myself overeating because your stomach is shrinking, and that’s what I think triggers weight loss,” said Randi.

The Fast-5 Diet is among several that advocate intermittent fasting.  Among them the popular 5-2 Diet where people eat anything for five days, and fast or limit calories to 500 daily for two days.

“It’s almost a personal self-cleanse, a quick cleanse,” said Martin Rittenbery, on the Fast-5 Diet.

“This is about correcting appetite,” said Dr. Bert Herring, who developed the Fast-5 Diet.  He says periodic fasting reduces the size of the stomach.  People end up eating fewer calories and the brain is retrained.

“The appetite center gets to be much stronger, and the signal to stop eating when it’s time gets to be stronger,” said Dr. Herring.

Regular exercise has helped Randi stay in shape.  She admits fasting is hard at first, but being able to enjoy anything she wants is a motivating reward.

It’s working for Randi, but it’s not for everyone.  Experts say fasting can cause problems for some people who are on mediation or have blood sugar issues.  Be sure to always check with your doctor.

The Fast-5 Diet-

The 5:2 Diet-