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8. Intermittent Fasting--Another Way to Provoke the Starvation Response and Ruin Your Metabolism. Intermittent fasting diets like the 5:2 Diet are very popular now but most of us who have tried them for extended periods of time have learned they have all the problems seen with other extreme diets, though they don't seem like starvation diets, as you can eat "normally" when not fasting.
Encouraged by the success reported by some people I trust, I tested out a very strict 5:2 Fast Diet for two years. It took the whole two years for me to see the toll that this kind of dieting took on my body. During the two years I participated daily in an active online fasting-support group where I observed that the ultimately negative outcome I experienced was what most of the dedicated participants in the online group experienced: Very good weight loss results for the first seven months were followed by a sudden reversal where I first stalled and then then began to gain weight relentlessly eating exactly the way I'd been eating while losing so quickly. Worse, my appetite went out of control and by the end of the two years I had developed what felt like a binging disorder.
This was something I had never before experienced in 65 years of controlling my weight with various diet approaches, including 11 years of maintaining a substantial weight loss achieved eating a very low carb diet featuring occasional days off. At the end of my 2 years of intermittent fasting I ended up with far more jiggly subcutaneous fat than I had started with, even though I ended up at the same weight I started at.
I believe this happened because fasting lowered my estrogen levels dramatically.
This was evidenced by my developing menopausal symptoms after a year on the diet--a decade after last experiencing them, at the same time as the diet had, indeed gotten rid of subcutaneous tummy fat.
It took me a good year to get back to having a normal relationship with my appetite. During that year I had to give up entirely on dieting in any way. The tummy fat seems to have moved in permanently.
This experience was very much like what I saw others experience, too, including personal friends and people on the online support group. To me this suggests that long-term intermittent fasting changes your brain chemistry and hormonal balance in a way that makes it much more likely that you will eventually run into this kind of problem.
If you are considering trying intermittent fasting be aware that all the research that is currently used to promote fasting by the usual suspects who get rich selling celebrity doctor diet books is based on very short studies which lasted only a few weeks or, at most, months. Almost all the studies on fasting looked at the physiological changes caused by very short stints of medically supervised complete fasting. Almost none examine the kinds of intermittent fasting dieters use in the currently popular diets like 5:2. The truth is, there is zero data about the long term experience of intermittent fasters.
The sad outcomes most people in my online fasting support forum experienced and my own results suggest that the outcomes over extended periods of time are mostly poor.
Eating a low carb intermittent fasting diet doesn't seem to produce better results, either, based on the reports of those on the fasting support group, who were eating that way.Those dieters stalled and regained on very low carb diets too.
My experience and that of participants in low carb diet support groups suggest that those who figure out a way to cut carbs in a way that doesn't make them feel deprived are able to stick to their diets for far longer with much better results and, most importantly, without the rebound hunger and metabolic slowdown that is so characteristic of more extreme diets. It's worth noting, however, that my polling of those who ate low carb diets for extended periods after achieving weight loss goals showed that most of the successful dieters who did this maintained eating at a non-ketogenic intake level--one close to 110 g a day. It is possible that extended ketogenic dieting may also provoke the starvation response in some people.