By now, most people have heard about intermittent fasting since it’s one of the most popular health trends. But in case you haven’t, intermittent fasting is simply the practice of alternating periods of eating with periods of fasting. A recent study, published in the New England Journal of Medicine, concluded that intermittent fasting has many benefits for health and aging. It may also benefit conditions such as obesity, diabetes, heart disease, cancer, and neurologic disorders (1).
What is The Best Intermittent Fast for Weight Loss?
There are mainly three widely-studied intermittent fasting approaches (see below). For this discussion, I’d like to focus on the third approach – “time-restricted eating” and its benefits for weight loss.
- The 5:2 intermittent fasting approach involves regular eating for 5 days a week and 2 days of fasting (non-consecutive). On fasting days, only one meal is eaten (500 calories for women and 600 calories for men). The fasting period occurs before and after this meal when only water is consumed.
- Alternate day fasting. This involves basically the same approach but the fasting occurs every other day instead of two days a week.
- Time-restricted eating (TRE) restricts food consumption to a 10-hour window each day, allowing for a 14 hour fast. This is known as 14:10, but many versions of time-restricted eating exist including 12:12 (the overnight fast) and 16:8.
Early Time-Restricted Eating
A common TRE approach practiced by many people today includes skipping breakfast and eating all meals between 10:00 a.m. and 8:00 p.m. However, I’ve never been a fan of skipping breakfast and eating later in the evening. So, another way to do the 14:10 fast is to eat all meals between 7:00 a.m. and 3:00 p.m. This allows for the fast to begin later in the day. There can be some flexibility with this timing plus or minus an hour.
A recent study (2) in people with metabolic syndrome (or pre-diabetes) shows this approach reduces weight, including “belly fat.” In that study, participants ate their meals between 7:00 a.m. and 3:00 p.m. This fasting method was chosen because other human studies have shown that this aligns with metabolic circadian rhythms. This means eating more food earlier in the day and reducing it by dinnertime. Studies show this method improves blood glucose control, weight loss, cholesterol balance, and reduces hunger (3).
Another recent study (4) also found that the time-restricted eating earlier in the day consistently improves health endpoints. The researchers found that an earlier eating window (dinner before 3:00 p.m.) is in alignment with the body’s metabolic circadian rhythms. They found it particularly effective for improving insulin sensitivity, blood pressure, and oxidative stress. This same study also had excellent compliance with the participants. Why? Because it’s doable. Participants even reported a decrease in evening appetite.
The Early Intermittent Fast May Help Digestion
Early time-restricted eating may also be a good approach if you want to improve your digestive system. Eating a large meal in the evening (which most people do regularly) forces the digestive organs (like the liver) to work harder. This is happening at a time when our brain is preparing to wind down for the day. Finishing up with eating by 3:00 or 4:00 p.m. is naturally aligned with digestive metabolism, which typically weakens toward the end of the day.
Combine the 14:10 intermittent fasting approach with earlier time-restricted eating. For an added bonus, walk after that last meal (at least 15 minutes). You may be on your way to lasting weight loss. If you exercise regularly, I suggest an early morning workout. Follow that with a healthy breakfast containing adequate protein.
If the earlier 14-hour fast is too difficult or interferes with family dinners, then try the overnight fast first. The overnight fast allows 12 hours between dinner and breakfast the next day.
Practice earlier time-restricted intermittent fasting at least 4-5 days a week as part of a healthy lifestyle. This is a simple habit that can have dramatic, positive health effects over time. Keep in mind, intermittent fasting and calorie restriction are not the same things. However, since the eating window is restricted, many people end up eating fewer calories anyway (bonus). So, rather than watching the scale with this weight loss approach, watch the clock instead. Let me know how it goes!
- de Cabo, R. and M. P. Mattson (2019). “Effects of Intermittent Fasting on Health, Aging, and Disease.” N Engl J Med 381(26): 2541-2551.
- Sutton, E. F., et al. (2018). “Early Time-Restricted Feeding Improves Insulin Sensitivity, Blood Pressure, and Oxidative Stress Even without Weight Loss in Men with Prediabetes.” Cell Metab 27(6): 1212-1221 e121
- Garaulet, M, et al. (2013). Timing of Food Intake Predicts Weight Loss Effectiveness. Int. J. Obes. 37, 6-4=611
- Wilkinson, M. J., et al. (2020). “Ten-Hour Time-Restricted Eating Reduces Weight, Blood Pressure, and Atherogenic Lipids in Patients with Metabolic Syndrome.” Cell Metab 31(1): 92-104 e105