Saturday, February 19, 2011

Intermittent Fasting

According to Wikipedia -"Intermittent Fasting is a pattern of eating that alternates between periods of fasting (usually meaning consumption of water only) and non-fasting.......There is some evidence that intermittent fasting may have beneficial effects on the health and longevity of animals—including humans"

"There have been a few human studies on IF, and all have shown a marked improvement in virtually every parameter tested.....Most fasted until 5 or 6 PM on the fast days, then ate, then ate regularly on the eat days. Even with this wimpy IF schedule the subjects did better."

A good summary of the health benefits......

The impact on mental health and brain function as well through the efficient use of (mitochondria) energy and the utilization of both lysosomes and peroxisomes, which become more active during protein restriction and ketosis.

"...encourage intermittent fasting - which in combination should bring *some* ketones into the picture along with temporary protein restriction to promote autophagy......You might be surprised how you feel - not weak, but focused, energetic, and driven."

Research seems to indicate that the benefits of calorie restriction in terms of longevity in animals can be gained following several types of IF without the longterm calorie deprivation of CR practices. IF can vary from periodic three day fasting, the day on/day off model(Eat,Stop,Eat) to a daily split(ie;20/4) similar to the ones advocated within the Warrior Diet, Fast 5 and Leangains.Regardless of style even partial daily fasts seem to entail benefits....

"Eat one main meal at night, avoid chemicals, combine foods adequately and challenge your body physically. The Warrior Diet shows how to nourish the body in sync with its innate circadian clock – separating between a.m. foods and p.m. foods for effective removal of toxins, increased conversion of fat for energy, increased utilization of nutrients and improved resilience to stress. The result: a leaner, stronger and healthier body.."

 Leangains suggests a larger feeding window(16/8) which adds flexibility to scheduling but also provides specific meal plans based upon training and activity....

"The Leangains protocol consists of two phases; 16 hours of fasting, followed by 8 hours of feeding. During this period, three meals are usually eaten. Depending on the day, the composition of those meals varies; on workout days, carbs are prioritized before fat, while on rest days fat intake is higher. Protein remains fairly high on all days."

 Fast 5 falls between the two suggesting a flexible 5 hour feeding period(19/5).....

"Eat within five consecutive hours.That’s it—that's the basic summary: eat within five consecutive hours. “Eat” means consume calories according to your appetite.....During the five consecutive hours (the “eating window”), eat as much as you’re hungry for, and eat what you want to eat. Consuming liquids with calorie content counts as eating, so only calorie-free beverages are permitted during the fasting period. As long as you keep at least a nineteen-hour fast daily and eat within five or fewer consecutive hours, you’re within the guidelines of the Fast-5 program. Any window of five consecutive hours can be used."

For those following Primal/Paleo WOE's the premise of IF makes perfect sense when you view fasting in a paleolithic light. Prehistoric man probably did not have 3 square meals a day.Logic dictates it was(probably) more of a feasting WOE....periods of fasting between hunts and/or successful gathering of fruit and vegetable.

"If you buy into the idea that the Paleolithic diet is the optimal diet for us today because it is the diet we were molded by the forces of natural selection to perform best on, then you should probably also buy into the idea that a meal timing schedule more like that of Paleolithic mean would provide benefits..."                    M.Eades

Not only have we been convinced that high carb/low fat diets are the best(despite the growing evidence to the contrary) but we have also been ingrained to think that grazing is the best way to eat...smaller portions eaten more often through the course of the day. IF takes the opposite approach and suggests health benefits are gained through fasting which enables the body to reset itself, filter out toxins and rely on our fat reserves as a primary source of fuel. A little off base but an amusing modern analogy.....fueling our cars. We generally fill up the tank and then run the vehicle until the fuel starts getting low and then we top up with a "petrol feast". Do we use time and resources to stop at a gas station 3+ times a day to top up our gas tanks?

The Plan - A modest beginning is in order and I will initially focus upon just one/two day(s) a week using a 16/8 fast/feed schedule that fits well into my typical work day. My eating period will be from 1pm - 9pm on either a Monday or Friday(both usual recovery days).

No calories during the fasting stage but thanks to paleolithic nutrition I now drink black coffee and teas and have no issues consuming lots of water so that will help mitigate the lack of breakfasts. My decision to eat later in the day is based upon one undeniable would be hard making supper for the kids and not eating. The anticipation of scoffing up a good meal to end my day along with a glass of red wine would also motivate me during the morning hours to abide.

The Goal - incorporate IF into my dietary regimen going forward in a method that fits within my lifestyle and activities.

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