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Intermittent Fasting


Intermittent fasting is a dietary approach that involves interspacing planned periods of fasting with regular eating. It is an eating pattern that cycle between periods of eating and    fasting. It focuses more on when to eat rather than what to eat.

Intermittent fasting works by prolonging the period when the body has burned through the calories consumed from the last meal and begins to burn fat. The body will use up its sugar stores and starts to burn fat after hours of fasting, this process is known as metabolic switching.

Benefits of Intermittent Fasting

Help Lose Weight and Visceral Fat

Intermittent fasting can support hormone function to facilitate weight loss. Lower insulin levels, higher Human Growth Hormone (HGH) levels, and increased amounts of noradrenaline can assist in the breakdown of body fat and facilitate its use for energy. Because of this, fasting actually increases the body metabolic rate and eventually help to burn more calories. According to a 2014 review of the scientific literature, intermittent fasting can cause weight loss of 3–8% over 3–24 weeks.

Lowering risk for Type II Diabetes

Intermittent fasting has been shown to have major benefits for insulin resistance, leading to an impressive reduction in blood sugar levels. In human studies on intermittent fasting, fasting blood sugar has been reduced by 3–6% over the course of 8–12 weeks in people with prediabetes. Fasting insulin has been reduced by 20–31%.

Beneficial for Heart Health

Intermittent fasting improves heart health by controlling the risk factors that lead to heart diseases. The risk factors include blood sugar levels, blood pressures, cholesterol levels and inflammatory markers.

Improve Sleep

Research suggests that intermittent fasting may improve sleeping quality by reinforcing the circadian rhythms.

Types of Intermittent Fasting

Time-Restricted Fasting (16/8 method)

The 16/8 method involves choosing of an eating window (about 8 hours) everyday and fast during the remaining 16 hours. It is also known as the Leangains protocol and can be very simple as we only have to skip our breakfast and not eating anything after dinner.

The easiest way to practice 16/8 method is to choose a 16-hours fasting period which include the time we spent sleeping. For example:

  • 9 a.m. to 5 p.m.
  • 10 a.m. to 6 p.m.
  • 12 a.m. to 8 p.m.

Fast Diet (5:2 method)

It involves eating normal diet 5 days a week and restricting the calorie intake to 500 – 600 in the other 2 days. During the fast, the calorie intake is limited to 500 for women and 600 for men respectively.

For example, we may have normal diet every day of the week except Friday and Saturday. For those 2 days, we can eat 2 or 3 small meals with total calories not exceeding the limit.

Eat Stop Eat

Following this method, one has to practice a 24-hours fast once or twice per week. Important tip here is to eat responsibly after the fast. Eating responsibly refers to eating normal diet where we don’t binge because we just fasted, but we also don’t restrict ourselves with an extreme diet (eating more or less than we need).

For example, if we finish our dinner at 7p.m., then the next meal should be on 7.pm. the next day. By this, we have completed a 24-hours fast. Water, coffee, and zero-calories beverages are allowed during this period to help with the fast.

This method may be difficult for many people to follow. However, we can start with 14 hours fast and slowly increase to 24 hours.

Alternate Day Fasting

There are several different versions of this method. Some of them allow 500 calories (about 25% of calorie need) during the fast and eat normally during the non-fasting days. A full fast every other day can be rather extreme and is not recommended to beginners.

Fasting Tips

  1. Drink cinnamon tea during the fast to help suppress the appetite.
  2. Exercise just before or during the eating window.
  3. Meditation during the fasting period to pass the hunger pangs.
  4. Practice balance and healthy diet.
  5. Always check with your primary care provider before starting any restrictive eating plan.

Who Should Avoid Intermittent Fasting

  1. Teenagers under 18 years old.
  2. Pregnant or breastfeeding women.
  3. People with diabetes mellitus.
  4. People with eating disorders such as anorexia.

References

  1. Mosley M, Spencer M. The FastDiet: Lose Weight, Stay Healthy, and Live Longer with the Simple Secret of Intermittent Fasting. Atria Books. 2013
  2. Williams KV, Mullen ML, Kelley DE, Wing RR. The effect of short periods of caloric restriction on weight loss and glycemic control in type 2 diabetes. Diabetes Care. 1998;21:2–8.
  3. Varady KA, Bhutani S, Klempel MC, et al. Alternate day fasting for weight loss in normal weight and overweight subjects: a randomized controlled trial. Nutr J. 2013;12:146.
  4. LeCheminant JD, Christenson E, Bailey BW, Tucker LA. Restricting night-time eating reduces daily energy intake in healthy young men: a short-term cross-over study. Br J Nutr. 2013;110:2108–2113.
  5. Ekmekcioglu C, Touitou Y. Chronobiological aspects of food intake and metabolism and their relevance on energy balance and weight regulation. Obesity Reviews. 2011;12:14– 25.