Ruminations on Intermittent Fasting....
First of all, what is Intermittent Fasting (I.F.)?
Practitioners of I.F. restrict their daily caloric intake to a smaller window- typically a 16/8 window, where you are not eating 16 hours out of the day (including sleep time) and you are getting all your calories within an 8 hour “window”. There are also other types of I.F., including the crescendo method that is reportedly more feasible for women, where you practice a 12/12 or 16/8 type of window, but only every other day. And then there is at the 5:2 method, where you eat “regularly” 5 days out of 7, and severely restrict calories the other two days.
This is a loaded topic and there are people who swear by the practice and others who do not find it beneficial at all.
Why I.F. does work for some…..
Simply put, given less time to eat food you are probably going to eat less food and therefore naturally reduce your overall caloric load. There is something thrilling about the hardship too, because feeling hungry also plumbs into deep primal feelings we are often shielded from in our modern lives of plenty here in the first world. Advocates claim that it mimics the eating patterns of our ancient ancestors, who, by all accounts, were healthier even though their life spans were greatly diminished by predators, famine, childbirth, and untreated infections and disease.
Much of the information out there regarding IF is anecdotal, but there is evidence that it works can be an effective tool for males looking to decrease body fat without losing muscle mass. It is a popular weight manipulation tool in the bodybuilding world. For females and performance based athletes, however it could potentially be problematic.
Why it can be counterproductive for females…..
Women’s bodies are exceptionally sensitive to stress and guess what? Starvation (or at least the temporary illusion of starvation) IS A STRESSOR! And when our bodies are stressed, production of ghrelin, cortisol and Neuropeptide Y (NPY) is increased .
Ghrelin is also known as the “hunger hormone”. Go too long without eating and yup, production of this little cutie is going to increase. The word hangry comes from somewhere - thanks ghrelin! We think it’s unwise to get to a point where “hangry” takes over and common sense as well as conscious, well-thought out food choices go out the window.
Cortisol is an adorable little hormone otherwise known as the stress hormone. Women can be especially vulnerable to its siren song. Food deprivation and starvation in the body are interpreted as stress. You can do the math here.
Neuropeptide Y (NPY) is a hormone produced by cells in the brain and nervous system. It is a powerful stimulant for appetite and is highest during periods of fasting or food deprivation. Go back and read “periods of fasting”…..again, call us nut jobs, but we think it’s prudent to try and keep this fun hormone at lower levels.
A fasted body will also see increased levels of Human Growth Hormone and Norepinephrine, a hormone that mobilizes the brain and body to be ready for action. Now these in themselves can be very positive- HGH helps us regulate metabolic functions and Norepinephrine stimulates arousal (aka fight or flight) which is why some people report feeling more mentally focused and clear while in a fasted state. However, we feel that the increases in the other hormones and their potentially negative effects outweigh the positives here for females. We can also increase our HGH levels by lifting heavy weights— a much more pleasurable pursuit in our minds, than being hungry.
Nonetheless, if you are female and still want to give it a go, then know the following symptoms are signs it may not be working for you:
increased irritability
dizziness/feeling faint
unusual and or persistent cravings for refined carbohydrates or junk foods
changes to your menstrual cycle or skipped periods, or inter-menstrual spotting or bleeding
Why it may not be a great idea for athletes (females or male)…
Performance based athletes have caloric loads that sometimes supersede their biological need or desire for food. Remember Michael Phelps and his crazy 6K calories /day diet in 2000? Can you imagine his trying to fit that in in an 8 hour window? Also, carbohydrate and protein timing can become difficult to implement when all your food needs to be consumed in a shorter amount of time. We also know that under-fueling (ie not eating enough) puts them at risk for injury and illness.
The thought of asking our athletes to go into a workout fasted is generally unimaginable to us. We actually would like to see people getting to their workouts with some glycogen in reserve. Glycogen is the stage unit for glucose and is easily mobilized by the body for use, and it is easily accessed by the body when needed. After a workout, we like to see people replenishing this store once again and adding some protein to the mix for muscle repair and recovery.. Talk to your nutrition coach about the optimal workout “sandwich” for your particular pursuits. (Need a nutrition coach?- click here!)
TAKEAWAYS…
If you are male, and looking to incorporate something else, and not currently competing in a sport, try adopting I.F. into your routine and see if it makes you feel better or even ignites weight/and or loss in times of plateau, if you are looking to cut or lean out.
If you are female, or a competitive athlete, we do not recommend adopting IF into your routine at this time.