Forms of intermittent fasting exist in religious practices in various groups across the world. Religious fasting regimens include, but are not limited to, Vrata in Hinduism, Ramadan fasting (Islam), Yom Kippur fasting (Judaism), Orthodox Christian fasting, Fast Sunday (The Church of Jesus Christ of Latter-day Saints), and Buddhist fasting. Certain religious fasting practices, like Buddhist fasting, only require abstinence from certain foods, while others, like the Jewish fast on Yom Kippur, last for a short period of time and would cause negligible effects on the body. Islam is the only major religion that engages in a fasting practice reflective of intermittent fasting in terms of both food consumption and diet consistency. The duration of the Ramadan fast is between 28 and 30 days, depending on the year, and consists of not eating or drinking from sunrise until sunset. During the holiday, Muslims eat twice per day: once in the morning before dawn and once in the evening after dusk. A meta-analysis on the health of Muslims during Ramadan shows significant weight loss during the fasting period of up to 1.51 kilograms (3.3 lb), but this weight was regained within about two weeks of Ramadan ending. The analysis concluded that "Ramadan provides an opportunity to lose weight, but structured and consistent lifestyle modifications are necessary to achieve lasting weight loss." Negative effects of Ramadan fasting include increased risk of hypoglycemia in diabetics as well as inadequate levels of certain nutrients.
At first I questioned, “Is this truly God's call for me?” Forty days was a long time to go without solid food. But with each passing day, His call grew stronger and more clear. Finally, I was convinced. God was calling me to fast, and He would not make such a call without a specific reason or purpose. With this conviction, I entered my fast with excitement and expectancy mounting in my heart, praying, “Lord, what do you want me to do?”
Researchers have demonstrated that fasting counteracts a variety of ailments including cardiovascular disease, diabetes, and even diminishing cognition but these findings were based on studies of rats and other laboratory animals where the researcher controlled the animal’s fast. Even if fasting was as beneficial for humans as it is for rats and mice, the reality is that most of us don’t like to be hungry and there’s no researcher to enforce the fast.
It’s a good idea to weigh yourself before starting (and then again at the same time each week), and also to take chest, waist and hip measurements. The rate that you’ll lose depends on your age, levels of activity and your own body – so don’t be disheartened if you’re losing a pound a week while others are losing five or more. Typically weight loss will be faster at the beginning of the diet, and for those with a lot of weight to lose to reach a healthy weight (see this calculator to find out what a healthy weight - or BMI - is for someone of your height and weight).
Fasting can take some time to get used to, as your body sheds old habits and learns new ones. But listen to your body! If you’re in hour 10 of 16 hours of fasting and feel like you absolutely need a snack, then have one. If your fasting time is up but you’re not hungry yet, wait until you are. There are no hard and fast rules here. You’re not “messing up.” You might find it helpful to jot down a sentence or two each day about how you felt; you might find that certain times of the month or year, different types of fasts work better for you.
Fasting is the willing abstinence or reduction from some or all food, drink, or both, for a period of time. An absolute fast or dry fasting is normally defined as abstinence from all food and liquid for a defined period. Water fasting refers to abstinence from all food and drink except water, but black coffee and tea may be consumed. Other fasts may be partially restrictive, limiting only particular foods or substances, or be intermittent.