There are various methods of intermittent fasting, and people will prefer different styles. Read on to find out about six different ways to do intermittent fasting.
1. Fasting for 12 hours a day
The rules for this diet are simple. A person needs to decide on and adhere to a 12-hour fasting window every day.
According to some researchers, fasting for 12 to 14 hours can cause the body to turn its fat stores into energy, which releases ketones into the bloodstream. This should encourage weight loss.
This type of intermittent fasting plan may be a suitable option for beginners. This is because the fasting window is relatively small, much of the fasting occurs during sleep, and the person can consume the same number of calories each day.
The easiest way to follow the 12-hour fast is to include the period of sleep in the fasting window.
For example, a person could choose to fast between 7 p.m. and 7 a.m. They would need to finish their evening meal before 7 p.m. and wait until 7 a.m. to eat breakfast but would be asleep for much of the time in between.
2. Fasting for 16 hours
Fasting for 16 hours a day, leaving an 8-hour eating window, is called the 16:8 method or the Leangains diet.
Some experts may recommend females fast for 14 hours and slowly build their way up to 16 hours, while males can start fasting for 16 hours straight away.
This type of intermittent fast may be helpful for someone who has already tried the 12-hour fast but did not experience any benefits.
On this fast, people usually finish their evening meal by 8 p.m. and skip breakfast the next day, not eating again until noon.
A 2022 review found that this fasting method, alongside calorie restriction, may be beneficial for weight management in adults with overweight or obesity and may have a positive effect on blood sugar processing.
3. Fasting for 2 days a week
People following the 5:2 diet eat standard amounts of healthful food for 5 days and reduce calorie intake on the other 2 days.
During the 2 fasting days, men generally consume 600 calories and women 500 calories.
Typically, people separate their fasting days in the week. For example, they may fast on a Monday and Thursday and eat regularly on the other days. There should be at least 1 nonfasting day between fasting days.
There is limited research on the 5:2 diet, which is also known as the Fast diet.
A 2022 study examining different types of fasting found that the 5:2 diet had no clear ranking when compared with the other intermittent fasting regimens.
A 2021 randomized controlled trial found that adults with obesity who tried the 5:2 fasting method with group support experienced a greater weight loss at 6 weeks and rated the diet highly.
However, the effect of weight loss diminished over time, with the weight difference no longer being significant by 1 year.
4. Alternate day fasting
There are several variations of the alternate day fasting plan, which involves fasting every other day.
For some people, alternate day fasting means a complete avoidance of solid foods on fasting days, while other people allow up to 500 calories. On feeding days, people often choose to eat as much as they want.
Alternate day fasting is an extreme form of intermittent fasting, and it may not be suitable for beginners or those with certain medical conditions. It may also be difficult to maintain this type of fasting in the long term.
5. A weekly 24-hour fast
Fasting completely for 1 or 2 days a week, known as the Eat-Stop-Eat diet, involves eating no food for 24 hours at a time. Many people fast from breakfast to breakfast or lunch to lunch.
People following this diet plan can have water, tea, and other calorie-free drinks during the fasting period.
People should return to regular eating patterns on nonfasting days. Eating in this way reduces a person’s total calorie intake but does not limit the specific foods the individual consumes.
A 24-hour fast can be challenging and may cause fatigue, headaches, or irritability. Many people find these effects become less extreme over time as their bodies adjust to this new eating pattern.
People may benefit from trying a 12-hour or 16-hour fast before transitioning to the 24-hour fast.
6. The Warrior Diet
The Warrior Diet is a relatively extreme form of intermittent fasting.
It involves eating very little, usually just a few servings of raw fruit and vegetables, during a 20-hour fasting window, then eating one large meal at night. The eating window is usually only around 4 hours.
This form of fasting may be best for people who have tried other forms of intermittent fasting already.
Supporters of the Warrior Diet claim that humans are natural nocturnal eaters and that eating at night allows the body to gain nutrients in line with its circadian rhythms.
During the 4-hour eating phase, people should make sure they consume plenty of vegetables, proteins, and healthy fats. They should also include some carbohydrates.
Although it is possible to eat some foods during the fasting period, it can be challenging to stick to strict guidelines on when and what to eat in the long term. Some people may also have difficulty eating such a large meal so close to bedtime.
There is also a risk that people on this diet will not eat enough nutrients, such as fiber. This can increase the risk of cancer and have an adverse effect on digestive and immune health.
