Intermittent fasting is a hot topic these days, and many people are giving it a try. Some recent research suggests that benefits might include management of weight, heart disease, type 2 diabetes, sleeping problems, as well as slowing down the aging process. The truth of the matter is that research is still lacking, and we do not know the long-term effects of intermittent fasting. However, people have been practicing intermittent fasting in their current routines, and many people love the results!
There are three popular types of intermittent fasting. All involve a pattern of rotating periods of eating with periods of fasting.
Alternate Day Fasting
- Alternate day fasting refers to rotating days of eating and days of fasting. On fasting days, no foods or beverages with calories are consumed (calorie-free drinks, such as water, black coffee, and tea are allowed). On non-fasting days, you can eat a healthy balanced diet without trying to restrict calories. This type of fasting will enable you to eat a “restricted diet,” just half the time.
- Modiﬁed fasting involves eating very little amounts of food on fasting days. Some modified fasts restrict intake on fasting days to 20-25% of needed calories. Others limit intake on fasting days to only 500 calories. Commonly, participants of modified fasting may follow a 5:2 fast, meaning that they follow their usual eating pattern 5 days per week and fast 2 days per week.
- Time-restricted fasting limits the intake of calories primarily for waking hours. The goal is to fast 8-12 hours each day with the bulk of the fast occurring during sleep. This type of intermittent fasting allows one to structure an eating routine that allows food intake 12-16 hours per day. This method is a good option for people who would rather not snack after their last meal or do not eat breakfast immediately upon rising.
Theoretically, intermittent fasting works because it cuts the total number of calories over a week that you would have typically consumed if you were not fasting. Over time, by eating fewer calories, you can promote weight loss. It is helpful to think of your intake as a weekly average rather than a daily/24-hour cycle. On some days we eat more, and some days we eat less, but in general, over time, our body weight is naturally regulated.
In my opinion, time-restricted fasting may help individuals structure an excellent dietary routine. For example, one may decide not to eat anything after 9 p.m. in the evening and resume eating between 7-9 a.m. the following day. This allows one not to consume unnecessary calories in the form of late-night snacks and may help establish a healthy eating pattern.
At this time, intermittent fasting is not currently recommended for weight loss, and it may also pose a health risk for certain individuals. It is not recommended for people with diabetes, women who are pregnant or breast-feeding, and individuals with a history of disordered eating. Anyone considering fasting should first discuss it with their doctor or a Registered Dietitian.