You may of heard of “intermittent fasting” as one of the new catch-terms for dieting and weight loss. Much like “keto dieting”, there can be a lot of misconceptions and misunderstandings about how dietary restrictions can help or possibly hurt individual weight loss goals. When done appropriately, there is sufficient evidence that may suggest intermittent fasting techniques can help achieve individual goals for weight loss. There are three techniques that have some evidence supporting efficacy for weight loss:
- “5:2 fasting”: Eat routinely (ie, good, healthy calorie and nutrient appropriate meals) for 5 days of week. On two, non-consecutive days eat approximately 1/4 to 1/3 of your usual caloric intake. For most, this is 500-800 calories per day, usually as split between two meals usually rich in protein and healthy fats.
- Time restricted feeding, or “TRF fasting”. Potentially the easiest through daily lifestyle modification, this method involved limiting food intake into a window of time. This is often split as 16:8, meaning you fast for 16 hours and feed in an 8 hour window. For example, one may eat from 8am to 4pm, then fast from 4pm to 8am. Other common splits are 14:10 or 12:12. A recent publication in the NEJM suggests benefits as far reaching as a weight loss, age longevity, cancer, diabetes, and heart disease.
- 24 hour fasting, or alternate day fasting. In this method, calories are restricted to 500-600 per day every other day alternated with calorie dense meals. While the “off-days” allow for more liberal calorie intake, the subsequent days are more frequent and restrictive. This has been suggested in a recent JAMA in reducing body weight by 6% more over other fasting methods.
As always, you should contact your primary doctor before starting any new diet plan.