Protein-sparing modified fast
A protein-sparing modified fast (PSMF) is a type of a very-low-calorie diet (<800 kcal per day) with a high proportion of protein calories and simultaneous restriction of carbohydrate and fat. It includes a protein component, fluids, and vitamin and mineral supplementation.
PSMF diets can last for up to 6 months, followed by a gradual increase in calories over 6–8 weeks.
People on the diet reduce body fat, but the diet is not generally effective in helping achieve durable weight loss.
A PSMF attempts to spare the dieter the health risks of a complete fast by introducing the minimum amount of protein necessary to prevent muscle-wasting effects, while still eliminating fats and carbohydrates. Typically, depending on activity level, 0.8–1.2 g of protein per pound of lean body mass (not total body weight) is consumed. Protein beyond this minimum amount is also eliminated, as the body would use it for energy. Further lean body mass (muscle, organs, etc.) are spared through resistance training and limiting aerobic activity.
The Last Chance Diet
The concept of "protein-sparing modified fast" (PSMF) was described by George Blackburn in the early 1970s as an intensive weight-loss diet designed to mitigate the harms associated with protein-calorie malnutrition and nitrogen losses induced by either acute illness or hypocaloric diets in patients with obesity, in order to adapt the patient's metabolism sufficiently to use endogenous fat stores as well as to preserve the protein contained in the body cell mass.
The "liquid protein" PSMF diet described in the book The Last Chance Diet in 1976, motivates that the liquid protein diets of varying composition became widely popular. Three years later, in 1979, Isner published a report of 17 deaths associated with low-quality liquid protein VLCD, due to heart-related causes. These serious effects caused a substantial concern about the safety of clinical use of PSMF and VLCD. As a result, it was published a review that highlighted the differences with these low-quality liquid protein diets and emphasized the importance of close medical monitoring during the fast and refeeding periods.
Modern PSMF diets
Instead of hydrolyzed collagen, modern medically-supervised PSMF diets include foods of higher biological value, such as meat, fish, eggs, cheese, and/or tofu. PMSF is used as a treatment for highly motivated patients to achieve rapid weight loss and usually is administered for 6 – 16 weeks.
Before an individual starts a PSMF diet, their doctor should order an electrocardiogram, to check for signs of heart disease and also will prescribe specific vitamins minerals and electrolytes to be taken daily as long as the diet persists.
- Atkins diet: a low-carbohydrate diet
- Dukan Diet: a high-protein, low-carbohydrate, low-fat diet
- Intermittent fasting
- Low-carbohydrate diet
- Stillman diet: a high-protein, low-carbohydrate, low-fat diet
- Bal, Bikram S.; Finelli, Frederick C.; Koch, Timothy R. (19 April 2012), "Nutritional Requirements of the Critically Ill Obese Patient", Critical Care Management of the Obese Patient, Wiley-Blackwell, pp. 186–194, doi:10.1002/9781119962083.ch21, ISBN 9781119962083
- Chang, J; Kashyap, SR (September 2014). "The protein-sparing modified fast for obese patients with type 2 diabetes: what to expect". Cleveland Clinic Journal of Medicine. 81 (9): 557–65. doi:10.3949/ccjm.81a.13128. PMID 25183847.
- Gilman SL (2007). Linn, Robert (1933–). Diets and Dieting: A Cultural Encyclopedia. Routledge. p. 160. ISBN 978-1-135-87068-3.
- Manninen, Anssi (2006). "Very-low-carbohydrate diets and preservation of muscle mass". Nutr Metab (Lond). 3: 9. doi:10.1186/1743-7075-3-9. PMC 1373635. PMID 16448570.
- Bryner, Randy. "Effects of Resistance vs. Aerobic Training Combined With an 800 Calorie Liquid Diet on Lean Body Mass and Resting Metabolic Rate". researchgate.net. ResearchGate. Retrieved 10 July 2017.
- Blackburn, C. L.; Flatt, J. P.; Clowes, G. H. A.; Oʼdonnell, T. F.; Hensle, T. E. (May 1973). "Protein Sparing Therapy during Periods of Starvation with Sepsis or Trauma". Annals of Surgery. 177 (5): 588–94. doi:10.1097/00000658-197305000-00012. ISSN 0003-4932. PMC 1355601. PMID 4634108.
- Thomas, Dylan D.; Istfan, Nawfal W.; Bistrian, Bruce R.; Apovian, Caroline M. (February 2018). "Protein sparing therapies in acute illness and obesity: a review of George Blackburn's contributions to nutrition science". Metabolism. 79: 83–96. doi:10.1016/j.metabol.2017.11.020. PMC 5809291. PMID 29223678.
- Engelman, Ralph (July 1989). "Joseph C. Goulden. Fit to Print: A.M. Rosenthal and His Times". American Journalism. 6 (3): 202–204. doi:10.1080/08821127.1989.10731199. ISSN 0882-1127.
- Isner, J M; Sours, H E; Paris, A L; Ferrans, V J; Roberts, W C (December 1979). "Sudden, unexpected death in avid dieters using the liquid-protein-modified-fast diet. Observations in 17 patients and the role of the prolonged QT interval". Circulation. 60 (6): 1401–1412. doi:10.1161/01.CIR.60.6.1401. ISSN 0009-7322.
- Bistrian, Bruce R. (17 November 1978). "Clinical Use of a Protein-Sparing Modified Fast". JAMA: The Journal of the American Medical Association. 240 (21): 2299. doi:10.1001/jama.1978.03290210081040. ISSN 0098-7484.