Learn everything you need to know about intermittent fasting, from how to do it to the science behind this approach.
Intermittent fasting is a dietary approach that involves long periods of fasting followed by short periods of feeding or 24 hours of fasting followed by 24 hours of feeding.
There are several variations of intermittent fasting, the most popular of which is fasting for 16 hours followed by 8 hours of feeding..
The basis of intermittent fasting rests on a few key ideas.
Maximize the time the body spends to oxidize fat.
Minimize the overall insulin load.
There are a number of studies carried out to examine how these claims are proven, or not, and the results have been quite interesting.
Main components of intermittent fasting
As noted above, intermittent fasting is based on prolonged periods of fasting followed by a period of feeding.
Intermittent fasting does not normally have amounts of calories macronutrient proportions, nor does it have a list of good and bad foods to eat.
That is, when it comes to the choice of food, it is not very restrictive.
Period and frequency of meals
Unlike many other plans or diets, intermittent fasting depends almost exclusively on the time and frequency of meals.
As we already know, intermittent fasting usually adopts a 16-hour fasting window, followed by an 8-hour fasting window..
Most people consume 1-2 very large meals during the feeding period, although several small meals can be consumed during this time..
Other fasting approaches, such as alternative daytime fasting, employ a 24-hour fast, followed by a full 24-hour diet.
Restrictions and limitations
In addition to time restrictions and limitations, there are no food restrictions. This is often interpreted as anything goes during the feeding period.
However, in practice, people who achieve the best results using intermittent fasting, usually apply another food structure (such as IIFYM or flexible diet) to give them some structure to their food intake during the feeding period..
Are there different phases?
Intermittent fasting does not include any phases in their dietary protocol, although some people go through fasting cycles in which they spend long periods of adherence to the fasting protocols and then periods of normal eating.
Who is this approach best suited to?
Intermittent fasting is more suitable for people who have busy hours and prefer to eat 1-2 meals a day instead of spreading them throughout the day.
Fasting can also be great for people who are learning new, and better, eating habits.
Intermittent fasting is also an excellent way to help people control calories, as often reducing the time you eat during the day can reduce calories overall.
How easy is it to follow?
Intermittent fasting is easy to follow because it does not limit or restrict food, allows you to eat without following calories, and does not put an obstacle in your social life (not being able to go out to dinner and order something from the menu).
It can also make life a lot easier, as less time is spent cooking, eating and cleaning.
It can be difficult for some people who enjoy the process of cooking and eating, as well as having their initial difficulties in controlling hunger due to long periods without eating..
Scientific Studies and Data Interpretation
There are several studies that delve into the benefits of intermittent fasting as a tool to promote fat loss.
The ideal of fasting to promote health benefits has existed since ancient civilization.
Today, many of the speculations about the general health benefits of fasting are still a reason for debate, the big question being whether their origin is mainly in caloric deficit or fasting itself..
Below, we will outline some of the studies that have been conducted and that present these benefits on an impartial platform.
Fat Loss Benefits
One of the biggest claims of intermittent fasting is that it is an excellent tool for fat loss.
There have been several studies that have examined the role of meal frequency in fat loss, including things like alternating daily fasting and even the intermittent fasting protocol.
For a long time these studies were eliminated by social networks and fitness forums, since they were not true studies on the specific protocol of intermittent fasting; however, a study was recently carried out that followed the traditional fasting protocol 16/8, as prescribed by the traditional intermittent fasting protocols (1).
In this study, the group that followed the intermittent fasting protocol lost about 1.5 kg more fat than the group on the normal diet; however, this also occurred simultaneously with a lower caloric intake than the normal diet group, so it is likely that the greatest fat loss was due to a lower caloric intake.
However, the most curious data is not the amount of fat lost.
One of the most interesting notes about this study, as mentioned by Greg Nuckols is that, “Testosterone and IGF-1 levels decreased, levels of various pro-inflammatory cytokines decreased, cortisol levels increased, insulin and glucose levels in the blood decreased, triglyceride levels decreased, T3 levels decreased and RER decreased slightly.
These are all expected data on a low-calorie diet, however, although the intermittent fasting group was in caloric deficit, it was very low (less than 10% below the maintenance value), which was probably not a sufficient deficit to justify these effects..
Overall, this study makes it appear that intermittent fasting deceives your body into thinking you are on a diet, even if it is (or at least close to) caloric maintenance, in a manner generally consistent with improving health and longevity " (two).
Benefits in increasing muscle mass
When looking at the fasting literature, it appears that intermittent fasting does not appear to bring any additional benefits to muscle building when the calories are kept equal.
That said, periods of fasting can improve the quality of muscle tissue, increasing its cell cleaning processes (for example, autophagy and response to heat shock protein) (3,4,5).
However, this research is currently preliminary and is mainly speculation at the moment.
General Health Benefits
Of all the areas of research on fasting, the effects on general health and longevity are perhaps the most interesting.
Several studies in animal models have shown that fasting periods increase life expectancy and improve several metabolic parameters as these animals age (6,7).
Perhaps the most well-known phenomenon of fasting is the increase in autophagy, a process of cellular cleansing.
There is some evidence in animal studies that also suggest that fasting can increase longevity; however, human data are short-term, and long-term evidence is not yet concrete, so much of this is still speculation (8).
Intermittent fasting offers a flexible dietary approach to the diet and may have some unique metabolic benefits for health and longevity.
From a fat loss perspective, intermittent fasting can be an excellent tool, mainly due to controlling calorie intake.
Intermittent fasting can be used in its widely known format of a 16-hour fast followed by an 8-hour feeding period; alternate daily fasting comes close to a 24-hour fast followed by a 24-hour diet.
Intermittent fasting is easy to follow because it does not limit or restrict food, allows you to eat without following tight calories.
Have you tried this food approach? Leave your opinion in the comments!
1) Effects of eight weeks of time-restricted feeding (16/8) on basal metabolism, maximal strength, body composition, inflammation, and cardiovascular risk factors in resistance-trained males. two) The “Leangains” Intermittent Fasting Study Is Finally Here. 3) AMPK Activation of Muscle Autophagy Prevents Fasting-Induced Hypoglycemia and Myopathy during Aging. 4) Autophagy is required to maintain muscle mass. 5) Long-Term Calorie Restriction Enhances Cellular Quality-Control Processes in Human Skeletal Muscle. 6) Apparent Prolongation of the Life Span of Rats by Intermittent Fasting. 7) Fasting: Molecular Mechanisms and Clinical Applications. 8) Effect of 6-Month Calorie Restriction on Biomarkers of Longevity, Metabolic Adaptation, and Oxidative Stress in Overweight Individuals A Randomized Controlled Trial.
Adapted from the muscleandstrength.com article