Intermittent fasting refers to a diet schedule that cycles between not eating and eating. Cycles of intermittent fasting can be hourly or daily.
People may choose to fast for reasons such as religion, diet, or potential health benefits.
During intermittent fasting (IF), people may wish to continue or begin exercising. It is possible to exercise while fasting, but precautions are necessary.
In this article, we explore exercising while fasting, different types of IF, how to plan workouts during fasting, and safety tips to consider.
People who are fasting can partake in exercise. Some people exercise while IF as they believe it has potential health benefits. These include:
When people eat carbohydrates, the body converts this into a type of sugar known as glucose. The body stores glucose as glycogen.
Research suggests that during periods of fasting, glycogen stores are empty. This means the body starts to burn fat for energy during exercise, which may help weight loss.
One study found that exercising in a fasted state also led to a higher fat loss than in people exercising after a meal.
However, other studies have produced different results.
A 2014 study found that people who fasted overnight and exercised did not lose more weight than people who ate before exercise. Another study in mice concluded that IF with or without exercising led to effective weight loss in mice.
To lose weight, the calories someone consumes must be less than those they burn each day. IF may help a person lose weight as it controls the number of calories they eat.
A study that compared IF with a calorie restricted diet that does not include periods of fasting found no major differences in the amount of weight each group lost.
Findings from a review of research looking at exercise and fasting highlight that it may increase autophagy.
Autophagy is a process that helps destroy unwanted or damaged cells to regenerate newer and healthier ones.
A 2018 study found that IF and exercise may slow down aging and disease processes. This is because IF and exercise may cause changes in metabolism.
Research has also identified some potentially negative side effects to exercise while fasting. These can include
The research examining fasting and exercise seems to have conflicting information. Depending on a persons exercise goals, they may want to try IF for fat loss. However, if someone wants to build muscle, they may wish to use alternative diets.
There are a number of different types of intermittent fasting. These include:
If people want to change their usual eating habits, it is worth discussing this with a doctor or nutritionist, especially for a change such as fasting.
It is important to plan workouts during IF to stay safe. Some considerations are:
Which type of exercise a person does will likely depend on the type of fast they do. For example, a person doing 16:8 or nightly fasts can do either aerobic or anaerobic exercise during their periods of eating.
However, if someone is doing alternate days and wants to exercise during their day of not eating, they should probably stick to less intense aerobic exercise.
Pre-workout nutrition should consist of a meal 23 hours before exercise rather than just before. It can be rich in complex carbohydrates, such as whole grain cereal and protein.
A post-workout meal should consist of carbohydrates, high quality proteins, and fats to help recovery.
After planning the workout, it is also worth considering the following tips to stay safe.
For some people fasting and exercising may be more dangerous, including:
If a person has underlying health conditions but wishes to try IF and exercise, it is best they discuss this with their doctor.
People may fast for a variety of reasons, such a religion, diet, or other potential health benefits. It is possible to exercise during IF safely.
Although IF and exercise may help weight loss, there is conflicting evidence saying whether it is more effective than other means, such as calorie restricted eating.
Possible benefits to fasting and exercise are an improvement in the autophagy process and possible anti-aging effects.
However, people may not be able to build muscle during IF and may find they perform poorer in their workouts. A person may want to consider another diet if they wish to build muscle
There are many types of IF. Whichever a person chooses to do, they should plan the workout accordingly and consider potential safety measures.
Excerpt from:
Intermittent fasting and exercise: How to do it safely - Medical News Today
