Intermittent fasting is an eating pattern that involves regular fasting.The 5:2 diet, also known as The Fast Diet, is currently the most popular intermittent fasting diet.It was popularized by British journalist Michael Mosley.It’s called the 5:2 diet because five days of the week are normal eating days, while the other two restrict calories to 500–600 per day.
Because there are no requirements about which foods to eat but rather when you should eat them, this diet is more of a lifestyle.
Many people find this way of eating to be easier to stick to than a traditional calorie-restricted diet (1).
This article explains everything you need to know about the 5:2 diet.
The 5:2 diet is actually very simple to explain.
For five days per week, you eat normally and don’t have to think about restricting calories.
Then, on the other two days, you reduce your calorie intake to a quarter of your daily needs. This is about 500 calories per day for women, and 600 for men.
You can choose whichever two days of the week you prefer, as long as there is at least one non-fasting day in between them.
One common way of planning the week is to fast on Mondays and Thursdays, with two or three small meals, then eat normally for the rest of the week.
It’s important to emphasize that eating “normally” does not mean you can eat anything. If you binge on junk food, then you probably won’t lose any weight, and you may even gain weight.
You should eat the same amount of food as if you hadn’t been fasting at all.
SUMMARYThe 5:2 diet involves eating normally for five days per week, then restricting your calorie intake to 500–600 calories on the other two days.
Health Benefits of Intermittent Fasting
There are very few studies on the 5:2 diet specifically.
However, there are plenty of studies on intermittent fasting in general, which show impressive health benefits (2, 3).
One important benefit is that intermittent fasting seems to be easier to follow than continuous calorie restriction, at least for some people (4, 5).
Also, many studies have shown that different types of intermittent fasting may significantly reduce insulin levels (2, 6, 7).
One study showed that the 5:2 diet caused weight loss similar to regular calorie restriction. Additionally, the diet was very effective at reducing insulin levels and improving insulin sensitivity (8).
Several studies have looked into the health effects of modified alternate-day fasting, which is very similar to the 5:2 diet (ultimately, it’s a 4:3 diet) (9).
The 4:3 diet may help reduce insulin resistance, asthma, seasonal allergies, heart arrhythmias, menopausal hot flashes and more (10, 11).
One randomized controlled study in both normal-weight and overweight individuals showed major improvements in the group doing 4:3 fasting, compared to the control group that ate normally (12).
After 12 weeks, the fasting group had:
- Reduced body weight by more than 11 pounds (5 kg).
- Reduced fat mass by 7.7 pounds (3.5 kg), with no change in muscle mass.
- Reduced blood levels of triglycerides by 20%.
- Increased LDL particle size, which is a good thing.
- Reduced levels of CRP, an important marker of inflammation.
- Decreased levels of leptin by up to 40%.
SUMMARYThe 5:2 diet may have several impressive health benefits, including weight loss, reduced insulin resistance and decreased inflammation. It may also improve blood lipids.