Intermittent fasting is a diet that involves consuming your food in a specific time period every day - for example, no breakfast before 12pm; no dinner after 6pm. If you are going to fast, make it a lifestyle choice not a crash diet. Start it gradually to get your body slowly into the new diet.
The daily approach: The simple concept is to aim to fast every day for 16-18 hours a day and only consume your food in the remaining six to eight hours. For example, if you eat your evening meal at 6pm, then you would not eat your next meal until at least 12pm the following day, allowing an 18-hour fast in between.
The weekly approach: This suggests that you eat normally five days a week and diet two, preferably consecutive, days a week, reducing your calorie intake for those two days to a quarter of their normal level (500 calories for women, 600 for men). As long as you avoid bingeing for five days and starving for the other two, evidence suggests this can be effective as part of a longer-term weight management strategy.
Start gradually: To start with, increase the gap between dinner and breakfast. If you're not hungry you could skip breakfast altogether; going from dinner to lunch works best. Consider the ideal ratio of 16:8 hours, this means you'd be eating a lower-calorie but nutrient dense diet within the eight-hour window. Typically, this would be from midday until 8pm. Spread this over two meals and then fast until lunch the following day. Repeat this routine at least two to three times per week.
If you feel hungry any time outside of the eight-hour window, distract yourself with an activity or task so that you're not so aware of the hunger pangs. Factoring in a daily brisk walk will help to speed up your metabolism and maintain muscle mass. If you're opting for the weekly approach, do not fast for longer than three days in a row to avoid a significant reduction in your metabolism and to protect against muscle loss. If you've embarked on this approach on a long-term basis, including a cheat day every now and again is not a problem.