Fasting can mean anything from total abstinence from food and beverages to restricting specific foods or the hours of food intake. Many religions have traditions of fasting, with various restrictions. There is a good summary of those traditions on Wikipedia. The reason for religious fasting is not to improve health, but for other reasons like improving discipline and demonstrating devotion.
There are many health claims for different fasting regimens. Daily calorie restriction has been demonstrated to prolong lifespans in several organisms, from yeast and worms to mice and monkeys, although the evidence for monkeys is equivocal and there is no evidence for humans. There is some evidence that intermittent fasting can forestall and even reverse cancer, cardiovascular disease, diabetes, and neurodegenerative disorders in mice. In humans, there is some evidence that it might help reduce obesity, hypertension, asthma, and rheumatoid arthritis. How good is the evidence? (more…)
Isagenix is a wellness system sold by multilevel marketing. It consists of a suite of products to be used in various combinations for “nutritional cleansing,” detoxification, and supplementation to aid in weight loss, improve energy and performance, and support healthy aging. It allegedly burns fat while supporting lean muscle, maintains healthy cholesterol levels, supports telomeres, improves resistance to illness, reduces cravings, improves body composition, and slows the aging process. And makes millions for distributors who got on the bandwagon early and are high on the pyramid.
I have written about it before and have been roundly criticized by its proponents. It generated my all-time favorite insult: “Dr Harriet Hall is a refrigerator with a head.”
My biggest concern with Isagenix was that it had not been clinically tested. They claimed that clinical tests were in progress (funded by Isagenix). An e-mail correspondent recently told me I should take another look at Isagenix, since a clinical study had been completed. It had not yet been published, and I asked her to get back to me when it was. Ask and you shall receive (but you may be sorry!). She contacted me when the study by Kroeger et al. was published in the journal Nutrition and Metabolism. The full study is available online and I urge readers to click on the link and look at Table 2, which I will be referring to later. The journal is peer-reviewed but, as will become painfully obvious, the peer reviewers did not do a competent job. It is an open-access online journal with a low impact factor. The authors had to pay to get their article published: it cost them $1805.