Intermittent fasting has a large fanbase as a way to lose and maintain weight in a sustainable way. So, what is it? Does it work? And is it really all that different from other diet alternatives?
What is intermittent fasting?
Intermittent fasting (or IF for short) is a schedule for eating that alternates between periods of unrestricted eating and periods of fasting. Fasting in this case usually allows for nutrient- and calorie-free beverages such as coffee, so long as you skip the creamer and drink it black. Unrestricted eating, on the other hand, means you eat anything you want—cake, steak and potatoes, a bag of apples, it’s all on the table (pun intended) so long as it’s within your eating window.
Popular intermittent fasting schedules
What an IF schedule looks like can vary pretty widely. On the more extreme end, some people follow a schedule that allows for normal eating 5 days a week, with 2 full days of fasting. While the 2 days shouldn’t be back-to-back, this can still be a difficult schedule for people to stick to.
More common are IF schedules that include an eating window every day. A 16:8 schedule (16 hours of fasting, 8 hours of eating) is one of the most common schedule. Some evidence also suggests that people may eat less and feel more satiated while eating on this schedule. In practice, a 16:8 schedule might look like skipping breakfast, eating a big lunch at 11:00 am, snacking through the afternoon, and then having a big dinner at 6:30 pm. No late snacks allowed.
A 14:10 schedule allows for more typical eating patterns. With a 10-hour eating window, this schedule might include a late breakfast at 9:30 am, lunch at noon, dinner at 5:30 pm, and snacking while watching evening TV until 7:30 pm. For many, this can be an easier schedule to maintain, but it might not restrict calories enough to be as effective for weight loss.
There is evidence that suggests women might want to avoid longer fasting schedules. One study found that women showed an impaired glucose response after 3 weeks of alternate-day fasting. There has also been concern that extended fasting may have unwanted hormonal effects for women, leading to a general recommendation for women to err toward shorter fasting windows.
How does intermittent fasting work?
IF can work to aid weight loss by reducing calorie intake. By limiting when you can eat, IF has the effect of limiting how much you can eat. That’s why more restrictive eating windows appear to produce the biggest caloric deficits.
Ultimately, IF is like any other diet plan that works by reducing your caloric intake. When you consume fewer calories than you expend, your body turns to fat and other calorie stores to cover the difference, resulting in weight loss.
Can I really eat anything I want?
One of the allures of IF is the free pass to the all-you-can-eat buffet. Technically, yes, you can eat milkshakes for 8 hours, then fast for the next 16 and you haven’t broken the rules. That’s not to say the diet will still work though! If you eat more calories than you expend, you’ll still gain weight, even if you eat it in the approved window.
Caloric deficit aside, it’s also important to continue making healthful food choices. While you can eat anything you want on an IF diet, bodies need a good balance of macro- and micronutrients to stay healthy and reach fitness goals. If you aren’t sure your IF diet meets these needs, BXF trainers provide diet and nutrition consulting.
Is intermittent fasting right for me?
IF is right for you if it works with your lifestyle in a way that is sustainable over time. IF differs from other diets by reframing how you think about dieting. Instead of thinking about what to eat (or obsessing over what you can’t eat), it asks you to think about when you eat.
For some, IF can make dieting easier. Since the diet allows anything to be eaten, it can help avoid the feeling of sacrifice that comes with many diets. It also removes the hassle of counting calories and may also help reduce the feelings of food obsessing that can come with it. The focus on timing also reduces the need to make diet-approved food choices throughout the day, which can wear down will power. You either can eat or you can’t. For some, that lack of choice takes the pressure off.
On the other hand, IF creates a rigid eating schedule that can clash with the things you want to do. Will you need a snack during an early-morning hike? Do you like to socialize around food late in the evening? These sorts of situations can test your ability to stick to an IF schedule.
At Body by Ford, we encourage clients to eat consistently from day to day, whether on an IF schedule or not. Consistency, more than anything, leads to diet success and allows for moderate tweaks to your diet over time to keep on track with your weight loss and health goals. In our work with clients, we find that drastic dietary changes and aggressive dieting rarely work over the long haul. You can learn more through a free consultation with one of our trainers.
