5-Factor Diet


The 5-Factor diet is part of an overall healthy lifestyle and fitness program devised by Harley Pasternak (1974–), a Canadian-born personal trainer for celebrities, as well as a nutrition and fitness expert. The diet regimen includes recommendations about exercise and cooking shortcuts, as well as meal plans and recipes. The diet itself is essentially a moderate-carbohydrate, high-fiber, and high-protein regimen that incorporates the glycemic index (GI) as a guide to choosing appropriate foods.


The 5-Factor diet originated with Harvey Pasternak, a Canadian-born and -educated sports and fitness expert who began his career as an exercise and nutrition scientist for Canada's Defence and Civil Institute for Environmental Medicine (DCIEM), where he worked between 2005 and 2007. Pasternak is somewhat unusual for writers of popular diet books in that he holds several academic credentials in physiology and nutrition. He completed high school at York Mills Collegiate Institute in Toronto and earned a master's degree in exercise physiology and nutritional science from the University of Toronto. Pasternak also holds a degree in kinesiology from the University of Western Ontario in London, Ontario. He has been certified as a personal trainer and health/fitness instructor by the American College of Sports Medicine (ACSM) and the Canadian Society for Exercise Physiology (CSEP).

Following his work with DCIEM, Pasternak became a personal trainer. His first book, published in 2004, was primarily concerned with fitness and exercise, along with some advice about diet and nutrition. The first two parts of the book were about fitness workouts, with an early version of the 5-Factor diet added as Part 3, titled “5-Factor Fuel.” Pasternak's 2006 book is essentially an expansion of the third section of the earlier book with the exercise component reduced to a single chapter, “The New 5-Factor Hollywood Workout,” and additional chapters on food selection and recipes. According to the introduction of The 5-Factor Diet, Pasternak struggled with weight issues himself as a youth and became motivated to learn more about nutrition, human metabolism, and exercise at the graduate level not only because of his own weight problem but also because his two younger brothers had been diagnosed with type 1 diabetes.

According to Pasternak, the fitness program that he devised as a personal trainer brought him to the attention of a number of Hollywood and media celebrities who “wanted to tone up for upcoming roles.” In addition to mentioning the names of some of these actors and musicians, Pasternak states that he wrote his 2006 book in response to “more than 5,000 e-mails from people who had purchased 5-Factor Fitness…and wanted to know more about the 5-Factor Diet.” Pasternak has since become a minor media celebrity in his own right, as a frequent guest on daytime talk shows and cohost of a short-lived health and lifestyle daytime television show on the ABC network called The Revolution, which aired from January to July 2012.


As its name suggests, the 5-Factor diet is based on the number five, which is featured in the accompanying exercise program as well as the diet itself. The basic outline of the 5-Factor diet is to eat five meals per day, one every three to four hours (breakfast, a snack, lunch, a second snack, and dinner). Each meal is to contain only five main ingredients, take only five minutes to prepare, and to contain five components: a complex carbohydrate, a lean protein, a sugar-free beverage, fiber, and a “good” fat.

The 5 Factor Diet provides five weeks of meal plans and recipes. A typical recipe, “Greek Pizza Roll Ups,” uses the following ingredients:

The instructions are equally simple:

Pasternak maintains that regular exercise is 50% of his weight-loss plan. The number five reappears in the form of five exercises to be performed for 5 minutes each for five days of the week, for a total of 25 minutes of physical exercise per day. The book includes photographs, as well as step-by-step instructions for the fitness exercises, which are a combination of cardiovascular and strength training: a cardiovascular warm-up, upper-body strength exercises, lower-body strength exercises, exercises for the core muscles, and a cardiovascular workout.

One distinctive feature of the 5-Factor diet is what Pasternak calls the “cheat” day: one day a week in which the dieter is free to eat favorite dishes that do not fit the 5-factor template, such as fried chicken legs or a glass of beer. Some dieters who feel deprived on less flexible diet plans may find that the “cheat” day will help them stick with the 5-Factor diet.


The 5-Factor diet is essentially a moderate-carbohydrate, high-fiber, and high-protein diet combined with an exercise program intended to promote a moderate rate of weight loss and the adoption of more healthful eating habits in otherwise healthy people. It is not intended to treat any chronic medical conditions or disorders.

Glycemic index (GI)—
A system devised at the University of Toronto in 1981 that ranks carbohydrates in individual foods on a gram-for-gram basis with regard to their effect on blood glucose levels in the first two hours after a meal. There are two commonly used GIs, one based on pure glucose as the reference standard and the other based on white bread.
Very low-calorie diet (VLCD)—
A term used by registered dietitians to classify weight-reduction diets that allow around 800 calories or fewer a day.


The American Academy of Nutrition and Dietetics' (formerly the American Dietetic Association) review of the 5-Factor diet recommends the plan as “a good, simple idea that sends a healthy message: Eat a variety of foods in appropriate amounts and you'll lose weight, be healthy and probably get most of the vitamins and other nutrients you need from your food.” Other reviewers have noted that the 5-Factor diet is not a fad diet, as it does not exclude any basic food groups, allows users to adapt meal plans to their own tastes and preferences, and includes a regular workout program. Users of the diet will lose weight slowly rather than rapidly—an average of one or two pounds per week, which is not only healthful but better for long-term weight management than rapid weight loss.


Although the 5-Factor diet is not a very low-calorie diet (VLCD), it is always a good idea for people who need to lose 30 pounds or more, are pregnant or nursing, are below the age of 18, or have a chronic disorder to check with their physician before starting any weight-reduction diet. The 5-Factor diet is not a good choice for people with diabetes, hypertension, or kidney disease.

Although Pasternak's book suggests five weeks as the duration of the diet, most reviewers have observed that anyone with more than 10 pounds to lose will need to remain on the diet longer than five weeks to reach their desired weight. The 5-Factor diet is considered safe for long-term use.


Other criticisms of the diet include its lack of guidance for eating out; users are left on their own to estimate what restaurant foods might fit the 5-Factor pattern. In addition, the diet may not work well for people who are emotion-driven eaters or for those whose work and travel schedules make it difficult to eat or prepare five meals a day at Pasternak's recommended time intervals.


Some registered dietitians maintain that the 5-Factor diet is not appropriate for people with the following chronic health conditions:

Research and general acceptance

One common criticism of the 5-Factor diet is its lack of clinical testing or other scientific evidence. No studies of the diet had been published in the mainstream medical literature as of 2018, which is ironic given Pasternak's academic background in nutrition and sports medicine. He is listed in the National Library of Medicine database as a coauthor on one scholarly article, a study of the effects of ephedrine and caffeine on muscular endurance that was published in 2003.

In addition to the absence of clinical studies of the 5-Factor diet, other dietitians have pointed out that the glycemic index, which is a prominent feature of Pasternak's diet, is controversial as a guide to weight loss for people without diabetes. Some researchers maintain that the total amount of carbohydrate in a person's diet is a more accurate indicator of nutritional status than the GI values of specific foods.

In addition to the lack of scholarly studies of the 5-Factor diet, Pasternak's role as a media star and his liberal use of celebrity endorsements has been criticized as diverting attention from the diet's genuine good points. A reviewer for the Academy of Nutrition and Dietetics remarked, “I wish every other page didn't quote celebrities in big letters about how wonderful the author and diet are. This makes the book seem gimmicky and less credible, which is unfortunate since the diet plan is quite good.”

See also Academy of Nutrition and Dietetics ; Caffeine ; Carbohydrates ; Metabolism ; Protein ; Vitamins .



Pasternak, Harley, and Ethan Boldt. 5-Factor Fitness: The Diet and Fitness Secret of Hollywood's A-List. New York: G.P. Putnam's Sons, 2004.

Pasternak, Harley, with Laura Moser. The 5-Factor World Diet. New York: Ballantine Books, 2009.

Pasternak, Harley, with Myatt Murphy. The 5 Factor Diet. Des Moines, IA: Meredith Books, 2006.


Jacobs, I., H. Pasternak, and D. G. Bell. “Effects of Ephedrine, Caffeine, and Their Combination on Muscular Endurance.” Medicine and Science in Sports and Exercise 35, no. 6 (June 2003): 987–94.


Bledsoe, Andrea. “The 5 Factor Diet.” EverydayHealth.com . http://www.everydayhealth.com/diet-nutrition/5-Factor-diet.aspx (accessed April 24, 2018).

Schweitzer, Lisa. “The 5 Factor Diet.” WebMD.com . https://www.webmd.com/diet/a-z/5-factor-diet (accessed April 24, 2018).

Scott, Jennifer R. “How to Follow the 5 Factor Diet Plan.” https://www.verywellfit.com/informationabout-the-five-factor-diet-3496188 (accessed April 24, 2018).

Sher, Lauren. “Get Fit in 2012 with Harley Pasternak's Full Body Toning Tips.” ABC News, December 22, 2011. https://www.yahoo.com/gma/fit-2012-harleypasternaks-full-body-toning-tips-221224953.html (accessed April 24, 2018).


Academy of Nutrition and Dietetics, 120 South Riverside Plz., Ste. 2000, Chicago, IL, 60606-6995, (312) 899-0040, (800) 877-1600, amacmunn@eatright.org, http://www.eatright.org .

Canadian Society for Exercise Physiology (CSEP), 18 Louisa St., Ste. 370, Ottawa, Canada Ontario, K1R 6γ6, (613) 234-3755, (877) 651-3755, Fax: (613) 234-3565, info@csep.ca, http://www.csep.ca/english/view.asp?x=1 .

Rebecca J. Frey, PhD

  This information is not a tool for self-diagnosis or a substitute for professional care.