Intermittent Fasting (IF) – An effective tool for weight loss with other evident-based health benefits
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Get to know Intermittent Fasting (IF)
Intermittent fasting or IF is defined as an eating pattern that cycles between periods of fasting and feeding conducted on a regular schedule. IF has currently become one of the world’s most popular health and fitness trends as a number of researches reveal that it is an effective way to manage weight and minimize the risk of developing some forms of diseases. Instead of modifying foods, IF rather specifies when you should eat them. In this regard, it is not considered a diet in the conventional sense but more described precisely as an eating pattern that enables you to eat less food with intermittent energy restriction.
Insulin is an essential hormone that helps to regulate the blood sugar (glucose) levels in the body. During digestion, insulin stimulates muscle, fat and liver cells to absorb glucose to be used for energy or converted into fat for long-term storage.
While fasting, the body releases less insulin, allowing the fat cells to release their stored sugar to be used. As a result, reduced insulin levels lower the conversion of glucose into fat, leading to less fat storage under the skin and eventually weight loss. In addition, a decrease in insulin levels can contribute to the elevated levels of growth hormone and norepinephrine, which play critical roles in promoting lipid and energy metabolisms while showing no effects on reducing muscle mass which is a common result of prolonged and continuous fasting.
A variety of IF methods
Involving splitting the day or week into feeding and fasting periods, there are several different ways of doing IF. These are the most popular methods:
- The Leangains or 16/8 IF: The Leangains is a simple and easy form of IF to follow since it is less restrictive and more flexible than many other diets and works with most lifestyles. It involves eating for 8 hours and fasting for 16 hours each day.
- Fast 5: Fast 5 approach consists of 5 hours of eating and 19 consecutive hours of fasting.
- Eat-Stop-Eat: This method involves fasting for 24 hours, once or twice a week, then eating responsibly for the remaining days of the week with appropriate amount of food.
- 5:2 diet: With this method, it involves a 5-day eating and a 2-day fasting, either consecutively or non-consecutively in each week. Rather than eating nothing at all during fasting period, this approach allows you to consume only 600 calories/day for men and 500 calories/day for women, approximately ¼ of daily intake of calories.
- Alternate Day Fasting: This method, considered as an extensive approach, allows you to eat every other day. For example, day 1: eat regular meals, day 2: fast, day 3: eat regular meal, day 4: fast and so on. Similar to those of 5:2 diet, only little calories are allowed on fasting days.
Benefits of IF
IF offers a number of promising health-related benefits if conducted appropriately. Major benefit of IF has been highlighted in weight reduction. Moreover, decreased fat in the body can substantially lead to a risk reduction in a wide range of chronic diseases, such as diabetes, dyslipidemia, hypertension, cardiovascular disease and neurovascular disease. Interestingly, researches show that the intermittent fasting periods do more than burn fat, it helps profoundly to promote the function of the brain while minimizing the risk of Alzheimer’s Disease and delaying cell degeneration process. The medical study published in October, 2017 by The Harvard T.H. Chan School of Public Health, the public health school of Harvard University, reveals that IF can significantly prolong healthy living through inducing “autophagy” – the natural degradation of the cell that removes unnecessary or dysfunctional components in order to regenerate newer and healthier cells. Under normal conditions, when the cells have sufficient nutrients, autophagy degrades damaged components in the cells. When fasting starves the cells, autophagy helps digest some of the cell components to provide the necessary energy for survival, allowing the regeneration of newer cells to replace the damaged ones.
IF conducted along with diet control
Only implementing intermittent fasting alone might not be sufficient to reach desired weight, especially when high-energy food is still being consumed during eating period. More importantly, drawbacks of prolonged fasting may promote over-eating. As the way intermittent fasting is strictly scheduled, many people tend to over-eat on feeding days. On these feasting days, meal size and frequency are not restricted, therefore this may cause some people to eat a lot to compensate for their previous fasting days. Because the body is deprived of food on certain days or between certain hours, the hunger can become extreme which also leads to over-eating. This can also induce excess stress and lack of discipline with reduced physical activity which largely impedes weight loss.
Despite a number of studies have claimed that IF is an effective tool used for losing weight in many people, it does not necessarily mean that it always works for everyone because of the differences in physical conditions and responses among each individual. In addition, some drawbacks of intermittent fasting might be expected. Before starting IF, it is important to check on your physical health and gain sufficient information, including instructions prior to, during and after IF. To reach the optimal benefits, IF should be conducted under close supervision of dieticians and nutrition specialists, ensuring the appropriate technique and the best possible outcomes.
For more information, please contact:
Dietician Department, Weight Management and Obesity Clinic, Bangkok Hospital.
Tel. +662-310-3000 or 1719 (local calls only)