But there's one diet that's telling people less of what they can't have and more about when they can eat.
When you hear the word fasting, you may associate it with starving.
But through intermittent fasting, you don't starve all day, and you may say goodbye to a slowed down metabolism.
"You just have a window that you eat, and I think the easiest to start off with is 8 hours," Eric Fredinburg said.
Fredinburg has been intermittent fasting for about 2 years, meaning he only eats his meals in certain time windows throughout the day.
Now about 25 pounds lighter, he says he's happy with his results.
"I've now got it to the point where I try to make it to 1 o'clock without eating and then I eat between 1 and 6, but that took awhile to get to that point," Fredinburg said.
Common plans include the 16/8 method, where you fast for 16 and are allowed to eat during 8.
Dietitians say you're able to eat whatever you want during your eating hours, but recommend a healthier meal for better results.
"Instead of feeling like you're restricting your calories every single day they could feel a little more like they can stick to it because they're able to eat more regularly for those other times," Registered dietitian Lizzie Kasparek said.
Kasparek says studies show that people lose more fat over muscle, and your metabolism won't have a slowed effect as long as you follow the plan correctly.
"If this is something that somebody wants to try and they don't feel like they're restricting their food options, of course as a dietitian I am telling people that you can probably meet your goals and not necessarily focus on weight," Kasparek said.
Kasparek says before embarking on a meal plan like this it's a good idea to check with your doctor.
"It does work for a lot of people and at the end of the day you have to find what works for you," Kasparek said.
Fredinburg says by tweaking rules here and there, this meal plan is the one for him forever.
"You just have to play around with it, see what's best for you," Fridenburg said.
For more information on intermittent fasting, click here.
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Wellness & Nutrition
There are many diets out there that tell you what you can and can't eat in order to get the results you want.