Choosing the Wrong Plan
There are so many different forms of intermittent fasting, so be sure to choose the one that works with your schedule, needs, and lifestyle. "Fit the fasting into your life schedule, not the other way around, otherwise you'll never be able to stick to it in the long term," Dr. Fung suggested.
Do your research and choose an IF plan that you'll be able to stick with. One type called 5:2 involves eating 500 calories a day (600 calories for men) twice a week and eating normally the other five days a week. If you have a demanding full-time job, an active family, and an intense workout routine you want to stick to, eating that few calories will feel impossible on those days. So the 16:8 plan, where you fast for 16 hours every day, will probably be easier to maintain; it allows you to just skip breakfast and have a feeding window from 11 a.m. to 7 p.m.
Remember that you can be flexible from day to day. If you have an important social event, shift your fasting window to accommodate that or skip that day's fast and do it the next day. The flexibility of intermittent fasting is what makes it so sustainable.