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

More often than not, the offseason work we should be putting into maintaining our physique goes out the window. "It's winter," is an all-too-easy excuse for an extra scoop of ice cream here and adding one more handful of peanuts to your lunch than usual there. As the winter weight starts increasing, the days until our next bathing suit-involving vacation decrease and, eventually, we look to unhealthy crash or fad diets with the hope of becoming beach-ready in just two weeks. Sorry folks, but this is rarely (if ever) a successful approach.

Click here for 10 Filling Low-Calorie Snack Ideas.

What is successful, however, is leading a healthy eating lifestyle. While diets may fail, living in a way that incorporates healthy eating practices into one's daily life is the key to being truly happy with one's weight. One of the trendiest ways of doing this is an eating method called intermittent fasting.

We reached out to a nutrition expert, Dr. Joy Dubost, RD, CSSD, to learn a little more about what this way of eating entails.

"Although there are various versions of this," says Dr. Dubost, "the most popular is the 5:2 intermittent fasting diet. For five days you eat with no restrictions, [and on] the other two you limit your intake to less than 600 calories per day or about 25 percent of your normal caloric needs."

Some versions of the diet limit women to an unbelievably low 500 calories, allowing only men to consume 600. The diet originated in the U.K. and quickly spread to other areas of Europe before invading the United States. Why did it spread so quickly? People were thrilled with the results.

"Proponents of this way of eating claim it not only will lead to weight-loss, but could reduce your risk of chronic disease by lowering bad cholesterol, improving insulin sensitivity, and reducing inflammation in the body," says Dr. Dubost. Other than potential improvements in health, it's important to note the expected weight-loss after embarking on five days of eating and two days of fasting: People lose an average of 20 pounds after the first nine weeks.

It sounds too good to be true, so we suggest trying out intermittent fasting on a smaller scale before diving in to a 5:2 type of eating. Trying it as a "diet" before setting it as your normalized way of eating may prove a beneficial experiment or trial phase. One way of doing this is to try eating in an eight-hour window during the day, and fasting for the other 16 hours. You can assess how your body reacts to this and progress from there.

Other people practice an every-other-day type of fasting. Some take it to the extreme, consuming nothing but water every other day. No food every other day sounds awfully close to an unsafe crash diet to us, and there are some reasons dietary experts are hesitant to give even the 5:2 method their seal of approval.

"Critics of this diet have laid out a few reasons to proceed with caution, including the diet slowing down the metabolism and overeating on five of the seven days due to the two-day restriction," says Dr. Dubost. However, she points out that studies have not shown any decrease in metabolic rate, and that people pursuing this course of action generally do not overeat on their "on" days.

She urges those considering such a diet to tackle it with informed caution, however:

"If you choose to try this approach, consulting with a physician or registered dietitian would be advised. To date, research does not indicate this diet is physically harmful for healthy adults, although you may feel tired and lethargic on fasting days. This approach is not advised for those with health conditions, those taking certain medications, or women who are pregnant. Intermittent fasting may be a promising approach to lose weight and improve other health parameters, but we are unclear whether this approach provides long-term benefits. Remember, it's not what you do any given day, but what you do over time that counts."

As you're approaching the deadline (you could probably use that whole 20 pounds in nine weeks thing as a timeline) for becoming beach ready, what does all of this mean to you? Dr. Dubost notes that this method of eating takes a lot of the guesswork out of dieting. The only work you have to do is figuring out how to stay sane during fasting days or periods.

"For those days you are restricting calories or 'fasting,' make sure you consume nutrient-rich foods to assist in receiving essential nutrients," says Dr. Dubost, "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.

Dr. Joy Dubost, RD, CSSD, is a registered dietitian, food scientist, speaker, and media spokesperson. Dubost is the owner of Dubost Food & Nutrition Solutions, LLC based in Washington DC. Her nutrition advice has been featured in WebMD, Prevention, USA Today, NY Times, and the Washington Post as well as on national television and radio including CBS News, ABC News, Fox News, and NPR news. Follow her on Twitter at @joyofnutrition or visit her website