The Fast-5 Diet refers to the way of eating endorsed by Bert Herring M.D. in the book "The Fast-5 Diet and the Fast-5 Lifestyle." The Fast-5 Diet is a weight-loss and weight-maintenance plan consisting of a single rule: limit calorie intake to no more than five consecutive hours in each day. The Fast-5 Lifestyle is an indefinite continuation of the diet for weight maintenance after the weight loss goal has been reached.

Origins

The Fast-5 diet was developed based on the personal results Herring experienced while working at the National Institutes of Health and incorporates estimates of the eating schedule of ancient hunter-gatherer

Hunter-gatherer

A hunter-gatherer or forage society is one in which most or all food is obtained from wild plants and animals, in contrast to agricultural societies which rely mainly on domesticated species. Hunting and gathering was the ancestral subsistence mode of Homo, and all modern humans were...

 humans who ate without benefit of food storage or refrigeration.

Theory

Herring's premise for the Fast-5 Diet is that adipose tissue

Adipose tissue

In histology, adipose tissue or body fat or fat depot or just fat is loose connective tissue composed of adipocytes. It is technically composed of roughly only 80% fat; fat in its solitary state exists in the liver and muscles. Adipose tissue is derived from lipoblasts...

 (fat cells) cannot burn fat as fuel at the same time it is storing fuel produced by digestion of food. The restriction of calorie consumption to the five-hour window is intended to increase the time when the digestive tract is empty so no fuel is being provided by digestion. In this fasting phase, insulin

Insulin

Insulin is a hormone central to regulating carbohydrate and fat metabolism in the body. Insulin causes cells in the liver, muscle, and fat tissue to take up glucose from the blood, storing it as glycogen in the liver and muscle....

 is at low (nadir) levels and the body is dependent on the release of stored fat and glycogen

Glycogen

Glycogen is a molecule that serves as the secondary long-term energy storage in animal and fungal cells, with the primary energy stores being held in adipose tissue...

 for energy. By extending the interval between meals, Herring suggests some benefits characteristic of intermittent fasting

Intermittent fasting

Intermittent fasting is a pattern of eating that alternates between periods of fasting and non-fasting. A specific form of IF is alternate day fasting , which is a 48-hour routine typically composed of a 24-hour fast followed by a 24-hour non-fasting period...

 and calorie restriction

Calorie restriction

Caloric restriction , or calorie restriction, is a dietary regimen that restricts calorie intake, where the baseline for the restriction varies, usually being the previous, unrestricted, intake of the subjects...

 may be achieved.

Practice

Herring suggests an eating window of 5pm - 10pm but indicates that the nineteen continuous hours of fasting time is the key to the diet's effect. The five-hour eating window may be set when it is most convenient. The Fast-5 approach does not stipulate a calorie intake level; it relies on the eating schedule's effect of correcting appetite to determine proper intake. The Fast-5 Diet also does not specify food content or forbid any foods, allowing the approach to be used with any dietary preference (e.g., Kosher, vegetarian, or the diet recommended by the American Heart Association

American Heart Association

The American Heart Association is a non-profit organization in the United States that fosters appropriate cardiac care in an effort to reduce disability and deaths caused by cardiovascular disease and stroke. It is headquartered in Dallas, Texas...

).

Public Review and Comment

The Fast-5 Diet was the subject of a news report from WPVI-TV

WPVI-TV

WPVI-TV, channel 6, is an owned-and-operated television station of the Walt Disney Company-owned American Broadcasting Company, located in Philadelphia, Pennsylvania, USA. WPVI has its studios located on the border between Philadelphia and Bala Cynwyd, and its transmitter is located in the...

 in Philadelphia including a month-long trial by two volunteer testers, a WKMG-TV

WKMG-TV

WKMG-TV channel 6 is the CBS network affiliate for Central Florida . WKMG is licensed to Orlando and is owned and operated by Post-Newsweek Stations, Inc., a subsidiary of the Washington Post Company. The station refers to itself as "Local6". WKMG's transmitter is located in Bithlo, Florida...

 Orlando news report, a WJXT

WJXT

WJXT, channel 4 , is an independent television station serving Jacksonville, Florida, and surrounding communities. Its transmitter is in the Kilarney Shores section of Jacksonville, with the WTLV transmitter. The station originally broadcast an analog signal on VHF channel 4 and a digital signal...

Jacksonville news report, and a report in the Florida Times-Union.

External links

• http://www.fast-5.com www.fast-5.com
• http://abclocal.go.com/wpvi/story?section=news/special_reports&id=7357401 WPVI-TV Philadelphia Report
• http://www.clickorlando.com/video/23074122/index.html WKMG-TV Orlando Report
• http://www.youtube.com/watch?v=IulpmWPRL2U WJXT-TV Jacksonille, Fla. Report on YouTube
• http://jacksonville.com/community/the_sun/2009-12-19/story/two_jacksonville_doctors_create_new_weight_loss_plan Jacksonville.com / Florida Times-Union Report
• http://www.amazon.com/Diets-Hollywood-That-Money-ebook/dp/B003VIWQ5A/ Hollywood Diets That Work