UK’s “Fast Diet”? Not So Fast

UK's newest diet craze is bringing intermittent
fasting into the mainstream, but it has some
drawbacks.

The Fast Diet (1), a UK best-selling book that has just been published in the U.S., promises that you can eat whatever you want, but still lose weight, and even live longer as long as you employ “intermittent fasting.” Ah, now you see the connection—Isagenix has been extolling the virtues of intermittent fasting (as “Cleanse Days”) for more than a decade.

There’s something oddly familiar about the premise of Britain’s latest diet craze that is now reaching U.S. shores, wouldn’t you think?

What’s more is that the book outlines a 5:2 approach—unrestricted eating for five days of the week and two non-consecutive days spent fasting, which counts as 500 calories a day for women and 600 calories a day for men. That’s somewhat similar to the Isagenix plan, which encourages adoption of Shake Days for five to six days and one or two Cleanse Days per week.

In their book, Dr. Michael Mosley and Mimi Spencer do a fine job building a case for intermittent fasting as a method for better weight-control, improved health, and even longer life. For example, they review the research produced by nutritionist Krista Varady of University of Illinois at Chicago, who was the principal investigator for UIC’s study evaluating Isagenix products. They also discuss the findings of Dr. Valter Longo and Mark Mattson in rodents that show that calorie restriction and intermittent fasting can potentially protect the brain and increase lifespan.

However, the weight-loss plan has had critics putting up their warning signals and for good reason:

• Eating whatever you want (and as much as you want) has its consequences. One of the biggest negatives is the endorsement to eat without restraint for five days of the week. The book does propose some healthy eating guidelines, but with the main attraction being Eat anything you want!, there’s likelihood that many people will live by those words. That kind of promotion is bound to be harmful as people are given license to grossly overeat and to eat the wrong types of foods as often as possible—think greasy hamburgers, French fries, and sugary sodas as much as possible! Even two days of intermittent fasting can’t undo a lifetime of making unhealthy choices like these.
• Another problem is potential muscle loss. When the body is taking in fewer calories, it goes into what’s called a catabolic state (meaning “breakdown”; the opposite is anabolic, which means “build-up”). Catabolism is fine for the breakdown of fat, but if calorie-deficient bouts are not followed up with the right type of muscle-building protein in the right amount, the result can be breakdown of muscle. Studies have found that during weight loss, a diet higher in quality protein preserves muscle mass more than a diet higher in carbohydrate (2). Research has also found that protein from dairy, such as whey, may be the superior protein for increased fat loss and muscle retention during weight loss (3).
• Then, there’s the issue of complete nutrition. As we’ve mentioned many times in previous articles, most Americans already eat too much, yet do not receive adequate amounts of micronutrients (vitamins and minerals) from their foods for optimal health. Mainly, this is because too many people don’t eat enough fruits and vegetables or may not know how to properly choose foods for adequate amounts of micronutrients. Even those who think they know what foods to eat in combination for better health haven’t fared well in achieving weight loss and improved health. One study compared weight loss groups consuming either fresh, healthy foods for the majority of their diet or nutrient-rich meal replacement shakes and found that meal replacement shakes resulted in more weight loss, better improvement to health biomarkers, and better adherence based on the convenience of the shakes (4).

How can you take advantage of the benefits of intermittent fasting without the drawbacks of the 5:2 diet approach that include eating too much, losing muscle, and not getting enough vitamins and minerals? Look to Isagenix for the perfect program that takes the guesswork out of intermittent fasting and how to do it right.

What you get with Isagenix is intermittent fasting fully prepped for as Cleanse Days, which are part of a fully guided system that won’t leave you eating everything in sight one day followed by wanting to eat your arm off the next. An Isagenix system means moderate calorie control on Shake Days and appropriate fasting with nutritional support on Cleanse Days.

The Isagenix system, unlike The Fast Diet, is also backed by clinical data showing that it leads to healthy weight loss, fat loss (without the muscle loss, especially if exercise is included), and better cardiovascular health. The end result is curbed food cravings, successful weight loss and maintenance, preservation of muscle mass, and finally, a long-term lifestyle that will get you healthier than ever before.