Intermittent Fasting is a diet that has gained a ton of popularity over the past several years. The idea of not eating for sustained periods of time every day may seem extreme to anyone first hearing about IF. So, what exactly is IF and why is it so popular?
What is intermittent fasting?
IF is actually more of an eating pattern than a diet. The person dieting goes through a long period of fasting throughout the day followed by a small window of time when he/she is allowed to eat. IF focuses on the amount of time one spends eating rather than the volume/type of food. Fasting for a certain number of hours each day or eating just one meal a couple days a week, can help the body burn fat. And scientific evidence points to some health benefits, as well.
Here is a list of three of the most popular methods of fasting.
The 16/8 method: involves skipping breakfast and restricting your daily eating period to 8 hours, such as 1–9 p.m. Then you fast for 16 hours in between.
Eat-Stop-Eat: This involves fasting for 24 hours, once or twice per week. For example, this can be done by not eating from dinner one day until dinner the next day.
The 5:2 Diet: This method involves consuming only 500–600 calories on two nonconsecutive days per week, and eating normally for the remaining 5 days.
What are the pros?
Increase of Human Growth Hormone: The body’s levels of growth hormone increase exponentially which aids in fat loss and muscle growth.
Decrease in Insulin Levels: Insulin sensitivity improves and levels of insulin drop dramatically. These lower insulin levels make fat stored in the body more accessible.
Cellular Repair: When fasted, cells initiate cellular repair processes. This includes autophagy; during which cells digest and remove old and dysfunctional proteins that build up inside of cells.
Gene Expression: These are changes in the function of genes related to longevity and protection against disease.
Reductions in inflammation: Some studies show a reduction in markers of inflammation; a key driver of many chronic diseases
Great for brain health: Studies show the production of the brain hormone BDNF increases and may aid the growth of new nerve cells. It may also protect against Alzheimer’s disease
Less muscle loss when losing weight: IF causes less muscle loss than the more standard method of continuous calorie restriction/calorie deficit.
Increase of fat burning hormone norepinephrine (noradrenaline): Because of these changes in hormones, short-term fasting may increase your metabolic rate by 3.6–14%
IF is a very powerful weight loss tool: By making one eat less frequently, calorie intake is often automatically reduced, making the achievement of the daily calorie deficit needed to lose fat much more attainable. A 2014 review study found that this eating pattern can cause 3–8% weight loss over 3–24 weeks.
IF works GREAT with a busy schedule: Don't have time to break your fast in the morning? Not much of a breakfast person? Don’t have time to eat until lunch/dinner? Do you like black coffee in the morning to keep you going? NO PROBLEM! (p.s. Black coffee, no cream or sugar helps curb appetite. Just make sure you have water first!)
IF does not restrict the type of food eaten or the volume of food taken in: This means you don't necessarily have to cut carbs/fats/sugar from your diet. IF simply states the amount of time per day a person is allowed to take in food. (in hours/days)
While the volume/type of macros eaten are still important for weight loss, the short window of time one is allowed to eat makes overeating throughout the day a more difficult task, making the need to count calories or macros less pertinent. In layman's terms, IF allows the body more time to digest and process food throughout the day and therefore the body is able to remove more toxins.
When fasting, the body is able to change on a cellular and molecular level. For example; human growth hormone levels increase and insulin levels decrease, allowing stored fat in the body to be easily accessed for fat loss and muscle gain. The body’s cells also change the expression of genes and initiate important cellular repair processes.
What are the cons?
Intermittent fasting can be mentally & physically taxing for some: People often fail at IF simply because it can be too uncomfortable for them to fast for long periods of time. Although dieting for fat loss is difficult, it should also be sustainable and enjoyable for the individual, or they will fail to execute the diet with consistency and the results won’t follow.
Intermittent fasting is certainly not for everyone: People bulking or eating several thousands of calories per day (calorie surplus), or even maintaining weight (break even), may find it difficult to sustain IF. For example, it can be very difficult to eat 3000 calories in a period of 6 hours per day and not feel sick.
Women should be careful with IF: Though human studies on this topic are unavailable, studies in rats have found that IF improved insulin sensitivity in men, but worsened blood sugar control with women. The study found that IF made some female rats emaciated, masculinized, infertile and caused them to miss cycles.
IF may be dangerous for people who have issues with infertility, history of eating disorders, are pregnant, or breastfeeding.
Is intermittent fasting right for me?
There is some good scientific evidence suggesting that fasting, when combined with a healthy diet and lifestyle, can be a particularly effective approach to fat loss, especially for people at risk for diabetes. However, people with advanced diabetes or who are on medications for diabetes, people with a history of eating disorders like anorexia and bulimia, people who cannot sustain the diet due to needed calorie intake (bulkers/ people with high Basal Metabolic Rates), and pregnant or breastfeeding women should not attempt intermittent fasting unless under the close supervision of a physician who can monitor them.
Author: Dominique Nevarez