The Beginner's Guide to the 5:2 Diet

If you’re interested in losing weight, you might consider the 5:2 diet. When you practice 5:2 intermittent fasting, you limit calories on two non-consecutive days each week. 

It’s not the easiest diet. You’ll be hungry on fasting days, especially if you walk by a Cinnabon without a clothespin on your nose. 

But some research suggests that 5:2 trumps continuous caloric restriction for curbing hunger on the way to a slimmer figure.[*] Fewer hunger pangs, happier you. 

Read on to learn the basics of the 5:2 diet, how to structure fasting and feeding days, a sample 5:2 diet plan, published benefits, risks, and tips for implementing a fasting schedule. First, though, let’s review the big picture. 

Introducing Intermittent Fasting

Our cave-dwelling ancestors practiced intermittent fasting (IF) as a matter of course. Hunting and gathering didn’t always work out, so they often had to pause their calorie consumption. 

That’s a good definition of IF: taking regular breaks from calories. 

When you take these breaks, your body gets the memo. Energy is scarce, says the memo—time to start burning body fat.

Burning fat gives you energy to find more food. That energy is valuable whether you’re hunting antelope or developing a business strategy. 

But when you eat all the time, you send the opposite memo. Energy is abundant—let’s store fat for later. 

Welcome to the modern obesity crisis, brought to you by hyper-palatable foods. 

Intermittent fasting schedules like 12/12, 16/8, OMAD, ADF, and 5:2 help us curb overeating and reactivate fat-burning mode. Let’s dive into 5:2 now. 

What Is The 5:2 Diet?

The 5:2 diet involves consuming 0–25% of your usual calories on two non-consecutive days each week. The other five days, you eat normally. 

So if your maintenance diet is 2000 calories daily, you’d consume 500 calories on fasting days. We’ll presume 500-calorie fasting days for the remainder of the article, but be sure to adjust for your own needs. 

If you do 5:2 by the book, you’re almost guaranteed to lose weight. That results from consuming fewer calories (week after week) than your metabolism requires. 

How To Eat on 5:2

Eating a 5:2 diet means cleaving your week into fasting and feeding days. 

Fasting Days

On fasting days, split your 500 calories into two or three meals. These meals should consist of whole foods that deliver maximum nutrition for minimal calories. 

Protein and veggies, people. Protein and veggies. 

Protein sources like meat, fish, and eggs will help you maintain muscle as your body cries out for energy. And vegetables provide vitamins, minerals, and polyphenols without adding significant calories. 

Feeding Days

You should also structure feeding days mindfully. Since your true feeding window is limited to five days, you have fewer chances to consume essential nutrients. 

Make those chances count. Maximize your macronutrient and micronutrient intake to keep your body humming along. 

Unless you’re doing a low-carb or Keto diet, don’t overthink macros. Just aim to consume at least 1.2 grams of protein per kilogram of body weight to prevent muscle loss.[*] (About 98 grams daily protein for a 180-pound person.)

Meanwhile, whole foods like meat, fish, veggies, fruits, and nuts will supply crucial micronutrients. Confirm you’re on track by logging your meals with Carb Manager.

Sample 5:2 Diet Plan

Below are sample fasting and feeding days on the 5:2 diet. 

Fasting Day (~500 calories)

Breakfast: Keto 5:2 Mushroom and Spinach Omelet

Lunch: Keto 5:2 Simple Chicken Salad

Dinner: Keto 5:2 Ground Beef and Cauliflower Dinner

Feeding Day (~2000 calories)

Breakfast: Low-carb egg and spinach cheese cup (307 calories)

Lunch: Chicken and avocado salad (564 calories)

Snack: Cheese, bacon, and walnut fat bomb (132 calories)

Dinner: Bacon-wrapped chicken thighs with cheddar sauce (676 calories)

Dessert: Low-carb chocolate chip mug cookie (325 calories)

Benefits of 5:2 Intermittent Fasting

The potential benefits of 5:2 fasting mirror the benefits of caloric restriction.[*][*][*] In obese and overweight people in particular, you may see metabolic benefits including:

• Weight loss
• Reduced total and LDL cholesterol
• Reduced triglycerides
• Reduced blood pressure
• Lower blood sugar

One study showed that 5:2 fasting improved a range of markers (body weight, inflammation, triglycerides, and markers of liver damage) in people with non-alcoholic fatty liver disease.[*] Another found 5:2 to lower blood sugar more (with less self-reported hunger) than continuous calorie restriction in normal-weight people.[*] 

Risks and Who Should Avoid

Anyone without weight to lose should avoid the 5:2 diet. It’s best suited for reducing excess body fat.  

Even if you have excess fat, you should be wary of muscle loss. Restricting calories means restricting amino acids, the building blocks of lean mass.

Older folks should be especially cautious with fasting. Age-related muscle loss (sarcopenia) is the cause of many falls, injuries, and functional declines.[*]

Because fasting restricts essential nutrients, the following groups should avoid fasting entirely:

• Growing children
• Pregnant and nursing women
• Underweight people
• People with a history of eating disorders

Many other factors—medications, health conditions, etc.—could make 5:2 unwise for you. Talk to your healthcare professional if you’re not sure.

Tips for Trying the 5:2 Diet

Still keen on 5:2 fasting? Here are some rapid-fire tips to keep you on track:

• Know thy goals. If your goal is anything other than weight loss (performance, muscle gain, maintenance, etc.), 5:2 isn’t the proper diet for you. 
• Work up to it. If you’ve never fasted, don’t start with 5:2. Start with an overnight fast and gradually extend your food breaks as your body adapts. 
• Prioritize protein. Make your meals revolve around protein to preserve your beautiful muscles. 
• Strength train. Muscles need resistance too. You'll lose them if you don't use them. 
• Deal wisely with hunger. Hunger ebbs and flows. Stay busy during fasting days and sip non-caloric beverages to keep your mouth occupied.
• Take electrolytes. Fasting depletes electrolytes, especially sodium.[*] Replace these crucial minerals to avoid headaches, cramps, fatigue, and other symptoms. 
• Track your nutrition. Ensure you hit calorie, protein, and micronutrient targets by logging your meals with Carb Manager. While you’re there, use the IF tracker to motivate your preferred schedule. 

One last tip is to measure success holistically. Track your weight—yes—but don’t neglect more subjective measures like energy, sleep, stress, and mood. 

If these measures aren’t improving, maybe 5:2 is too aggressive for your body. You want sustainable improvement in all areas of health, not an unsustainable improvement in one.