Ian K. Smith - Clean and Lean: 30 Days, 30 Foods, a New You!

The concept of intermittent fasting (IF) is not particularly new, but over the last several years it has garnered a lot of attention and new research. It is what it sounds likeperiods of fasting alternating with periods of non-fasting. While the vast majority of research has been conducted in animals, there have been more human-based studies the last couple of years that have analyzed the biological and physiologic changes that occur once a person participates in an IF program.

There are two major types of IF eating schedules. The first is the 5:2 schedule, where for five days a person eats how they typically would, then for two days of the week calories are restricted to 800 or less. The one caveat is that the fasting days should not be consecutive.

The second type of eating schedule, which you will follow on Clean & Lean, is time restricted feeding (TRF). On it, food is consumed only during certain hours and there are two periods of fasting. The duration of the feeding periods can vary. Most commonly, they are 8, 10, or 12 hours in length. For example, a 16:8 strategy includes 16 hours of fasting and 8 hours of feeding; the 14:10 strategy would be 14 hours of fasting and 10 hours of feeding.

The two IF eating schedules would look something like this:

5:2 INTERMITTENT FASTING

TIME RESTRICTED FEEDING (TRF)

Researchers acknowledge that while IF has been used for several years, and there have been studies performed to analyze the pros and cons of this eating strategy, much more work needs to be done to make validated, scientifically based claims. There have been, however, lots of anecdotal evidence about the effects of IF as well as animal studies and early human trials. While these observations are not always definitive and conclusive, they give us a clearer window through which we can inspect the potential benefits of this eating strategy. The evidence suggests that IF can help in weight loss, better regulate blood sugar levels, increase blood levels of human growth hormone, and induce cellular repair processes.

Potential Benefits of Intermittent Fasting

Weight Loss

Decreased Inflammation

Improved Asthma-Related Symptoms

Preserved Learning and Memory Functioning

Decreased Belly Fat

Reduced Insulin Resistance

Given the various research studies looking at IF, there are many theories that have been suggested as to why there might be appreciable physiological benefits. Mark Mattson, a senior investigator from the National Institute of Aging, has studied the hypothesis that during the fasting period cells are actually subjected to a mild stress. Mattson and others believe that cells react by making adaptations that increase their ability to handle this stress and possibly resist disease. Its akin to the adage, Whatever doesnt kill you, makes you stronger. In other words, fasting deprives cells of nourishment, which is stressful. But the cells change and adapt to handle tough conditions. Scientists believe that these changes make the cells tougher and better at preventing or fighting disease.