The FastDiet or 5:2 Diet: Fact or Fiction?

For two non-consecutive days a week, you limit your calories to 500 a day for women; 600 for men or the approximate equivalent of a breakfast of one egg and a cup of strawberries, an iced tea or black coffee for lunch, and four ounces boneless, skinless chicken breast with one cup steamed broccoli plus 1 cup salad greens with lemon.  Five days, almost anything goes. 

Dream weight loss regime or dietary nightmare? 

Back in 2012, the BBC aired "Eat, Fast, and Live Longer," a documentary about intermittent fasting.  In the documentary, scientist/researcher Michael Mosley explored the benefits of an extremely low calorie diet on aging or specifically, levels of blood markers such as IGF-1, an insulin-like growth hormone, glucose, and cholesterol.  In lab conditions, mice put on a calorie-restricted diet experience about a 40% greater life expectancy than their counterparts who nibble at will.  High levels of IGF-1 seem to accelerate aging and age-related conditions.  In starvation mode, the body seems to switch from growth to repair mode.

Mosley followed up the documentary with "The FastDiet," a book that topped the UK's best-seller list and has become the diet du jour across the pond. The book, co-authored with journalist Mimi Spencer, has spun off a cottage industry of feast and famine titles, including the Cliff Notes version, "The 5:2 Diet" penned by fellow Brit journalist Kate Harrison.  British women's mags, tabloids, and a slew of recipe/meal plan books feature the One from Column A, Two from Column B approach to cut calories to 500 per day. 

Cycling between starvation mode and higher calorie days is hardly a new approach.  Anyone who's fallen down the rabbit's hole of disordered eating or eating disorders is likely well-versed in how to follow up a few days of binging with compulsive dieting and exercise.  Arguably, this plan may be more proactive than reactive. 

Consistently restricting calories is ultimately ineffective on several levels.  Cutting calories below what we need impacts hormone levels and can cause the body to lose muscle mass, both of which lower our set point and metabolism.  Denying ourselves whole food groups or limiting food choices can also set us up for binging, usually on simple carbs like that donut in the office breakroom or a pizza with everything ordered at midnight.  Conversely, changing up calorie counts may be an effective way to lose and maintain weight. 

So, are calorie cycling programs like "The FastDiet" and "The 5:2 Diet" effective, safe weight loss diets? 

Most health professionals support extreme calorie deprivation only under medical supervision.  Anecdotal documentation demonstrates an average 1-2 pound per week weight loss, a safe range.  However, like any dietary program, the execution is the most powerful indicator of success.  If low calorie days of lean protein and leafy greens are followed with higher calorie days of whole foods and not cartons of Ben & Jerry's or huge plates of pasta, the program may be help you get back into your skinny jeans, if you can make it through the lean days.

Learning to eat and move intuitively is the best approach to long-lasting weight loss and maintenance.  Any diet that starts and ends on a day ending in "y" probably won't lead to lasting weight loss.

Working with a certified health coach is a useful tool to learn the skills to eat for life.  Contact me at info@bethckramer.com for a complimentary health history and consultation to get you on the right path.