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Fasting: health benefits and risks

Intemittent Fasting Melbourne | PVH Fitness

Intermittent Fasting

When people talk about fasting, they commonly associate it with the month of Ramadan. Billions of Muslims engage in this declaration of faith every year. It involves abstaining from food and drink from dawn until dusk. While fasting for Ramadan is a spiritual practice, many people now choose to fast with the belief that there is benefit to our health, not just our souls.

There have been many studies recently that have suggested that intermittent fasting can be good for us. Intermittent fasting means that you abstain from or reduce food and drink intake for a period of time. Anywhere between 12 hours to 2-4 days.

One of the most well-known intermittent fasting diets is 5:2 Diet. This involves eating your recommended calorie intake for 5 days a week but reducing calorie intake to 25% for the other 2 days. Around 600 calories for men and to 500 calories for women.

The author of the Book "The Fast Diet", Dr. Michael Mosley, promotes the 5:2 diet. In the book he talks about how eating this way can offer many more benefits other than just weight loss. "Studies of intermittent fasting show that not only do people see improvements in blood pressure and their cholesterol levels, but also in their insulin sensitivity," says Dr. Mosley.

A Study conducted by Dr. Valter Longo and colleagues from the University of Southern California, found that longer periods of fasting (around 2 to 4 days) may even reboot the immune system. It does this by clearing out old immune cells and regenerate new ones. A process they say could protect against cell damage.

So, what are some of the potential benefits from intermittent fasting?

8 hours after eating your last meal the body is unable to get energy from the food anymore. It starts by using glucose that is being stored in the liver and muscles. When the glucose is used up, the body starts to convert body fat into fatty acids, which are easily absorbed into the blood. Fatty acids produce molecules called ketones, which the body uses as a fuel source.

Dr. Razeen Mahroof, of University of Oxford in UK, says that a body using ketones for energy helps preserve muscle and reduce cholesterol levels. "A Detoxification process also occurs, because any toxins stored in the body's fat are dissolved and removed from the body." He also adds that after a few days of fasting, the body release endorphins into the blood, which has a positive impact on the mental well-being.

Dr. Longo's Study also suggests that prolonged fasting may be effective for regenerating immune cells. "When you starve, the system tries to save energy, and one of the things it can do to save energy is to recycle a lot of immune cells that are not needed, especially those that may be damaged," Dr. Longo Explains. In the study, cancer patients who fasted 3 days prior to chemo treatments were protected against immune system damage that is caused by the treatment. "If you start with a system heavily damaged by chemotherapy or aging, fasting cycles can generate, literally, a new immune system."

With all these benefits, what are the risks?

  • Dehydration. We get a lot of our water intake from food. 
  • Increased stress levels.
  • Disrupted sleep from feeling hungry.
  • Heartburn. The lack of food can reduce stomach acid but smelling food while fasting can trigger the brain to release more acid.
  • All of the above can lead to headaches.

Some health professionals believe intermittent fasting may steer people away from healthy eating recommendations. They believe eating 5 portions of fruits and vegetables a day is important. Their also caution that fasting may also trigger eating disorders. People could overeat, which creates guilt, shame, and other problems that can become a cycle, amplify these issues.

Who should not do intermittent fasting?

  • People with type 1 diabetes.
  • Someone recovering from surgery.
  • Pregnant or breast feeding.
  • People who are already underweight.
  • Anyone under the age of 18 years.
  • Have an eating disorder.
  • Anyone with heart problems.
  • Uncontrolled migraines.
  • Undergoing a blood transfusion.
  • If you are taking specific medication

It always best to consult your doctor before starting a diet like this and consider undertaking a fast under supervision.

Author: Mark Boddington

Mark is the Senior Coach at PVH Fitness