5 Types of Intermittent Fasting (and the 1 a Dietitian Recommends)

You've tried eating healthy, tracking your macros, monitoring your portions, and exercising like crazy, but your body isn't where you want it to be. Enter: intermittent fasting.

Although there are a variety of methods of intermittent fasting, most involve eating for a certain period of time and then not eating for a certain period of time. Certified dietitian Leslie Langevin, MS, RD, CD, of Whole Health Nutrition says that aside from a number of health benefits including lowering diabetes and other disease risks, improving blood sugar levels, extending life spans, and improving memory, intermittent fasting could be another tool in your belt to help with weight loss or to break through a weight-loss plateau.

She says, "It gets your body out of 'storage mode' and mobilises fat stores for energy." This means that without having the constant source of food (fuel) you'd get from eating all day, your body will dip into the fat it already has stored. That's why people find so much success losing weight with intermittent fasting. There are a few different methods described below so see which one might be right for you.

16/8 or Leangains

What is It? Made popular by fitness expert Martin Berkhan, this method involves a 16-hour fasting window and an eight-hour feasting window. An example would be to stop eating at 7:00 p.m. and then fast until 11:00 a.m. the next day. During the feeding window, two to three meals are consumed, consisting of healthy, whole foods. There are specific guidelines about what to eat, but on all days, protein is pretty high.

Pros: All you do is skip breakfast and have lunch as your first meal. If your mornings are busy, this time tends to fly by.

Cons: It's tough if you're one of those people who needs to eat in the morning in order to function or if you do early morning workouts. You can change the fasting window so you stop eating at 6:00 p.m. and start eating again at 10 a.m. the next day. The specific eating guidelines could be a turnoff.

5:2 or Fast Diet

What is It? Made popular by British journalist and doctor Michael Mosley, twice a week (nonconsecutive days) you restrict calories to around 500 calories a day (600 calories for men), and for the other five days you eat as if you are not on a diet. You can eat three small meals or two slightly larger meals (lunch and dinner).

Pros: This plan is flexible, with no restrictions on what you can eat on regular days, and you can choose which days to fast based on your schedule. Some may welcome only having to restrict and monitor their diet twice a week.

Cons: Not eating a ton for a whole day can be really tough, especially if you work, exercise, or have a family (preparing food for your kids is way too tempting!). Also, insane hunger the day after a fasting day can cause you to overeat, which won't help you lose weight.

Eat, Stop, Eat

What is It? Created by Brad Pilon, this method involves fasting for 24 hours once or twice a week.

Pros: You only restrict your calorie intake once or twice a week, then eat however you want the rest of the time — no foods are off limits. The time frame is flexible — you can stop eating at 6:00 p.m. and then can start eating at 6:00 p.m. the following day, so you don't have to go for an entire day without food.

Cons: Not eating for a full 24 hours is tough for most people and may increase the likelihood of binging once the fast is over. Also, only restricting your calories once or twice a week may not result in the weight loss you're after.

The Warrior Diet

What is It? Designed by Ori Hofmekler, you fast for 20 hours each day then eat one large meal every night.

Pros: Raw fruit and veg, fresh juice, and a few servings of protein, if desired, are allowed during the fasting window.

Cons: The strict guidelines about what to eat for that final meal can be hard to follow, and some don't like eating a large meal at night.

Alternate Day Fasting or UpDayDown Day Diet

What is It? Started by James Johnson, MD, you eat very little one day (one-fifth your normal daily calorie intake), then the next day eat your normal daily calorie intake. Then repeat! For example, on fasting days, you eat 400 calories, and on nonfasting days, you eat 2,000 calories.

Pros: Cutting this many calories per week results in weight loss.

Cons: You may find it too strict for your schedule to fast every other day. Or you might find it hard to stick to 500 calories on those fasting days, which can also increase the likelihood of going overboard on calories on your regular eating days.

One thing Leslie warns about when thinking about intermittent fasting is that if you have a history of eating disorders, it could trigger unhealthy behaviours. And although you're restricting calories at certain points, intermittent fasting doesn't give you the green light to eat bad things like fries and ice cream during your eating window. The quality of the calories you do consume is still very important. Leslie also comments that you can't increase your daily calorie amount and expect to lose weight.

Leslie wouldn't recommend the plans that restrict daily calories to 500 a day or not eating all day, unless it's for religious reasons. For women, this can stress out the body, affecting normal hormone production, and if calories are restricted too much, it can stop a woman's menstrual cycle. She says, "The 16/8 intermittent fasting plan is a safer version and can still have the boost of weight loss success you need." It's also a plan you can safely commit to on a long-term basis.