The concept of intermittent fasting is a relatively new one. Intermittent fasting devotees advocate reducing the amount of time spent feeding and incorporating long fasts to enhance fat loss and body composition. IF’ers will vary in the way they practice fasting with some not eating for over 24 hours at a time and then binging during the short period of time they are able to eat. One of the more popular protocols was devised by Martin Berkhan who advocates a system of eating all your daily calories during an 8 hour feast and then spending the remaining 16 hours of the day fasting. Berkhan claims that by doing this your body will enhance fat loss and improve body composition by taking advantage of hormones which accelerate fat loss during the extended fast and then benefitting from improve nutrient partitioning in the short feeding period.
A new research study (1) has now provided some support for Berkhan’s theory. Researchers provided mice a high fat diet and offered them the option of either eating ad libitum (meaning at will) or constrained their eating hours to just 8 hours which happens to be identical to Berkhan’s recommendations. The mice who were restricted to eating for just 8 hours per day consumed an equivalent number of calories as mice who were provided ad libitum access, however, they were protected against obesity, hyperinsulinemia, hepatic steatosis, inflammation and had improved motor function. The researchers determined that the use of the intermittent fasting style led to improvements across a whole array of cellular signals related to body composition such as mTOR and AMPK pathways. It was these improvements in signals which determine fat loss and muscle gain that allowed the mice who followed the intermittent fasting style protocol to benefit from enhanced nutrient partitioning which means for a given number of calories they were more likely to be directed to muscle cells rather than fat cells.
[h=3][/h][h=3]Our Comments[/h]This study lends powerful evidence supporting the theory of intermittent fasting adding to other research conducted showing that fasting can improve health function or enhance fat loss. The fact that the mice in this study also experienced improvements in liver pathology and glucose dispersal while experiencing reduced leptin resistance lends additional support for fasting being beneficial for both health and bodybuilding.
The researchers explained the superiority of fasting as being linked to a mismatch between our eating schedules and the efficiency with which our organs work. In the past the argument has been made that intermittent fasting is adaptive from an evolutionary perspective as it allows hunger to be suppressed during the AM which would be useful for our ancestors who had to get up and find or hunt their food. Being ravenously hungry first thing in the morning without ready access to food would be bad for our caveman ancestors who did not have access to the latest breakfast cereal to get them going for the day.
Lead researcher Satchidananda Panda explained that each organ has a limited time at which it is efficient and the rest of the day they are more or less inactive. By eating constantly through the day the problem arises that normal metabolic cycles are disrupted so that genes which trigger cycles leading to food breakdown and storage but which are otherwise turned off are never completely on or off.
[h=3]Issues with the study[/h]There are a number of problems with the research which should give people some pause before interpreting it literally in their own lives. First of all this study would ideally be replicated in human subjects as using mice is not an adequate proxy for determining the effects of this eating schedule on humans. Using a nocturnal animal to draw inferences for human subjects is questionable (note that the mice who followed an intermittent style fast eat through the night which itself would be dissimilar to how human IF’ers eat.
The fact that the mice were fed a high fat diet consisting of 61% of calories from fat, compared to just 13% in normal rat chow makes it difficult to draw an inference into athletic populations eating a healthy diet. Furthermore, one confound with the study which has not been addressed by some of the mainstream media reporting this study is the fact the mice following the ad libitum eating plan eat throughout the day and night. If the mice eating around the clock were sleeping less, which as we discussed in our article on sleep, can interfere with fat loss, that may have had a part to play in their poorer health and body composition. The negative effects of restricted sleep such as lowered levels of anabolic hormones and elevated levels of stress hormones would certainly lead to a negative effect for sleep deprived mice.
[h=3]Summary[/h]
The study lends some compelling support to the notion of intermittent fasting albeit with the caveats listed above. While intermittent fasting remains a viable approach to fat loss for athletes, it has to be stressed that results will vary and not everyone responds as well to intermittent fasting as each other. For more details see our interview with Borge ***erli. Regardless of this, for those who enjoy intermittent fasting for the convenience and potential body composition benefits this study adds to an increasing body of evidence supporting the benefits of intermittent fasting.
Author: Reggie Johal
Reggie Johal is a former Great Britain American Football player with a background in strength and fitness coaching with articles published in many leading online and print magazines including Muscle and Fitness. Reggie is the founder of Predator Nutrition.
A new research study (1) has now provided some support for Berkhan’s theory. Researchers provided mice a high fat diet and offered them the option of either eating ad libitum (meaning at will) or constrained their eating hours to just 8 hours which happens to be identical to Berkhan’s recommendations. The mice who were restricted to eating for just 8 hours per day consumed an equivalent number of calories as mice who were provided ad libitum access, however, they were protected against obesity, hyperinsulinemia, hepatic steatosis, inflammation and had improved motor function. The researchers determined that the use of the intermittent fasting style led to improvements across a whole array of cellular signals related to body composition such as mTOR and AMPK pathways. It was these improvements in signals which determine fat loss and muscle gain that allowed the mice who followed the intermittent fasting style protocol to benefit from enhanced nutrient partitioning which means for a given number of calories they were more likely to be directed to muscle cells rather than fat cells.
[h=3][/h][h=3]Our Comments[/h]This study lends powerful evidence supporting the theory of intermittent fasting adding to other research conducted showing that fasting can improve health function or enhance fat loss. The fact that the mice in this study also experienced improvements in liver pathology and glucose dispersal while experiencing reduced leptin resistance lends additional support for fasting being beneficial for both health and bodybuilding.
The researchers explained the superiority of fasting as being linked to a mismatch between our eating schedules and the efficiency with which our organs work. In the past the argument has been made that intermittent fasting is adaptive from an evolutionary perspective as it allows hunger to be suppressed during the AM which would be useful for our ancestors who had to get up and find or hunt their food. Being ravenously hungry first thing in the morning without ready access to food would be bad for our caveman ancestors who did not have access to the latest breakfast cereal to get them going for the day.
Lead researcher Satchidananda Panda explained that each organ has a limited time at which it is efficient and the rest of the day they are more or less inactive. By eating constantly through the day the problem arises that normal metabolic cycles are disrupted so that genes which trigger cycles leading to food breakdown and storage but which are otherwise turned off are never completely on or off.
[h=3]Issues with the study[/h]There are a number of problems with the research which should give people some pause before interpreting it literally in their own lives. First of all this study would ideally be replicated in human subjects as using mice is not an adequate proxy for determining the effects of this eating schedule on humans. Using a nocturnal animal to draw inferences for human subjects is questionable (note that the mice who followed an intermittent style fast eat through the night which itself would be dissimilar to how human IF’ers eat.
The fact that the mice were fed a high fat diet consisting of 61% of calories from fat, compared to just 13% in normal rat chow makes it difficult to draw an inference into athletic populations eating a healthy diet. Furthermore, one confound with the study which has not been addressed by some of the mainstream media reporting this study is the fact the mice following the ad libitum eating plan eat throughout the day and night. If the mice eating around the clock were sleeping less, which as we discussed in our article on sleep, can interfere with fat loss, that may have had a part to play in their poorer health and body composition. The negative effects of restricted sleep such as lowered levels of anabolic hormones and elevated levels of stress hormones would certainly lead to a negative effect for sleep deprived mice.
[h=3]Summary[/h]
The study lends some compelling support to the notion of intermittent fasting albeit with the caveats listed above. While intermittent fasting remains a viable approach to fat loss for athletes, it has to be stressed that results will vary and not everyone responds as well to intermittent fasting as each other. For more details see our interview with Borge ***erli. Regardless of this, for those who enjoy intermittent fasting for the convenience and potential body composition benefits this study adds to an increasing body of evidence supporting the benefits of intermittent fasting.
Author: Reggie Johal
Reggie Johal is a former Great Britain American Football player with a background in strength and fitness coaching with articles published in many leading online and print magazines including Muscle and Fitness. Reggie is the founder of Predator Nutrition.
