As a culture, we go through a ridiculous amount of diet phases. First, was low-fat, now it’s low-carb; don’t eat after 7 p.m., raw foods only, Whole 30… I could go on and on. One way of eating that I have been getting a lot of questions about lately is intermittent fasting.
What is intermittent fasting? Essentially, it is exactly what it says – fasting for intermittent times during the day or on certain days. There are several different fasting strategies; with the two most popular being severe restriction of calories 1-2 days per week or going 12-18 hours without eating; aka a “fasted window”. Below are a couple sample schedules of these popular strategies:
- Fasting for 12-18 hours: Eating the last meal at 7:00 p.m., then fasting until 1:00 p.m. the next day – this would be an 18-hour fast. Essentially the person is not eating after 7:00 p.m., skipping breakfast, and eating a later lunch.
- The 5:2 plan: This method involves eating normally for 5 days during the week, then restricting calories to 500-600 on two non-consecutive days.
The thought behind intermittent fasting is that eating all your food in a smaller window leads to eating less calories overall. Some research has shown that intermittent fasting may lead to weight loss. Of course; just like the beginning of any new diet; when you start to restrict calories, you will see weight loss. The problem is, the weight loss will slow because chronic restriction leads to a slowed metabolism and other medical consequences. And researchers also agree that more research is needed in the area of intermittent fasting for weight loss.
I’ve talked with several people who have tried intermittent fasting. The folks who are natural breakfast skippers thought it was no big deal; however, those that regularly ate six small meals a day said it was everything they could do to not ravenously scarf down their first meal at 2:00 p.m.
Personally, what I really want to know about intermittent fasting is:
- How hard is it really? I thoroughly enjoy breakfast and I’ve never been very successful at not eating after 7:00 p.m., so I’m guessing it would be pretty tough for me.
- Does it really result in weight loss? I am not doing anything right now to alter my weight, nor have I been trying to. However, I am interested to know if adopting this eating style for a short period of time will result in weight loss at all.
- Is it sustainable? I wonder if this eating style would work for the long term. In my opinion, this is another diet, which means it won’t be easy to stick to over time.
To answer these questions, I am going to follow a 17-hour or 18-hour time-restricted fasting window for the next 2-3 weeks (when I stop will be determined based on how much I hate it). This will not be a perfect science because I need to get creative with my schedule. Part of my job working with the eating disorder recovery group is leading supportive meals; therefore, a couple days a week I will start my eating window at 12:00 (noon) and end it at 7:00 p.m. On the other days, I will try to stay in a fasted window of 7:00 p.m. – 1:00 p.m. (18-hour fast). Just like with the ketogenic diet experiment I did a couple months ago, I will report on how things are going. Wish me luck! Resources:
Horne, B. D., Muhlestein, J. B., & Anderson, J. L. (2015). Health effects of intermittent fasting: hormesis or harm? A systematic review. The American journal of clinical nutrition, 102(2), 464-470.
Johnstone, A. (2015). Fasting for weight loss: an effective strategy or latest dieting trend?. International Journal of Obesity, 39(5), 727.
Klempel, M. C., Kroeger, C. M., Bhutani, S., Trepanowski, J. F., & Varady, K. A. (2012). Intermittent fasting combined with calorie restriction is effective for weight loss and cardio-protection in obese women. Nutrition journal, 11(1), 98.