Stacey Frattinger, RD, CHFS, Certified Integrative Health Coach, currently resides in Sparks, NV. She owns a virtual health coaching and nutrition counseling practice, mainly focusing on one-on-one, individualized whole body wellness practices.
In the simplest terms, the Fast Diet is based upon a 5:2 eating plan, which equates to 5 days of “normal” eating and 2 days of a 500 – 600 calorie diet. You choose the 2 days you wish to fast each week, and on the other 5 days, you are free to eat whatever you desire, without watching calories or portion sizes. However, the authors suggest choosing high-protein foods, such as poultry, meat, nuts, seeds and legumes to help curb hunger throughout the week. In addition, on your fast days, it is recommended that you focus on eating low-glycemic fruits and vegetables along with your choice of protein to help balance your blood sugar and insulin levels. According to the teachings of Mosely and Spencer, through the process of intermittent fasting, we begin to fool our bodies into thinking that a famine is occurring, causing the body to switch from maintenance mode into fat burning. As the body responds to this naturally induced stressor, it becomes more resilient and is better able to fight off infections and disease states. If you decide to buy the book, you will be guided through 10 sample fasting days, and have access to glycemic index charts.
The Fast Diet is based upon the book written by Dr. Michael Mosley and Mimi Spencer. Mosley and Spencer joined together to write the book “The Fast Diet” after Mosley personally experienced significant health improvements with a fasting regime. Mosley was able to lose 20 pounds after he embarked on journey to better health in 2012 using this approach. Because Mosely was able to lose weight and improve his health using a modified-fasting approach, he went on to write the book with Spencer to promote his approach to weight loss and wellness. Mosely trained to be a doctor at the Royal Free Hospital in London before joining BBC as a science journalist and executive producer. The diet became very well publicized in the US after Mosely published his documentary detailing his weight loss and experience with fasting, which highlighted a series of lab tests and medical exams to demonstrate his improvements.
Compliance is going to vary depending with your fasting versus non-fasting days. During your non-fasting days, you won’t have to follow any rigid rules or restrictions. On your fasting days, however, compliance may be a very big issue. Most will find the 500-600 calorie days to be quite restrictive, and after a while, your hunger may get the best of you, causing severe cravings which then lead to going over your calorie budget. If you can make it through 2 fasting days each week, the rest of the week will probably feel easy and natural.
Given that 2 days a week are full of lean proteins along with low-glycemic fruits and vegetables, but in very small quantities, you probably won’t notice a change in your grocery bill. You might actually save a little money because your food intake will be so limited during your fasting days.
The amount of time you wish to devote to this plan is up to you! If you want to get fancy with your meals on your non-fasting days to really savor and enjoy all of your meals, you certainly can. During fasting days, it may be helpful to use protein shakes or ready-to-eat meal replacements to help stay within the calorie guidelines. These supplements will act as a both a time-saver and a way to avoid having to weigh and measure out portions to stay within the calorie guidelines.
There’s little research that specifically shows how safe the Fast Diet actually is. Starving, in the form of severe calorie restriction, may push your body to unhealthy limits. If you aren’t careful, you could end up suffering from an unhealthy cycle of binging and starving.
Advocates argue intermittent fasting prolongs life, and reduces the risk of cancer, heart disease, diabetes and dementia; however, it is important that claims can be supported by science. Unfortunately, fasting falls short right now. Perhaps the area most subject to debate around fasting is exactly how the process affects men versus women. Research has shown that females will be more susceptible to the long-term consequences of fasting, including but not limited to, hormonal dysregulation, sleep disturbances, fertility issues, and the development of an eating disorders.
Benefits: If you are a fan of eating whatever you want five days per week, this plan will allow you to do just that. You won’t feel like you are on a “diet” with the exception of two days a week, when you are creating a severe calorie deficit through limiting your portions.
Downsides: There is very little sound, proven research on the process of intermittent fasting. Historically, fasting results in weight loss failure as your hunger rebounds on non-fasting days, which can lead to a binge or gorge. Fasting in general may cause irritability, daytime sleepiness or sever energy dips, sleeplessness at night due to an increase in circulating stress hormones, and can possibly lead to dehydration.
The Bottom Line: The biggest concern with this book or approach is leading an individual to believe that you can eat as much as you desire 5 days a week, while severely restricting your food intake 2 days a week. From a behavioral and lifestyle standpoint, you could be creating bad habits and setting yourself up for failure as you begin to experience wide swings with sleep, energy, cravings, and hunger throughout the week.