The 5:2 diet is one of the most flexible eating plans on the planet, requiring dieters to cut calories just two days out of the week. It also doesn’t come with a long list of rules or regulations, making it a great choice for those looking for a bit of wiggle room with their diet.
In addition to being simple and easy to follow, this popular plan has also been linked to a number of health benefits, ranging from better blood sugar control to decreased inflammation.
So what is the 5:2 diet, and is it worth a try? Here’s everything you need to know about this popular eating plan, including how to follow it, how it works and how it can impact your health.
What Is the 5:2 Diet?
The 5:2 diet is a popular eating pattern that involves intermittent fasting two times per week. It was initially developed by Michael Mosley, a British broadcaster and physician who published the 5:2 diet book, “The Fast Diet,” in 2013.
By following the 5:2 diet, Mosley says that he was able to shed extra body weight, reverse his diabetes and improve his overall health.
The 5:2 diet plan is very simple. Rather than setting strict guidelines on which foods are permitted, it involves making changes to when you eat and how much.
For five days out of the week, you are able to follow a normal diet without tracking calories or macronutrients. Meanwhile, on two non-consecutive days per week, the plan requires you to restrict your intake by about 75 percent, which is typically around 500–600 calories.
Like other fasting diets, such as time-restricted eating, there are no rules about which foods you should or shouldn’t eat during your fasting and non-fasting days. However, it’s recommended to limit processed foods and consume a variety of nutrient-dense, whole foods to maximize the potential benefits.
Although there is very little research on the 5:2 diet specifically, other similar eating patterns have been linked to a long list of health benefits. Here are a few of the potential benefits of this popular eating plan.
1. Promotes Weight Loss
One of the main reasons that people start the 5:2 diet is weight loss. Because it involves cutting back on calories twice per week, it can reduce your overall caloric intake, which can lead to increased weight loss.
In fact, according to one study in International Journal of Obesity, the 5:2 diet could be as effective for weight loss as traditional low-calorie diets. Similarly, other studies have found that intermittent fasting could help reduce both body weight and belly fat to improve overall body composition.
Keep in mind that what you eat is very important and can affect the potential results of the diet. Be sure to load your plate with a variety of healthy, nutrient-rich foods, even on days when you’re not fasting, to boost the potential 5:2 diet results.
2. Reduces Inflammation
Inflammation is a normal immune process that is absolutely essential to overall health. However, sustaining high levels of inflammation over time can contribute to chronic disease, including conditions like heart disease, cancer and diabetes.
Plus, it may also worsen symptoms of autoimmune disorders, including rheumatoid arthritis and inflammatory bowel disease.
Dietary patterns that involve intermittent fasting have been shown to help decrease levels of inflammation in the body. One study conducted in Florida, for example, found that alternate-day fasting was able to reduce levels of oxidative stress after just three weeks.
Another study reported that intermittent fasting effectively suppressed the production of pro-inflammatory immune cells, leading to decreased inflammation in the body.
3. Supports Heart Health
Heart health is a major concern for millions of people around the globe. Not only is heart disease the leading cause of death worldwide, but health expenditures related to heart disease and stroke cost an average of $316 billion per year in the United States alone.
Studies show that fasting can improve several markers of heart health, which could help protect against disease. In one study, fasting was shown to reduce cholesterol, triglycerides and blood pressure, all of which are risk factors for heart disease.
Plus, another animal model found that alternate-day fasting reduced the risk of heart attack in rats by 66 percent.
4. Improves Blood Sugar Control
Studies show that intermittent fasting can improve blood sugar control to promote long-term health in those with and without type 2 diabetes. For instance, one pilot study found that intermittent fasting for two weeks was able to decrease body weight and reduce blood sugar levels in 10 people with diabetes.
What’s more, another study out of Malaysia demonstrated that fasting could also improve insulin sensitivity, which can lead to better blood sugar control over time.
Despite these promising results, more research is needed on the effects of the 5:2 diet specifically. Additionally, if you have type 2 diabetes or are taking any medications for blood sugar, it’s best to consult with your doctor before switching up your diet.
5. Simple and Sustainable
Compared to other diet plans, such as the Warrior Diet, the 5:2 diet is very simple, flexible and easy to follow. You can select your fast days based on your schedule, pick which foods you eat and tailor the diet to fit your lifestyle.
Additionally, the 5:2 diet only requires you to restrict your food intake two days per week, unlike other low-calorie diets that involve eating smaller portions and tracking your intake all week long.
For this reason, the 5:2 diet may be more sustainable than other plans in the long run. It may also be a good option for those looking to shed extra pounds as well as those simply looking to maintain weight loss long term.
How It Works
The 5:2 diet is a form of intermittent fasting, which is a diet pattern that involves cycling between periods of eating and restricting or abstaining from food.
Intermittent fasting has been shown to alter levels of specific hormones in the body, many of which can be beneficial to health. For example, it may help lower levels of insulin, which is the hormone that is responsible for shuttling sugar from the bloodstream to the cells.
Reducing levels of circulating insulin can improve insulin sensitivity, which can enhance your body’s ability to use this important hormone efficiently.
Because the diet involves reducing your caloric intake two days per week, it can also help support weight loss by decreasing the total number of calories that you consume.
The diet is very simple and easy to follow because it only requires you to switch up your diet two days per week. On these two days, you should limit your calorie consumption to about one-fourth of your usual intake.
For men, it’s recommended to stick to around 600 calories while women should aim for approximately 500 calories.
Although there are several 5:2 diet apps available online, you can use any calorie counter to keep tabs on your intake. Alternatively, try calculating it by hand by reading food labels and keeping a written journal.
How to Eat on Fasting Days
Because there are no rules or regulations about which foods to eat and avoid, a typical 5:2 diet meal plan can vary quite a bit depending on your personal tastes and preferences.
However, as a general rule of thumb, you should stick to nutritious foods that are low in calories when building your intermittent fasting meal plan. Some of the best foods to enjoy on your fasting days include:
- Fruits: apples, pears, bananas, oranges, blueberries, melons, strawberries, kiwi
- Vegetables: broccoli, cauliflower, kale, spinach, arugula, zucchini, radishes, carrots, tomatoes
- Proteins Foods lean cuts of beef, skinless poultry, white fish, tempeh, beans, lentils, eggs
- Whole Grains: oats, quinoa, couscous, brown rice, popcorn, barley
- Dairy Products: milk, yogurt, cottage cheese
- Herbs and Spices: turmeric, black pepper, cumin, rosemary, oregano, basil
- Beverages: water, unsweetened tea, black coffee, bone broth
Meanwhile, high-calorie foods that are highly processed or refined should be restricted as part of the diet. Here are some foods to avoid on your fasting days:
- Refined Grains: white rice, tortillas, pasta, white bread, crackers
- Added Sugars: table sugar, honey, syrup, soda, sweet tea, fruit juice, baked goods, cookies
- Processed Foods: convenience meals, fast food, microwave popcorn, potato chips, processed meats
- Unhealthy Fats: fried foods, refined vegetable oils, shortening, lard
Here is a sample one-day meal plan for a 500-calorie diet:
- Breakfast: 1/2 cup oatmeal with cinnamon and 1/2 cup blueberries
- Lunch: 4 ounces grilled chicken with 1/2 cup steamed asparagus
- Dinner: 4 ounces baked codfish with 1 cup roasted broccoli
- Snacks: celery with 2 tablespoons hummus
How to Eat on Other Days
On two days out of the week, you should restrict your intake to just 500–600 calories per day. However, on the remaining five days, you can follow a normal diet without counting calories (such as in the CICO diet).
Although there are no specific guidelines for which foods to eat during the week on the 5:2 diet, it’s best to fill your plate with healthy ingredients like fruits, veggies, proteins, whole grains, nuts, seeds and healthy fats. Conversely, processed ingredients like sugar-sweetened beverages, frozen meals and junk foods should be limited.
Here are a few delicious 5:2 diet recipes to help get you started:
- Greek Chicken Souvlaki
- Crockpot Collard Greens
- Beef and Quinoa Stuffed Bell Peppers
- Summer Sautéed Veggies
- Hearty Spaghetti Squash Casserole
Risks and Side Effects
For most healthy adults, the 5:2 diet can be a safe and effective way to improve several aspects of health. Unlike other forms of intermittent fasting, such as intermittent fasting on keto, which often involve completing a 24-hour fast or limiting foods and drinks to an eight-hour diet window, the 5:2 diet requires you to cut calories just two days per week, which may make it easier to follow and more manageable.
That said, the diet is not recommended for children, teenagers, those with a history of disordered eating, or women who are pregnant or breastfeeding. Those who have diabetes or take medications to lower blood sugar levels should also consult with a trusted health care professional before making any dietary changes.
If you have any other underlying health issues, you may also want to talk to your doctor to avoid any adverse effects on health.
Studies also show that fasting may alter hormone levels and could potentially impact women differently than men. Fortunately, fasting just a few days per week and scheduling your fasting periods for non-consecutive days during the week can help reduce the risk of adverse side effects associated with intermittent fasting for women.
Keep in mind that cutting calories can cause side effects like headaches, irritability, weakness and fatigue. Although these side effects usually resolve over time, you may want to talk to your doctor about whether or not to continue the diet if symptoms persist.
- What is the 5:2 diet? Originally based on a book by Michael Mosley, this popular fasting diet plan involves reducing caloric intake two days per week and following a regular diet on the remaining five days.
- Although research on the 5:2 diet specifically is limited, some studies suggest that it could help increase weight loss, improve heart health, reduce inflammation and enhance blood sugar control.
- However, it’s important to fill your plate with a variety of nutrient-dense foods to maximize the potential 5:2 diet results.
- The 5:2 diet is not recommended for children, teenagers, those with a history of disordered eating, or women who are pregnant or breastfeeding.
- Additionally, if you have any underlying health conditions, you may want to consult with a health care professional before making any changes to your diet.