But followers beware, says nutrition researcher Michelle Harvie. Dieters going keto tend to lose weight, but the diets are low in fiber and high in saturated fat, which is a risk for cardiovascular disease. “And there is increasing evidence that its effect on the gut microbiome is pretty adverse,” says Harvie. “The gut microbiome is a poorly understood but potentially important part of our metabolic health. And if you mess that up, you’re in trouble.”
Of the two most popular methods, Sasson leans toward the 5:2 schedule as slightly more manageable, since you’re only reducing your intake twice a week. But again, that’s contingent on you being a responsible dieter on your days of lowered caloric intake, which requires an immense amount of discipline—especially when it comes to remembering to drink water. “You can go a long time without food, but only a few days without adequate hydration,” she warns.
That’s what happened to me. I was in ketosis for a year, lost 125lbs, but then I started eating again and poof, back came 90 of the 125 pounds 🙁 I’m finding it more difficult to get back into the swing of eating under 20 carbs a day. I find myself starving, or carb starved as it’s called, and it’s proving to be difficult, even with the meal replacement drinks. I’m going to try this fasting and see if that will help me get back to skinny, but be able to keep it off.
Keep in mind that the initial weight lost on a fast is primarily fluid or "water weight," not fat. And when you go back to eating, any lost weight usually gets a return ticket back. Not only do most people regain weight lost on a fast, they tend to add a few extra pounds because a slower metabolism makes it easier to gain weight. Worse, the weight that is regained is likely to be all fat -- lost muscle has to be added back at the gym.
AN IMPORTANT CAVEAT: Intermittent Fasting can be more complex for people who have issues with blood sugar regulation, suffer from hypoglycemia, have diabetes, etc. If you fit into this category, check with your doctor or dietitian before adjusting your eating schedule. It also affects women differently (there’s a whole section dedicated to that below)
Fasting in the Ethiopian Church implies abstention from food and drink. No animal products are consumed, including dairy, eggs and meat, and utensils that have touched such products must be washed before touching the strictly vegan foods that are consumed on fast days. During fast periods, Holy Liturgy (Mass) is held at noon (except on Saturdays and Sundays), and because no food can be consumed before communion, it is traditional for people to abstain from food until mass is over (around 2 to 3 in the afternoon). Every Wednesday and Friday are days of fasting because Wednesday is the day that the Lord was condemned and Friday is the day he was crucified (the Wednesdays and Fridays between Easter Sunday and Pentecost Sunday are an exception as well as when Christmas or Epiphany fall on a Wednesday or a Friday). The fasts that are ordained in the canon of the Church of Ethiopia are:
A systematic review of 40 studies found that intermittent fasting was effective for weight loss, with a typical loss of 7-11 pounds over 10 weeks.  There was much variability in the studies, ranging in size from 4 to 334 subjects, and followed from 2 to 104 weeks. It is important to note that different study designs and methods of intermittent fasting were used, and participant characteristics differed (lean vs. obese). Half of the studies were controlled trials comparing the fasting group to a comparison group and/or a control group (either continuous calorie restriction or usual lifestyle), with the other half examining an intermittent fasting group alone. A brief summary of their findings:
Let me assure you at the outset of this book that I am not advocating prolonged periods of fasting for every believer. A fast can be as short as one meal. Neither do I advocate fasting and praying for the mere sake of saying with self-righteousness, "I have fasted and prayed about this." I do not advocate fasting so that the hungry in a foreign nation might have the food you would have eaten that day -- which is highly unlikely. I do not advocate fasting apart from prayer.
DU: The biggest benefit of fasting is disciplining us to focus on God long enough to be changed by Him. I have seen brothers and sisters who, after spending much time in God’s presence through prayer and fasting, have been significantly empowered to carry out God’s call on their lives. From a medical perspective, there are a significant number of credible studies showing that fasting substantially reduces the risk for type 2 diabetes, heart disease, and cancer. I reviewed scientific literature on the health benefits of fasting going back up to 70 years, and what I found is that fasting improves our health span if it is done consistently and intermittently as a lifestyle.
Not only does fasting and prayer help us focus on God, but through that time, it brings us closer to Him and changes our hearts. Niles and Little write, "When we fast and pray, we are taking time away from a meal or an activity to devote our entire being to focus on God. We find we are more sensitive to the voice of God, more attuned to hearing what He has to reveal to us. Gently, God whispers in our mind what we were really thinking at the time of our sin, what our true intent was and we are shocked…momentarily. Then like a light turned on in a pitch black room, we see it. We did mean harm. We were manipulative. Even though our recognition makes us want to hide our face, our loving Savior lifts our chin to look into his forgiving eyes. As we repent, we no longer want to hide, but to praise and worship the very one who confronted our wrong."
Biblical fasting, unlike fasting for medical or health reasons, must be done with an attitude of seriousness and sincerity. When we fast, we willingly deprive the body of nourishment and the pleasurable taste of food. The body requires food for sustenance; therefore our hearts and minds must be totally focused and directed towards God so that He may be the full source of our strength during our period of fasting.
How It Works: This one’s easy: Eat very little one day, and eat like normal the next. On the low-calorie days, that means one fifth of your normal calorie intake. Using 2,000 or 2,500 calories (for women and men, respectively) as a guide, “fasting” (or “down”) day should be 400 to 500 calories. Followers can use this tool to figure out how many calories to consume on “low-calorie” days.
Another type of intermittent fasting, alternate day fasting has you severely restricting the amount of calories you eat during fasting days, then eating to your stomach’s content on non-fasting days. Food isn’t completely off the table, but you’ll stick to about 25 percent of your normal caloric intake. Someone eating 2,000 calories would cut back to 500, for example. Alternate-day fasting isn’t necessarily a long-term plan, because it can become difficult to stick to, but it can be helpful to get a healthy habit in motion.
^ Cléir, Síle de (5 October 2017). Popular Catholicism in 20th-Century Ireland: Locality, Identity and Culture. Bloomsbury Publishing. p. 101. ISBN 9781350020603. Catherine Bell outlines the details of fasting and abstinence in a historical context, stating that the Advent fast was usually less severe than that carried out in Lent, which originally involved just one meal a day, not to be eaten until after sunset.
Once you start your IF journey, you’ll most likely find that you feel fuller longer and can keep the meals you do eat very simple. There are a few different ways you can fast, so I broke up each of the different plans below into beginner, intermediate, and advanced along with a typical meal plan for each day. The combination of nutrients will give you the energy you need to enhance the benefits of your fasting journey. Just make sure to take into account any individual food intolerances, and use this as a guide for your particular health case, and adjust from there.
Intermittent fasting is hard in the contemplation, of that there is no doubt. “You go without food for 24 hours?” people would ask, incredulously when we explained what we were doing. “I could never do that.” But once started, it’s a snap. No worries about what and where to eat for one or two out of the three meals per day. It’s a great liberation. Your food expenditures plummet. And you’re not particularly hungry. … Although it’s tough to overcome the idea of going without food, once you begin the regimen, nothing could be easier.”
What is ghrelin? It is actually also known as the hunger hormone, because it is responsible for telling your body that it is hungry. Dieting and really restrictive eating can actually increase ghrelin production, which will leave you feeling hungrier. But when you fast, though you might struggle in the first few days, you’re actually normalizing ghrelin levels.
Those fasting may experience side effects of fatigue, malaise, aches and pains, emotional duress, acne, headaches, allergies, swelling, vomiting, bad breath, and symptoms of colds and flu. These reactions are sometimes called healing crises, which are caused by temporarily increased levels of toxins in the body due to elimination and cleansing. Lower energy levels should be expected during a fast.
The second major day of fasting is Tisha B'Av, the day approximately 2500 years ago on which the Babylonians destroyed the first Holy Temple in Jerusalem, as well as on which the Romans destroyed the second Holy Temple in Jerusalem about 2000 years ago, and later after the Bar Kokhba revolt when the Jews were banished from Jerusalem, the day of Tisha B'Av was the one allowed exception. Tisha B'Av ends a three-week mourning period beginning with the fast of the 17th of Tammuz. This is also the day when observant Jews remember the many tragedies which have befallen the Jewish people, including the Holocaust.
In the Bahá'í Faith, fasting is observed from sunrise to sunset during the Bahá'í month of 'Ala' ( 1 or 2 March – 19 or 20 March). Bahá'u'lláh established the guidelines in the Kitáb-i-Aqdas. It is the complete abstaining from both food and drink during daylight hours (including abstaining from smoking). Consumption of prescribed medications is not restricted. Observing the fast is an individual obligation and is binding on Bahá'ís between 15 years (considered the age of maturity) and 70 years old. Exceptions to fasting include individuals younger than 15 or older than 70; those suffering illness; women who are pregnant, nursing, or menstruating; travellers who meet specific criteria; individuals whose profession involves heavy labor and those who are very sick, where fasting would be considered dangerous. For those involved in heavy labor, they are advised to eat in private and generally to have simpler or smaller meals than are normal.