Fasting (October 28, 2014)
Last week I talked about a recent study that found people who lost weight rapidly were not only more likely to achieve a 12.5% weight loss than those who lost it slowly, but were just as likely to keep that weight off, dealing the popular wisdom that losing weight more slowly is best a knockout punch. Well, maybe not that exactly, but it IS down for the count at this point.
I found something a little odd about this study, though. It deems “rapid” weight loss to be a loss of 12.5% of the individual’s body weight in 12 weeks. For someone 180 pounds, this would be 22.5 pounds in 12 weeks, or less than 2 pounds a week. That doesn't sound very "rapid" to me. RAPID weight loss would be more like 10-25 pounds over two weeks or so, and that is what you get from fasting. Fasting has been done in various forms to treat many conditions besides obesity (as well as for spiritual reasons) for a very long time and could fairly be termed a traditional therapy.
Fasting is a rather elastic term for any temporary style of eating that severely limits food and drink in some fashion or another, and there are no end of variations on what is consumed, how long the restriction continues, and whether the fast is continuous or intermittent. The medical definition of fasting is simply consumption of fewer than 600 calories daily, and good luck finding a conventional doctor to support you in one, even grudgingly. That misguided prejudice is probably why relatively little scientific research has been done on fasting until fairly recently.
Fasting has often been done in the past to treat arthritis, particularly severe cases of same. That makes sense when we see that decreases in general inflammation and increases in insulin sensitivity have both been found in people on fasts. People who fasted for 24 hours per week for six weeks (the metabolic state seen in fasting begins 8-12 hours after consumption of your last meal, so that would be eating dinner then not eating again until the morning after next) saw improvements in cellular metabolism after just that short a time. People who have fasted one day a month for many years exhibit lower incidences of both heart disease and diabetes. Specific changes seen include reduction in weight (even with the relatively infrequent fasting) and in LDL cholesterol levels, insulin resistance, glucose levels, blood pressure and triglycerides.
I think very highly of fasting as a tool for health. In my misspent youth I once did a one-month juice fast, and have done shorter fasts from time to time through the years. For some reason they are getting harder and harder to do, so I was very intrigued when I first heard about intermittent fasting. So far it seems to be just as effective as a continuous diet in losing weight, and even better at normalizing blood levels of sugar and fats. (We're talking about fasting every other day here.) Additionally there is evidence of the same cardiovascular benefits I mentioned a little earlier, and also in normalizing immune response in those with autoimmune problems. PLUS -- continuous severe calorie restriction has been shown to extend life in mice, and intermittent fasting has shown those same metabolic changes, in mice AND in humans.
If you are fasting for rapid weight loss, there are a few issues that might come up, especially at the beginning until you get used to that whole "not eating" thing. (The psychological stress of not eating is usually a lot rougher than the physical stress.) Most of these (dehydration, malnutrition, muscle and hair loss, fatigue and electrolyte imbalances) are easily avoidable in an intermittent fast, and at this point if you find the idea of fasting at all attractive, I would unhesitatingly recommend looking into the intermittent type.
--dr. diane holmes
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