There are different types of intermittent fasting:
This diet involves restricting your eating to certain periods of the day. Outside of that window, the aim is to consume only zero calorie drinks (i.e. water, black coffee/tea). There is no need to count calories, provided you adhere to the eating timeframe (aim for 4 to 10 hours each day). It is simple and allows for a daily routine to develop.
This diet alternates between a day of feasting and a day of complete abstinence with only water (zero calories). A modified version of the fasting day is restricting your food intake to around 25% of what you would usually eat (around 500 to 800 calories). The attraction of this diet is the lack of restrictions on each alternate feast day. There is no need to count your calories, alongside the freedom to enjoy brunch or dinner with family or friends.
This diet modifies the alternate-day fast with 5 feast days and 2 fast days per week. A reduced calorie count to 25% of your regular calorie count is generally consumed on fasting days. These fasting days can be side by side or separated in between feast days.
When our bodies go without food for a prolonged length of time (i.e. 12 hours or more), production of insulin drops as more glucagon is produced. In turn, this increases the number of long chain fatty acids circulating in the blood, which the liver then uses to produce ketones (insert link to article about ketosis and ketones). This alternative process creates energy when glucose is lacking or absent due to little or no food intake. When adopting an intermittent fasting diet, the fasting period prompts the body to burn fat reserves because it is not getting the energy it normally would get from food.
?All these variations of intermittent fasting still require commitment/habit forming to obtain the benefits such as weight loss. The degree of weight loss is also determined by adherence to the intermittent fasting routine over 12 weeks. Shorter-term adherence results in less weight loss, compared with 12 weeks as an optimal weight loss strategy. Also, a feast day does not mean permission to binge or overeat. Instead, exercise self-control to experience the full benefits of intermittent fasting.
In addition to weight loss, studies show that intermittent fasting decreases the risk of developing some chronic illnesses. The physiological outcomes of fasting include ketogenesis, improving the biological circadian rhythm, reduced blood pressure, reduced insulin production, and decreased insulin resistance. This lowers the risk of hypertension, diabetes, and cardiovascular disease. In addition, the alternate-day fasting and 5:2 diets reduce levels of low-density lipoprotein (LDL) cholesterol and triglycerides. Time-restricted intermittent fasting decreases oxidative stress often present in cancer, diabetes, or neurological disorders. Overall, alternating periods of eating with periods of fasting allows the body to return to a state of balance (homeostasis), leading to better health and wellness.
As with anything, consider the risks before adopting intermittent fasting as a diet or lifestyle choice. Daily fibre intake needs to be managed to ensure you are getting sufficient fibre intake for optimal bowel health. Intermittent fasting is not recommended for those with a low BMI (i.e. less than 18.5), or those who struggle with psychological eating disorders. It is not recommended for women who are pregnant, breastfeeding, or lactating. Lastly, if you are on medications that are required to be taken with food, consider whether intermittent fasting is appropriate. Be sure to seek advice from your general practitioner or another health professional to ensure that intermittent fasting is right for you.
