Most religions prescribe periods of fasting as a means of demonstrating faith or repentance as well as creating opportunities for spiritual reflection. Fasting also has historically been a means to express political views and protest.
Although this may not be the most practical and safest diet, some people use fasting as a way to lose weight or to cleanse the body of toxins. However, some experts say that our bodies are well equipped with organs that are already doing that job quite handily. The ways that fasting is used as a weight loss diet varies greatly. Some fasting diets involve drinking only water while others involve eating only raw foods for one or more days. Other fasting diet types restrict food throughout the day. Certain fasting diets restrict fluid intake to water, juice or tea, while others sharply reduce calories, but do not eliminate food in general.
Will Fasting Help You Lose Weight?
When you fast, your body is forced to dip into energy stores to get the fuel it needs to keep going, and this can lead to rapid weight loss. The big question is how fast you will lose weight. Since our ancestors typically did not get enough to eat, our bodies are genetically programmed to fight the effects of fasting. In fact, when you eat less food, your metabolism slows down to conserve your energy. Then, when you return to your normal diet, your decreased metabolism can cause you to store more energy, meaning that you are likely to gain back the weight you lost and maybe even put on more weight. Note that this can occur even if you consume the same amount of calories you did before you dieted.
As you fast, your body will adjust by reducing your appetite, so you initially feel less hungry. But once you stop fasting, your appetite hormones kick into high gear, and you can actually feel more hungry. The bottom line is that you will be more likely to binge.
Studies have shown that fasting every other day can help people lose weight, but not for long. In one study, people who followed the every other day fasting diet shed weight, even when they ate all they wanted during the day. However, they could not maintain the weight loss over time.
Can Fasting Detoxify the Body?
Some diet plans that recommend fasting claim that their diets can rid the body of impurities. However, there is no evidence that fasting detoxifies the body, or that the body even needs to be detoxified in the first place. The body already contains organs that can detoxify the blood on a regular basis. Three of these organs: the skin, the liver and the kidneys.
Could Fasting Help You Live Longer?
Research on fasting in rodents as well as humans seems to indicate a connection between calorie restriction and longevity. In one study conducted on overweight men and women, calorie restriction improved aging markers such as insulin levels and body temperature.
Fasting may also improve durability, delaying the onset of age-related diseases such as Alzheimer’s disease, heart disease and diabetes. One study found that skipping a meal once a month, as members of the Mormon religious groups do, reduces the risk of clogged arteries (plaque buildup that can lead to heart attacks and strokes). However, it is not clear from this study whether the fasting is responsible for the weight loss. Mormons also traditionally abstain from coffee, alcohol and smoking.
Researchers do not yet know whether the effects of fasting translate into an actual increase in life expectancy because they did not follow people for a long enough period of time. However, fasting for weightless is a provocative notion. Fasting seems to be a relatively safe way to reduce caloric intake. However, fasting for weight loss has not yet gained wide-spread acceptance.