Intermittent fasting (IF) refers to dietary eating patterns that involve not eating or severely restricting calories for long periods of time. There are several different subgroups of intermittent fasting, each with varying degrees of fasting duration; Some for hours, others for day(s). It has become an extremely popular topic in the science community because of all the potential benefits being discovered on fitness and health.
What is (if) intermittent fasting?
Fasting, or a period of voluntary abstinence from food, has been practiced around the world for centuries. Intermittent fasting with the goal of improving health is relatively new. Intermittent fasting involves restricting food intake for a set period of time and does not involve any change in the actual foods you are eating. Currently, the most common IF protocol is a daily 16-hour fast and fasting throughout the day, one or two days per week. Intermittent fasting can be considered a natural eating pattern that humans were designed to implement and that is similar to that of our Paleolithic hunter-gatherer ancestors. The current model of a planned program of intermittent fasting could potentially help improve many aspects of health, from body composition to longevity and aging. Although if it goes against the norms of our culture and normal daily routine, science may point towards less meal frequency and longer periods of fasting as the optimal alternative to the normal breakfast, lunch and dinner model. Here are two common myths related to intermittent fasting.
Myth 1 – You must eat 3 meals per day: This “rule” that is common in Western society was not developed based on evidence for better health, but was adopted as a general pattern by settlers and eventually became the norm. The model of eating three meals a day not only lacks scientific rationale, but recent studies suggest that eating less and fasting more is best for human health. One study showed that one meal a day with the same amount of daily calories is better for weight loss and body composition than 3 meals per day. This conclusion is a basic concept incorporated into intermittent fasting and those who want to try it may find it best to eat only 1-2 meals per day.
Myth 2 – You need breakfast, it’s the most important meal of the day: Many false claims have been made about the absolute necessity of a daily breakfast. The most common claims are that “eating breakfast boosts your metabolism” and “eating breakfast reduces food intake during the day”. These claims have been refuted and studies over a period of 16 weeks showed that skipping breakfast did not lower metabolism and did not increase food intake at lunch and dinner. It is possible to do an intermittent fasting protocol while still having breakfast, but some people find it easier to delay breakfast or skip it altogether and don’t let this common myth get in the way.
Types of Intermittent Fasting:
Intermittent fasting comes in a variety of forms and each may have a specific set of unique benefits. The fasting-to-eating ratio varies with each form of intermittent fasting. The benefits and effectiveness of these different protocols may vary on an individual basis and it is important to determine which is best for you. Factors that may influence which one to choose include health goals, daily schedule/routine, and current health status. The most common types of IF are alternate-day fasting, time-restricted eating, and modified fasting.
1. Alternate Day Fasting:
This approach alternates days with no calories (from food or drink) with freebies and days of eating whatever you want.
This plan has been shown to help with weight loss, improve blood cholesterol and triglyceride (fat) levels, and improve markers of inflammation in the blood.
The main disadvantage with this form of intermittent fasting is that it is most difficult to maintain due to perceived hunger during fasting days.
2. Modified Fasting – 5:2 Diet
Modified fasting is a protocol with programmed fasting days, but allowing certain food intake on fasting days. Usually 20-25% of normal calories are allowed to be consumed on fasting days; So if you typically consume 2000 calories on regular eating days, you would be allowed 400-500 calories on fasting days. The 5:2 ratio of this diet refers to the ratio of non-fasting and fasting days. So on this diet you will eat normally for 5 days in a row, then fast or restrict calories by 20-25% for 2 days in a row.
This protocol is great for weight loss, body composition, and may also benefit regulation of blood sugar, lipids, and inflammation. Studies have shown that the 5:2 protocol is effective for weight loss, improving/reducing inflammatory markers in the blood (3), and shows signs of improving insulin resistance. In animal studies, this modified fasting 5:2 diet resulted in decreased body fat, decreased hunger hormones (leptin), and increased levels of a protein responsible for burning fat and improving blood sugar regulation (adiponectin).
The modified 5:2 fasting protocol is easy to follow and has few negative side effects including increased appetite, low energy and some irritability when starting the program. On the contrary, however, studies have also shown improvements such as decreased stress, less anger, less fatigue, improved self-confidence, and more positive mood.
3. Time-Restricted Eating:
If you know someone who has said they do intermittent fasting, chances are it’s in the form of time-restricted eating. This is a type of intermittent fasting that is used daily and involves consuming only calories during a small part of the day and fasting for the remainder. Daily fasting intervals in time-restricted diets can range from 12–20 hours, with the most common pattern being 16/8 (fasting for 16 hours, consuming calories for 8). The time of day is not important for this protocol as long as you are fasting for some continuous period of time and only eating within your allowed time periods. For example, one person in a 16/8 time-restricted eating schedule might eat their first meal at 7 a.m. and last meal at 3 p.m. (fast from 3 a.m. to 7 a.m.), while another person might eat their first meal at 1 p.m. and last at 9 p.m. (Fasting from 9 pm to 1 pm). This protocol is meant to be executed over a long period of time every day and is very flexible as long as you are staying within the fasting/eating window(s).
Time-restricted eating is one of the easiest methods of intermittent fasting. Using it along with your daily work and sleep schedule can help achieve optimal metabolic function. Time-restricted eating is a great program for weight loss and improving body composition, as well as some other overall health benefits. The few human trials conducted showed significant reductions in weight, reductions in fasting blood sugar, and improvements in cholesterol, with no change in perceived stress, depression, anger, fatigue, or confusion. Some other preliminary results from animal studies have shown that time-restricted eating has been shown to protect against obesity, high insulin levels, fatty liver disease and inflammation.
The easy application and promising results of time-restricted eating could potentially make it an excellent option for weight loss and chronic disease prevention/management. When implementing this protocol it may be good to start with a lower fasting-to-eating ratio such as 12/12 hours and eventually work up to 16/8 hours.
Common questions about intermittent fasting:
Are there any foods or beverages that I am allowed to consume during intermittent fasting? Unless you’re doing a modified fasting 5:2 diet (mentioned above), you shouldn’t eat or drink anything that contains calories. It is okay to consume water, black coffee and any foods/drinks that do not contain calories during the fasting period. In fact, adequate water intake is essential during IF and some people say that drinking black coffee during fasting helps reduce appetite.
If you only want profit:
Research on intermittent fasting is still in its infancy, but it still holds great potential for weight loss and the treatment of some chronic diseases.
In summary, here are the potential benefits of intermittent fasting:
Human studies have shown:
1. Weight Loss
2. Improve blood lipid markers such as cholesterol
3. Reduce Inflammation
4. Decreased stress and improved self-confidence
5. Improve mood
Animal studies have shown:
1. Decreased body fat
2. Decreased levels of the hunger hormone leptin
3. Improves Insulin Levels
4. Protect Against Obesity, Fatty Liver Disease and Inflammation
5. Longevity
Source by Blake Pennock
