Fast 5:2 Diet

Nearly every day a new story breaks about obesity and the harm it can cause. To address this problem, diet and fasting have become the topics of conversation and the subjects of numerous magazine and newspaper articles, books, and self-help videos.

Fasting promises to destroy excess fat, improve health outcomes, and lengthen lives. Research has indicated that fasting from time to time decreases the amount of body fat, lowers insulin levels, and offers general health benefits.

While there may be many avenues to fasting, the Fast 5:2 Diet allows participants to eat normally five days out of the week. The other two days requires that the participant restrict consumption to no more than 600 calories daily. This is significantly less than the amount that the average American eats, comprising only about a fourth of ordinary caloric intake. But it does not mean starving yourself to happiness.

Intermittent fasting trend

The concept of fasting periodically seems to be making progress. Dr Michael Mosley first brought the diet regime of fasting for two days and eating normally for the other five days to the attention of the public in a BBC documentary series and book in January 2013.

Michael Mosley The Fast Diet

This was followed by another book, 5:2 Diet Book, authored by Kate Harrison, which claims that it is possible to transform one’s health for the better by enjoying a regular diet for five days and fasting for two.

The Fast 5:2 diet can be considered part of the evolving trend of intermittent fasting. Proponents of taking periodic breaks from regular eating habits, for one to two days per week, claim the approach can help one effectively reduce their weight, and that research backs this up. It is true that a fair amount of research does support the health benefits of fasting, but much of the work has focused not on humans, but on animals instead.

Promising results

Still, research results hold out promise. Fasting has the potential to optimize the levels of disease biomarkers, and  lower levels of oxidative stress, as well as maintain learning and memory function. Scientists at the US-based National Institute on Aging, part of the National Institutes of Health, have looked into how intermittent fasting impacts the cardiovascular system and brain in rodents. The need now is for well-controlled human studies in subjects covering a wide range of body mass indices (BMI).

Theories abound about how fasting yields physiological benefits. Among them is the belief that during fasting, cells experience some stress. The cells respond by improving their capability to deal with the stress and possibly resist illness.

Moreover, a UK-based study, led by the Genesis Breast Cancer Prevention Center at University Hospital of South Manchester NHS Foundation Trust, determined that there were changes in the breast cells of some women who followed the Fast Diet, which may be indicative of protection against breast cancer. However, some questions remain as the study contained only a small number of participants and was short in length.

The study involved two dozen middle-aged overweight or obese women who did not have cancer nor diabetes, but whose risk for breast cancer was higher than average. The participants were instructed to decrease their caloric consumption by three-quarters for two consecutive days a week and for the following five days to consume a Mediterranean diet, which might consist of fish, vegetables, and starchy foods.

The participants lost about 5% weight and body fat and experienced changes for the better in the metabolism of fat, insulin, and energy. About 50% of participants underwent biochemical changes in breast tissue, which scientists saw as possibly related to their risk for developing breast cancer. The observed changes fall short of showing that the 5:2 diet lessens the potential for breast cancer in women. However, the risk for breast cancer can be lessened by losing weight.

Some concerns

There are concerns that benefits of the Fast 5:2 Diet are exaggerated, and that there may be possible risks. Fasting is popular, to the point of being a fad. Fads are dismissed by physicians and nutritionists, which might mean that patients could miss any legitimate benefits of proper fasting. Yet another issue is that proponents of intermittent fasting might be suggesting that bingeing is permissible – that it is okay to consume high-calorie or fatty foods two days a week, if people cut back the other five days.

Essentially though, the concept behind intermittent fasting is to use common sense when eating on the five days when normal eating is allowed, and only indulge occasionally, claim its proponents.



Further Reading

Last Updated: Dec 29, 2022

Joseph Constance

Written by

Joseph Constance

Joseph Constance has written about research, development, and markets in the health care and related fields. He has authored a number of articles, and business analysis/market research reports in the medical device, clinical diagnostics, and pharmaceutical areas. Joseph holds an MA from New York University in Communications. He enjoys spending time with his wife, biking, traveling, and learning about different cultures.


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