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Intermittent fasting is not a diet. It is a timed approach to eating. Unlike a dietary plan that restricts where calories come from, intermittent fasting does not specify what foods a person should eat or avoid. Intermittent fasting may have some health benefits, including weight loss, but is not suitable for everyone.
Intermittent fasting involves cycling between periods of eating and fasting. At first, people may find it difficult to eat during a short window of time each day or alternate between days of eating and not eating. This article offers tips on the best way to begin fasting, including identifying personal goals, planning meals, and establishing caloric needs.
Intermittent fasting is a popular method that people use to:
- simplify their life
- lose weight
- improve their overall health and well-being, such as minimizing the effects of aging
Though fasting is safe for most healthy, well-nourished people, it may not be appropriate for individuals who have any medical conditions. For those ready to start fasting, the following tips aim to help them make the experience as easy and successful as possible.
Typically, a person who starts intermittent fasting has a goal in mind. It may be to lose weight, improve overall health, or improve metabolic health. A person’s ultimate goal will help them determine the most suitable fasting method and work out how many calories and nutrients they need to consume.
There are four potential methods that a person may try when fasting for health reasons. A person should pick the plan that suits their preferences and which they think they can stick with.
- Eat Stop Eat
- Warrior Diet
- Alternate Day Fasting
Typically, a person should stick with one fasting method for a month or longer to see if it works for them before trying a different method. Anyone who has a medical condition should talk to their healthcare provider before beginning any fasting method.
When deciding on a method, a person should remember that they do not need to eat a certain amount or type of food or avoid foods altogether. A person can eat what they want. However, to reach health and weight loss goals, it is a good idea to follow a healthful, high-fiber, vegetable-rich diet during the eating periods.
Binging on unhealthful foods on eating days can hinder health progress. It is also extremely important to drink lots of water or other no-calorie beverages throughout the fast days.
Eat Stop Eat
Brad Pilon developed Eat Stop Eat, which is a fasting method that involves eating nothing for 24 hours twice a week. It does not matter what days a person fasts or even when they begin. The only restriction is fasting must last for 24 hours and on non-consecutive days.
People who do not eat for 24 hours will likely become very hungry. Eat Stop Eat may not be the best method for people who are unfamiliar with fasting to start with.
Ori Hofmekler is the creator of the Warrior Diet, which entails eating very little for 20 hours each day. A person fasting in this way consumes all their typical food intake in the remaining 4 hours.
Eating a whole day’s worth of food in such a short time can make a person’s stomach quite uncomfortable. This is the most extreme fasting method, and similarly to Eat Stop Eat, a person new to fasting may not want to start with this method.
Martin Berkhan created Leangains for weightlifters, but it has gained popularity among other people who are interested in fasting. Unlike Eat Stop Eat and the Warrior Diet, fasting for Leangains involves much shorter periods.
For example, males who choose the Leangains method will fast for 16 hours and then eat what they want for the remaining 8 hours of the day. Females fast for 14 hours and eat what they want for the remaining 10 hours of the day.
During the fast, a person must avoid eating any food but can drink as many no-calorie beverages as they like.
Alternate Day Fasting, 5:2 method
Some people fast on alternate days to improve blood sugar, cholesterol, and weight loss. A person on the 5:2 method eats 500 to 600 calories on two non-consecutive days each week.
Some alternate-day fasting regimens add in a third day of fasting each week. For the rest of the week, a person eats only the number of calories they burn during the day. Over time, this creates a calorie deficit that allows the person to lose weight.
There are no dietary restrictions when fasting, but this does not mean calories do not count.
People who are looking to lose weight need to create a calorie deficit for themselves — this means that they consume less energy than they use. People who are looking to gain weight need to consume more calories than they use.
There are many tools available to help a person work out their caloric needs and determine how many calories they need to consume each day to either gain or lose weight. A person could also speak to their healthcare provider or dietitian for guidance on how many calories they need.
A person interested in losing or gaining weight may find it helps to plan what they are going to eat during the day or week.
Meal planning does not need to be overly restrictive. It considers calorie intake and incorporating proper nutrients into the diet.
Meal planning offers many benefits, such as helping a person stick to their calorie count, and ensuring they have the necessary food on hand for cooking recipes, quick meals, and snacks.
Not all calories are the same. Although these fasting methods do not set restrictions on how many calories a person should consume when fasting, it is essential to consider the nutritional value of the food.
In general, a person should aim to consume nutrient-dense food, or food with a high number of nutrients per calorie. Though a person may not have to abandon junk food entirely, they should still practice moderation and focus on more healthful options to gain the most benefits.
Fasting has several effects on a person’s body. These effects include:
- Reducing levels of insulin, which makes it easier for the body to use stored fat.
- Lowering blood sugars, blood pressure, and inflammation levels.
- Changing the expression of certain genes, which helps the body protect itself from disease as well as promoting longevity.
- Dramatically increases human growth hormone, or HGH, which helps the body utilize body fat and grow muscle.
- The body activates a healing process doctors call autophagy, which essentially means that the body digests or recycles old or damaged cell components.
Fasting dates back to ancient humans who often went hours or days between meals as obtaining food was difficult. The human body adapted to this style of eating, allowing extended periods to pass between food intake times.
Intermittent fasting recreates this forced-fasting. When a person undertakes an intermittent fast for dietary proposes, it can be very effective for weight loss. In fact, according to one study, most people try intermittent fasting to help lose weight.
Other research backs up the claims that fasting can help a person lose weight. For example, a review of studies shows that many people who fast see a higher loss of visceral body fat and a similar to slightly less reduction in body weight compared with people who follow more traditional calorie reduction diets.
For a healthy, well-nourished person, intermittent fasting offers very few side effects.
When a person first starts fasting, they may feel slightly physically and mentally sluggish as their body adjusts. After the adjustment, most people go back to functioning normally.
However, people with medical conditions should consult their doctor before beginning any fasting program. People particularly at risk from fasting and who may require medical supervision include:
- women who are breastfeeding
- women who are pregnant
- people who are trying to conceive
- people with diabetes
- people who have difficulty regulating sugar
- people with low blood pressure
- people on medications
- people with eating disorders
- people who are underweight
For healthy individuals, intermittent fasting should not affect their ability to exercise except during the period when the body is adjusting to the new eating schedule. After the adjustment period, a person should not feel any ill effects from fasting on their exercise routine.
Those worried about losing muscle while fasting should be sure to consume enough protein during eating periods and participate in resistance training regularly. By keeping protein intake up, a person is less likely to lose muscle mass from fasting.
Fasting is a natural part of the human life cycle. Most people have fasted unknowingly throughout their lifetimes by eating an early dinner and skipping breakfast the next day. More structured approaches may work well for some people.
However, it is important to keep in mind that although a person does not need to exclude certain foods from their diet, they should still aim to eat a balanced diet rich in protein, fiber, and vegetables. Remember to drink plenty of fluids, too.
Finally, though the average person will likely experience no or minimal side effects, people with certain medical conditions or who are taking certain medications should speak to their doctor before trying a fasting plan.