Fasting – the ultimate diet?

Abstract

SummaryAdult humans often undertake acute fasts for cosmetic, religious or medical reasons. For example, an estimated 14% of US adults have reported using fasting as a means to control body weight and this approach has long been advocated as an intermittent treatment for gross refractory obesity. There are unique historical data sets on extreme forms of food restriction that give insight into the consequences of starvation or semi-starvation in previously healthy, but usually nonobese subjects. These include documented medical reports on victims of hunger strike, famine and prisoners of war. Such data provide a detailed account on how the body adapts to prolonged starvation. It has previously been shown that fasting for the biblical period of 40 days and 40 nights is well within the overall physiological capabilities of a healthy adult. However, the specific effects on the human body and mind are less clearly documented, either in the short term (hours) or in the longer term (days). This review asks the following three questions, pertinent to any weight-loss therapy, (i) how effective is the regime in achieving weight loss, (ii) what impact does it have on psychology? and finally, (iii) does it work long-term?

Anthropometric, Hemodynamic, Metabolic, and Renal Responses during 5 Days of Food and Water Deprivation

“…With weight loss of 1,390 ± 60 g/day, FWD seems to be the most effective dietary protocol, since the magnitude of weight reduction is 50-100% more than observed during juice or water fasting [3,31]. It has to be further investigated whether the impressive weight loss and the remarkable reduction of body circumferences during FWD have any impact on disease risks.…”

Use of the cellular model of body composition to describe changes in body water compartments after total fasting, very low calorie diet and low calorie diet in obese men

“…44 Barnard et al 21 studied seven grossly obese patients fasting for periods between 10 and 45 weeks. Subjects lost on average 35±10% of their weight and FM and ICW accounted for about 50 ± 20 and 22 ± 8% of the weight change, respectively.…”

Fasting vs dietary restriction in cellular protection and cancer treatment: from model organisms to patients

“…Historically, fasting was performed for both medical and religious purposes (Kerndt et al, 1982;Michalsen et al, 2005;Johnstone, 2007). Much has also been learned about the effects of fasting from data on the victims of famine and war (Scrimshaw, 1987;Kalm and Semba, 2005), and also data from subjects fasting voluntarily for 40 days or longer (Kerndt et al, 1982).…”