Intermittent Fasting is a diet strategy of consuming all of your foods/meals within a given time frame of the day. The rest of the time, before and after that planned eating period, you are “fasting” and avoiding consuming calories (although non caloric beverages like tea or coffee and of course water are consider ok).
Generally, there will be an 8 hour period, like noon to 8pm, where you consume all of your calories. The strategy behind this is caloric control as you can only eat so much in a given time frame, but mostly it is practiced due to the belief that the fasting period creates a state in which the body has less readily available fuel sources in terms of blood sugar. The fasted state is believed to encourage the body to pull more from its available fat stores, making you leaner! Also, the fasting period creates greater insulin sensitivity so that when you do eat, your body will be better able to shuttle the nutrients to your muscles for greater utilization and less storage. Advocates of intermittent fasting believe that this allows them to get/stay leaner and still build/maintain muscle.
For some, the fasting period is very difficult to adhere to and can noticeably effect energy. Also, research has shown men generally tend to see better results than women, which is not surprising due to their very different hormonal makeups. How much of the weight loss is due to calorie control versus the actual diet protocols or believed hormonal adjustments is still not clear. Plus, if the feeding period is used to ingest too many calories, or too many of the wrong types of calories, then the results will obviously be effected.
Intermittent fasting may seem like an extreme approach. However, if you consider a normal 8 hour sleep period, plus not eating for 1-3 hours before you retire, you’d only need 4-5 more actual waking hours of fasting to give it a try. Like any diet strategy it has pro’s and cons and may work well from some and not so well for others. It is certainly not the only possible dieting approach. If you’re the type of person who needs fuel to kick start your day and would feel limited without eating soon upon waking (which is a great majority of people) then forcing yourself into this or any other diet approach based on results others may have seen is probably not a wise choice. But if you’re the type of person who has little desire to eat early or finds it very difficult due to lifestyle or schedule, then at least you know that there may be an option of eating which not only fits your lifestyle, but has been shown for some to be effective for fitness.
I will state that I’ve had a couple of clients who came to me from trying an IF diet approach and it had not been successful for them in terms of weight loss. Transitioning back into more structured eating was then a challenge as their caloric intake was already low and their systems were quite adapted. I have also known people who adopted an IF approach years before it became popular or marketed. They felt that “time frame eating” (as they called it) helped them to avoid indiscriminate snaking outside of their plan and caused them to focus more on giving their body the right types and amounts of nutrients during their feeding period. It was an ideal approach for them and they had plenty of energy and were quite fit.
Again, like any approach to diet there will be varying results. First consider if this sounds like something that interest you and continue to do further research. If the structure of intermittent fasting sounds like it might fit your lifestyle or mental makeup, then it may be a good approach for you to explore.