Fasting for religious reasons has been done for eons.
In the last centuries, it has been used to lose weight when people finally produced enough food to meet more than their basic needs. Calorie deprivation in some manner is the key to weight loss. The number of diets based on different principles has proliferated over the years. The list is longer than your arm (or waist’s circumference?).
One technique that avoids the prison camp approach of no grub at all is intermittent fasting and eating between fasts. (I’ve always thought it humorous that fasting makes you slow your eating down.)
The patterns employed are: 1) alternate day fasting, or a modified version where 25% of calorie needs are allowed on “lean” days; 2) whole day fasting 1-2 days a week with a bit of vittles allowed, the so-called 5:2 diet popularized several years ago in Britain; and 3) time-restricted feeding involving eating for only a certain time period and having nothing for a longer period, like the 16:8 diet, 8 eight hours of munching followed by nothing for 16 hours.
There are two newer papers on intermittent fasting.
A study from the University of Graz in Austria involved 60 people not overweight and in good health. Thirty were controls for four weeks, eating their usual fare. The other 30 alternated daytime fasting with 12 hours of unrestricted food followed by 36 hours of no food. The assessment at a month was that the fasters had more lean muscle and less body fat, lower cholesterol and improved heart health.
Weekly calories were reduced an average of 37%, and weight loss averaged 7.7 pounds. The controls’ calorie reduction was about 8.2% and weight loss about 0.44 pounds. There were no identifiable ill effects from fasting. This study also followed 30 people who had been doing alternate day fasting for six months and found no detrimental results in them, either.
Three other studies on mice were reported on in the journal Cell Metabolism. These looked at the results of intermittent fasting every other day on immune system white blood cells.
The reason given was that patients with some chronic inflammatory diseases like rheumatoid arthritis and multiple sclerosis have felt their symptoms improve when fasting. One strain of mice with MS symptoms showed improvement with fasting. All the studies had the mice lower calories by 20%, like skipping a meal. To skip the technical details, all three found the T and B lymphocytes or monocytes, both white blood cell types, became less active and circulated less during fasting, which seemed to benefit the cells’ function. No weight loss was calculated. These kinds of data must be applied somehow to humans to be meaningful.
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A very thoughtful Harvard Health Letter from July 2019 briefly reflected on aspects fasting. It cited one JAMA 2017 study of 100 overweight people in three groups over a year: one with restricted daily calories, one doing alternate fasting and one eating as they had. The two diet groups lost weight roughly equally. The 5:2 diet is also mentioned as an option. The director of nutrition at Brigham and Women’s Hospital in Boston said the main goal is to develop a healthy (healthful!) eating pattern that is sustainable and can support weight loss over time. She felt as of now intermittent fasting has not met those criteria.
Certain Internet entries about intermittent fasting glowingly extol its benefits, while others warn of adverse reactions. The main difficulty with any food restriction is how it might affect other medical conditions, such as diabetes or high blood pressure if you take medications that cause potassium loss. Checking with your old doc might be good.
One difficulty is that no studies of intermittent fasting have been done long-term with a lot of cooperative participants.
The other problem is defining what goals are to be achieved, such as weight loss, improved medical status, and currently the effect such fasting has on our gut bacteria or microbiome, which do a lot more to control us than we can imagine.
Claims of benefits with some substantiation are keeping off weight, reducing blood pressure and blood sugar and increasing insulin sensitivity, maybe slowing the aging process (once you’re over the hill, you pick up speed), reducing systemic inflammation and lessening cancer chances. Several entries about intermittent fasting say no real benefits have been documented. Sure, but it might be good for some folks and not others, an idea mentioned in several entries, including the Harvard Letter.
The jokes about diet, obesity and weight loss are legion. One is I like the seefood diet: I see food, and I eat it. I keep losing weight, but it keeps finding me. Or, I’m not overweight, I’m undertall (from a nurse). Chocolate makes my clothes shrink.
The reasons for a variety of diets is that not one is the holy grail for goodies, which lets you eat what you wish and still lose weight. In the late 1930s, my 5-foot-1-inch mom said she went from 225 pounds to 115 in six months by cutting down on all portions in order to get a modeling job in Chicago. Sort of a pre-Weight Watchers technique.
A middle ground approach is to give it a try if you wish. If it’s a good fit for your daily living, it’s a good alternative. There are others. As the sign said in our dietitian’s office: dieting is forever. One more thought: A large study found that women who carried some extra weight lived longer than the men who told them about it…