The 5:2 diet, also known as The Fast Diet, is a popular intermittent fasting diet that has gained attention for its potential health benefits and weight loss capabilities. It was popularized by British journalist Michael Mosley. Intermittent fasting is an eating pattern that involves regular fasting. The 5:2 diet is an intermittent fasting regimen in which calorie intake is limited to 500-600 calories per day, two times per week. Though it may be linked to several health benefits, fasting diets may not be suitable for everyone.
This article delves into the details of the 5:2 diet, examining its principles, potential benefits, and risks, and providing guidance on how to follow it effectively.
Understanding the 5:2 Diet
The 5:2 diet is called such because five days of the week are routine 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. This approach to eating is considered more of a lifestyle change than a restrictive diet, making it easier for some individuals to adhere to in the long term.
How to Follow the 5:2 Diet: Calorie Guidelines
For five days per week, you eat normally and don’t have to think about restricting calories. On the other two days, you reduce your calorie intake to a quarter of your daily needs, which is about 500 calories per day for females and 600 for males. 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 eat too much 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.
Read also: Healthy Dinner Recipes
Potential Health Benefits of Intermittent Fasting
There are very few studies on the 5:2 diet specifically. However, recent studies on intermittent fasting in general show impressive health benefits. One important benefit is that intermittent fasting seems to be easier to follow than continuous calorie restriction, at least for some people. However, the research is conflicting, with some noting that intermittent fasting and traditional dieting have similar adherence rates. Also, many studies have shown that different types of intermittent fasting may significantly reduce insulin levels. One 2011 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.
Impact on Weight Loss
If you need to lose weight, the 5:2 diet can be effective when done right. This is mainly because the 5:2 eating pattern helps you consume fewer calories. Therefore, it is very important not to compensate for the fasting days by eating much more on the non-fasting days. Intermittent fasting does not cause more weight loss than regular calorie restriction if total calories are matched. That said, fasting protocols similar to the 5:2 diet have shown a lot of promise in weight loss studies: A 2014 review found that modified alternate-day fasting led to a weight loss of 3-8% over the course of 3-24 weeks. In the same study, participants lost 4-7% of their waist circumference, meaning that they lost a lot of belly fat. Intermittent fasting causes a much smaller reduction in muscle mass when compared to weight loss with conventional calorie restriction.
Further Research on Modified Alternate-Day Fasting
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). One 2013 randomized controlled study in both moderate-weight and overweight individuals showed major improvements in the group doing 4:3 fasting, compared to the control group that ate as usual. 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 C-reactive protein (CRP), an important marker of inflammation.
- Decreased levels of leptin by up to 40%.
Additional Potential Benefits
Fasting has the potential to optimize the levels of disease biomarkers, and lower levels of oxidative stress, as well as maintain learning and memory function. Scientists at the US-based National Institute on Aging, part of the National Institutes of Health, have looked into how intermittent fasting impacts the cardiovascular system and brain in rodents. Theories abound about how fasting yields physiological benefits. Among them is the belief that during fasting, cells experience some stress.
Moreover, a UK-based study, led by the Genesis Breast Cancer Prevention Center at University Hospital of South Manchester NHS Foundation Trust, determined that there were changes in the breast cells of some women who followed the Fast Diet, which may be indicative of protection against breast cancer. The study involved two dozen middle-aged overweight or obese women who did not have cancer nor diabetes, but whose risk for breast cancer was higher than average. The participants lost about 5% weight and body fat and experienced changes for the better in the metabolism of fat, insulin, and energy. About 50% of participants underwent biochemical changes in breast tissue, which scientists saw as possibly related to their risk for developing breast cancer. The observed changes fall short of showing that the 5:2 diet lessens the potential for breast cancer in women.
Read also: Diary of a Fat Housewife: A Review
Foods to Eat on Fasting Days
There is no rule for what or when to eat on fasting days. Some people function best by beginning the day with a small breakfast, while others find it best to start eating as late as possible. Generally, there are two meal patterns that people follow:
- Three small meals: Usually breakfast, lunch, and dinner.
- Two slightly bigger meals: Only lunch and dinner.
Since calorie intake is limited - 500 calories for women and 600 calories for men - it makes sense to use your calorie budget wisely. Try to focus on nutritious, high fiber, high protein foods that will make you feel full without consuming too many calories. Soups are a great option on fast days. Studies suggest that they may make you feel fuller than foods with the same calorie content or the same ingredients in their original form.
Here are a few examples of foods that may be suitable for fast days:
- A generous portion of vegetables
- Natural yogurt with berries
- Boiled or baked eggs
- Grilled fish or lean meat
- Cauliflower rice
- Soups (for example, miso, tomato, cauliflower, or vegetable)
- Low calorie cup soups
- Black coffee
- Tea
- Still or sparkling water
There is no specific, correct way to eat on fasting days. It is also expected to feel a little weaker or slower than usual. However, you’ll be surprised at how quickly the hunger fades, especially if you try to keep busy with work or other errands. Additionally, most people find that the fast days become easier after the first few fasts. If you are not used to fasting, it may be a good idea to keep a small snack handy during your first few fasts, just in case you feel faint or ill. But if you repeatedly find yourself feeling ill or faint during fast days, have something to eat and talk with your medical professional about whether you should continue.
Who Should Avoid the 5:2 Diet?
Although intermittent fasting is very safe for healthy, well-nourished people, it does not suit everyone. Some people should avoid dietary restrictions and fasting completely. These include:
Read also: Easy Healthy Recipes
- Individuals with a history of eating disorders.
- Individuals who often experience drops in blood sugar levels.
- Pregnant people, nursing people, teenagers, children, and individuals with type 1 diabetes.
- People who are malnourished, underweight, or have known nutrient deficiencies.
- People who are trying to conceive or have fertility issues.
Furthermore, intermittent fasting may not be as beneficial for some females as it may be for males. Some females of reproductive age have reported that their menstrual periods stopped while they were following this type of eating pattern.
Potential Risks and Considerations
There are concerns that benefits of the Fast 5:2 Diet are exaggerated, and that there may be possible risks. Fasting is popular, to the point of being a fad. Fads are dismissed by physicians and nutritionists, which might mean that patients could miss any legitimate benefits of proper fasting.