The 5:2 Diet: Can You Get Beach-Ready By Fasting Twice A Week? (With 10 Low-Calorie Snack Ideas For Fasting Days)

"For those days you are restricting calories or 'fasting,' make sure you consume nutrient-rich foods to assist in receiving essential nutrients," says Dr. Joy Dubost, RD, CSSD, "including foods high in protein like lean meats, nuts, seeds, eggs, and low-fat dairy. Don't forget to include fresh fruits and vegetables, which are naturally low in calories, and a small portion of whole grains along with drinking plenty of water. The calories can quickly add up, so keeping track of intake is important."

Luckily for you, we've come up with some snack ideas and healthy, low-calorie flavor-boosters that will make any fasting day easier. If you want to try out this whole 600 calories on two out of every five days, 20 pounds in nine weeks, weight-loss lifestyle from the U.K., click ahead to see the low-calorie snacks and flavor-enhancers that we suggest for fasting days.

Nut butters are certainly not a low-calorie food, but you are probably aware that they can fill you up pretty easily. One tablespoon of almond butter has 95 calories and will spread nicely over one piece of sprouted grain toast. We checked the nutrition facts for Ezekiel 4:9 Sprouted Whole Grain Bread, and each slice has just 80 calories. Why sprouted grain toast? Simple: It contains no sugar, three grams of dietary fiber, and four grams of protein – the perfect combination for a healthy, filling snack. It even contains all nine essential amino acids, making it a complete protein source.

Black beans, like most pulses, contain impressive amounts of dietary fiber and protein (that's six grams of fiber and eight grams of protein per one-half cup). The protein and fiber in black beans alone are enough to fill you up, but we feel that there's room to add another healthy, filling food to this snack. Black beans have no fat, so introducing a small amount of avocado will increase healthy fat content (as well as up the fiber count) in your fasting day diet. Eating a whole avocado, depending on size, would probably use over half of your daily calorie allotment, so we suggest dicing up about one-fifth of a medium-sized avocado instead. This portion should have around 50 healthy, beach body-friendly calories comprised of four and one-half grams of healthy fats and three grams of carbs (two of which are from dietary fiber).

Cinnamon has a veritable library's worth of health benefits, but one of the more relevant ones to getting ready for bathing suit weather is that it's a metabolism-booster. At just under 20 calories per tablespoon, cinnamon is a tasty and low-calorie way to get some flavor on your fasting day snacks.

Egg whites are purely protein, and protein is a macronutrient that your body will need on a fasting day. Each egg's white portion accounts for 17 calories from about four grams of protein. When paired with virtually calorie-free, iron-rich spinach and healthy, low-calorie bell peppers (one medium-sized bell pepper contains about 30 calories), an egg white and vegetable omelette is as calorie-sparse and nutritious as it gets. We suggest tossing on roughly one-eighth of a cup of crumbled feta. This protein-rich cheese will help to fill you, and such a meager serving size is only 70 calories.

A four-ounce boneless, skinless chicken breast will be about 120 calories comprised of about one and one-half grams of fat and 26 grams of protein. With only 600 calories to spare, we suggest grilling up one chicken breast and splitting it into two meals. Combining two ounces of grilled chicken with some sun-dried tomatoes (110 calories per one-quarter cup) and farro (170 calories per one-quarter cup) can prove to be a filling meal. Working in one-quarter cup each of farro and sun-dried tomatoes will account for a lot of calories on fasting days, so we suggest tossing one-eighth cup of farro with three or four sun-dried tomatoes.

Many hot sauce brands contain zero calories. We grabbed a bottle of Cholula and found that it lists no calories, no fat, no carbohydrates, and no protein per serving. With that being said, feel free to drown your meals in it on fasting days if that's what you desire! It's also been shown to boost your metabolism, potentially helping with your weight-loss goals. Do be conscious of the fact that hot sauce does, in fact, contain a very miniscule, negligible amount of calories though. The amount is so small that it's not required by law to appear on the nutrition facts, so don't make yourself too crazy over it.

A one-half cup serving of old fashioned oats only has 150 calories. Oatmeal is high in fiber and protein and, when mixed with a few nuts and fresh berries, can fill you up quite well. While nuts (sorry, but we're excluding peanuts and sticking to actual nuts here) are rich in healthy monounsaturated fats, they are quite calorie-dense. For instance, a one-quarter cup serving of plain almonds has 160 calories, so use your almond calories wisely. Five or six nuts will suffice. Berries are incredibly low-calorie (a cup of fresh blueberries has just over 84 calories) and rich in antioxidants, so adding them to your oats along with almonds could be an under 250-calorie meal.

Depending on the size of the beet, the calorie range can vary from around 20 calories for smaller ones up to 35 calories for slightly larger ones. Beets have incredible nutritional benefits and they're rich in fiber, rendering them a fairly filling food. We found a great recipe that combines beets with incredibly low-calorie ingredients (green onions, ground cumin, and lemon juice) and a bit of heart-healthy coconut oil. The recipe calls for one tablespoon of coconut oil. To someone who's fasting, this means 120 calories. Consider tossing your beets and cumin with less coconut oil in order to help keep your daily calories under 600.

Click here for the Roasted Cumin Beets recipe.

Skyr, essentially the Greek yogurt of Iceland, is insanely rich in protein. One container of Siggi's plain, non-fat skyr contains 80 calories comprised of five grams of carbs and 15 grams of protein. Skyr is thicker than Greek yogurt, making it a bit more filling. Sprinkling some cinnamon on a small portion of oats and throwing them in the toaster for a little while will give them a slight crunch factor, and drizzling one tablespoon of honey (about 64 calories) on top will help cure any sweets cravings you may be having. Consider using a tablespoon of bee pollen instead of honey if you have a problem portioning out viscous liquids like we do (one tablespoon of honey usually turns to two, and sometimes two turns into three, at least for us).

Spicy brown mustard is magically calorie-free. A quick glance at its nutrition facts shows that it contains zero grams of fat, zero grams of carbs, and zero grams of protein. While there are obviously some calories in spicy brown mustard, they're negligible, making it a great addition to any low-calorie snack you're enjoying (or wishing was a bison burger) on a fasting day.