Intermittent fasting (IF) refers to dietary eating patterns that involve not eating or severely restricting calories for an extended period of time. There are many different subgroups of intermittent fasting, each with an individual variation in the length of the fast; some by the hour, some by the day (s). This has become an extremely popular topic in the scientific community due to all the potential health and fitness benefits that are being discovered.
WHAT IS INTERMITTENT FASTING (IF)?
Fasting or periods of voluntary abstinence from food have been practiced throughout the world for centuries. Intermittent fasting with the goal of improving health relatively new. Intermittent fasting involves restricting your food intake for a set period of time and does not include any changes to the actual foods you are eating. Currently, the most common IF protocols are the daily 16-hour fast and fasting for an entire day, one or two days a week. Intermittent fasting could be considered a natural eating pattern that humans are built to implement and dates back to our Paleolithic hunter-gatherer ancestors. The current model of a planned intermittent fasting program could help improve many aspects of health, from body composition to longevity to aging. Although IF goes against the norms of our culture and common daily routine, science may be pointing to a lower meal frequency and longer fasting time as the optimal alternative to the normal breakfast, lunch and dinner pattern. Here are two common myths related to intermittent fasting.
Myth 1 – You should eat 3 meals a day: This “rule” that is common in western society was not developed based on evidence of better health, but was adopted as the common pattern for settlers and eventually became the rule. Not only is there a lack of scientific foundation in the 3 meals a day model, recent studies may be showing that fewer meals and more fasting are optimal for human health. One study showed that one meal a day with the same amount of calories per day is better for weight loss and body composition than three meals a day. This finding is a basic concept that extrapolates to intermittent fasting and those who choose to do SI may find that it is 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 need for a daily breakfast. The most common claims are “breakfast increases your metabolism” and “breakfast decreases your food intake later in the day.” These claims have been disproven and studied over a 16-week period with results showing that skipping breakfast did not decrease metabolism and did not increase food intake at lunch and dinner. It’s still possible to do intermittent fasting protocols while eating breakfast, but some people find it easier to eat late breakfast or skip it altogether and this common myth shouldn’t get in the way.
TYPES OF INTERMITTENT FASTING:
Intermittent fasting comes in a number of forms, and each can have a specific set of unique benefits. Each form of intermittent fasting has variations in the ratio of fasting to food. The benefits and effectiveness of these different protocols may differ on an individual basis and it is important to determine which one 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. ALTERNATIVE FASTING:
This approach involves alternating calorie-free days (from food or drink) with days of free feeding and eating whatever you want.
This plan has been shown to aid weight loss, improve blood cholesterol and triglyceride (fat) levels, and improve blood markers of inflammation.
The main disadvantage of this form of intermittent fasting is that it is the most difficult to maintain due to the hunger reported during the fasting days.
2. MODIFIED FASTING – DIET 5: 2
Modified fasting is a protocol with scheduled fasting days, but fasting days allow for some food intake. Generally, it is allowed to consume between 20 and 25% of the normal calories in the days of fasting; therefore, if you normally consume 2,000 calories on regular feeding days, you will be allowed between 400 and 500 calories on fasting days. The 5: 2 part of this diet refers to the ratio of non-fasting days to fasting days. So on this regimen, I would eat normally for 5 consecutive days, then fast or restrict calories to 20-25% for 2 consecutive days.
This protocol is great for weight loss, body composition, and may also benefit blood sugar regulation, lipids, and inflammation. Studies have shown that the 5: 2 protocol is effective for weight loss, improves / reduces markers of inflammation in the blood (3), and shows signs of improvements in insulin resistance. In animal studies, this modified 5: 2 fasting diet resulted in decreased fat, decreased hunger hormones (leptin), and increased levels of a protein responsible for improvements in fat burning and regulating blood sugar (adiponectin).
The modified 5: 2 fasting protocol is easy to follow and has a small number of negative side effects including hunger, low energy, and some irritability when starting the program. However, contrary to this, studies have also noted improvements such as reduced tension, less anger, less fatigue, improvements in self-confidence, and a more positive mood.
3. TIME RESTRICTED FEEDING:
If you know someone who has said they are doing intermittent fasting, it is most likely in the form of time-restricted eating. This is a type of intermittent fasting that is used on a daily basis and involves consuming only calories for a small part of the day and fasting for the rest. Daily fasting intervals on time-restricted eating can range from 12 to 20 hours, with the most common method being 16/8 (fasting for 16 hours, consuming calories for 8). For this protocol, the time of day is not important as long as you fast for a consecutive period of time and only eat in the allowed period of time. For example, in a 16/8 time-restricted eating program, one person may eat their first meal at 7 a.m. and last meal at 3 p.m. (fasting from 3 p.m. to 7 a.m.), while another person You can eat your first meal at 1 pm and your last meal at 3 pm 9 pm (fasting from 9 pm to 1 pm). This protocol is meant to be performed every day for long periods of time and is very flexible as long as you stay within the fasting / feeding windows.
Time-restricted eating is one of the easiest intermittent fasting methods to follow. Using this in conjunction with your daily work and sleep schedule can help you achieve optimal metabolic function. Time-restricted eating is a great program to follow for losing weight and improving body composition, as well as for some other general health benefits. The few human trials that were conducted saw significant reductions in weight, reductions in fasting blood glucose, and improvements in cholesterol with no change in perceived tension, depression, anger, fatigue, or confusion. Some other preliminary results from animal studies showed time-restricted eating to protect against obesity, high insulin levels, fatty liver disease, and inflammation.
The easy application and promising results of time-restricted eating could possibly 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-meal ratio, such as 12/12 hours, and eventually work your way up to 16/8 hours.
COMMON QUESTION ABOUT INTERMITTENT FASTING:
Are there any foods or drinks that I can consume during intermittent fasting? Unless you are on the modified 5: 2 fasting diet (mentioned above), you should not eat or drink anything that contains calories. You can consume water, black coffee and any food / drink that does not contain calories during a period of fasting. In fact, adequate water intake is essential during FI and some say that drinking black coffee while fasting helps decrease hunger.
IF YOU ONLY WANT THE BENEFITS:
Research on intermittent fasting is in its infancy, but it still has great potential for weight loss and the treatment of some chronic diseases.
In summary, these are the possible benefits of intermittent fasting:
Shown in human studies:
1. Weight loss
2. Improve blood lipid markers such as cholesterol.
3. Reduce inflammation
4. Reduction of stress and improvement of self-confidence
5. Improved mood
It is shown in animal studies:
1. Decrease in body fat
2. Decreased levels of the hunger hormone leptin.
3. Improves insulin levels
4. Protect against obesity, fatty liver disease, and inflammation.