All about intermittent fasting
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 individual variation in the duration of the fast; some by the hour, others 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 (AI)?
Fasting, or periods of voluntary abstinence from food, has been practiced around the world for centuries. Intermittent fasting with the goal of improving health relatively new. Intermittent fasting is restricting your food intake for a set period of time and does not include any changes to the actual food you are eating. Currently, the most common IF protocols are a 16-hour daily fast and a full-day fast, one or two days per week. Intermittent fasting could be considered a natural eating pattern that humans are designed to implement and dates back to our Paleolithic hunter-gatherer ancestors. The current model of a planned intermittent fasting program could potentially 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 lower meal frequency and longer fasting as the optimal alternative to the normal breakfast-lunch-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 of better health, but was instead adopted as the common pattern for colonists and eventually became the rule. Not only is there a lack of scientific support for the 3 meals a day model, but recent studies may be showing that fewer meals and more fasts 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 3 meals a day. This finding is a basic concept that extrapolates to intermittent fasting, and those who choose to do IF may find it best to eat only 1-2 meals per day.
Myth 2: You need to eat 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 “breakfast increases metabolism” and “breakfast decreases food intake later in the day.” These claims have been refuted 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 without skipping breakfast, but some people find it easier to eat breakfast late or skip it altogether and this common myth shouldn’t get in the way.
TYPES OF INTERMITTENT FASTING:
Intermittent fasting comes in various forms and each can have a specific set of unique benefits. Each form of intermittent fasting has variations in the relationship between fasting and eating. 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. FASTING ON ALTERNATE DAYS:
This approach consists of alternating days without calories (from food or drink) with days of free eating and eating what you want.
This plan has been shown to help with weight loss, improve cholesterol and triglyceride (fat) levels in the blood, and improve markers of inflammation in the blood.
The main disadvantage of this form of intermittent fasting is that it is the most difficult to follow due to the hunger that is reported during the fasting days.
2. MODIFIED FASTING – 5:2 DIET
The modified fast is a protocol with scheduled fasting days, but the fasting days allow for some food intake. In general, 20-25% of normal calories are allowed to be consumed on fasting days; therefore, if you normally consume 2000 calories on regular eating days, you will be allowed 400-500 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, you would eat normally for 5 consecutive days, then fast or restrict calories to 20-25% for 2 consecutive days.
This protocol is excellent for weight loss, body composition, and may also benefit regulation of blood sugar, lipids, and inflammation. Studies have shown the 5:2 protocol to be effective for weight loss, improve/decrease blood markers of inflammation (3), and show signs of improving insulin resistance trends. In animal studies, this modified 5:2 fasting diet resulted in increased fat, increased hunger hormones (leptin), and increased levels of a protein responsible for enhancing fat burning and energy. regulation of 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. Contrary to this, however, studies have also noted improvements such as reduced stress, less anger, less fatigue, improvements in self-confidence, and a more positive mood.
3. FOOD WITH TIME RESTRICTION:
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 only consuming 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 16/8 being the most common method (fasting for 16 hours, consuming calories for 8). For this protocol, the time of day is not important as long as you are fasting for a consecutive period of time and only eat in the allowed period of time. For example, in a time-restricted 16/8 eating schedule, one person may eat their first meal at 7 am and their last meal at 3 pm (fasting from 3 pm to 7 am), while another person you can eat your first meal at 1 p.m. (fast from 9PM-1PM). This protocol is meant to be done every day for long periods of time and is very flexible as long as you stay within the fasting/eating 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 achieve optimal metabolic function. Time-restricted eating is a great program to follow to lose weight and improve body composition, as well as other general health benefits. The few human trials that have been conducted noted significant reductions in weight, reductions in fasting blood glucose, and improvements in cholesterol without changes in perceived stress, depression, anger, fatigue, or confusion. Some other preliminary results from animal studies showed that time-restricted eating protects against obesity, high insulin levels, fatty liver disease, and inflammation.
The easy application and promising results of time-restricted feeding could make it an excellent choice for weight loss and chronic disease prevention/management. When implementing this protocol, it may be helpful to start with a lower fasting to eating ratio, such as 12/12 hours, and eventually work your way up to 16/8 hours.
COMMON QUESTION ABOUT INTERMITTENT FASTING:
Is there any food or drink that I can have during intermittent fasting? Unless you are following the modified 5:2 fasting diet (mentioned above), you should not eat or drink anything that contains calories. Water, black coffee and any food/beverage that does not contain calories can be consumed during a fasting period. In fact, adequate water intake is essential during IF and some say that drinking black coffee on an empty stomach 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. Stress reduction and self-confidence improvement
5. Improved mood
Shown in animal studies:
1. Decrease in body fat
2. Decreased levels of the hunger hormone leptin
3. Improve insulin levels
4. Protects Against Obesity, Fatty Liver Disease, And Inflammation