I've been doing 5:2 intermittent fasting since February 5, 2015, except for a total of 8 weeks when I was traveling. (I am writing this February 2016.) It has worked very well for me. I've lost 28 pounds so far. I'm near my weight-loss goal and feel good. Charlie started 5:2 fasting last summer and he is near his goal as well. After we reach our goal, we plan to continue to do intermittent fasting to maintain the weight loss and for the health benefits. But probably only one day a week instead of two.
Here are resources that we've found helpful for learning about and doing various types of intermittent fasting.
This is the entertaining documentary that got me started. Dr. Michael Mosely looks into various fasting methods and ultimately settles on a type of intermittent fasting he calls "5:2 fasting": eat normally 5 days a week and restrict calories to 500 (women) or 600 (men) two days a week.
Instructions for getting started, some tools, a good forum.
The article talks about daily intermittent fasting: eating all your calories within a restricted time window. For example, each day eat everything within 8 hours, then fast for 16 hours. This is called "16/8 fasting". I liked this quote from his article:
Diets are easy in the contemplation, difficult in the execution. Intermittent fasting is just the opposite — it’s difficult in the contemplation but easy in the execution. Most of us have contemplated going on a diet. When we find a diet that appeals to us, it seems as if it will be a breeze to do. But when we get into the nitty gritty of it, it becomes tough... Intermittent fasting is hard in the contemplation, of that there is no doubt. "You go without food for 24 hours?" people would ask, incredulously when we explained what we were doing. "I could never do that." But once started, it’s a snap. No worries about what and where to eat for one or two out of the three meals per day. It’s a great liberation. Your food expenditures plummet. And you’re not particularly hungry... Although it’s tough to overcome the idea of going without food, once you begin the regimen, nothing could be easier. — Dr. Michael Eades
A discussion of several intermittent fasting methods.
This is Dr. Mosley's book about 5:2 fasting. Nice to read but not necessary. His website gives plenty of information.
If you are going to be counting calories some and find it hard to figure out calories from recipes, this is a great. (From website caloriecount.com.) You can type in a recipe and it spits out the nutrition information. It’s fast and free. I didn’t sign up. After I put a recipe in, to save it, I take a screen shot. I try to figure out how big a serving I want (in ounces/grams) and adjust the number of servings so one serving comes out to that. If you want to convert grams to ounces, or vice versa, just type into Google something like “2 oz to grams”. You’ll get an immediate answer. You can click on “Tips and Instructions” below the input box for examples of how to put in quantities, etc. I’ve been amazed how easy it is to use. Once you’ve put in the ingredients click on "Analyze Recipe". If they don’t understand one of your ingredients they’ll prompt you to choose something from a menu or do a search.
The study involves (1) IER: Intermittent Energy Restriction, i.e. intermittent fasting such as fasting or calorie restriction 2 days a week or alternate days and (2) TRF: Time Restricted Feeding, e.g. eating all food say within a 6 hour period during daylight hours. On page 5, it says there haven’t been very many human studies of these. Also it says in human studies done with TRF, showed no improvement with healthy normal weight subjects. But does work with obese mice. It says animal models have consistently shown that IER inhibits and even reverses the growth of a range of tumors.
This says that intermittent calorie restriction (CR) and daily calorie restriction are "equally as effective in decreasing body weight and fat mass, although intermittent CR may be more effective for the retention of lean mass."