Intermittent fasting has become a popular tool for people these days, but what’s the best way to break a fast? First, it’s important to define intermittent fasting; the definition typically varies depending on who talks about it.
We consider intermittent fasting as periods of 24 or more hours of fasting. The 16:8 fasting protocol, while often referred to as intermittent fasting, falls under what we consider time-restricted eating. Why the distinction?
The vast majority of the population follows some level of time-restricted eating. While they may not have it locked down to a specific time period, people don’t eat when they sleep. In this way, you can say everyone performs intermittent fasting because that perform time-restricted eating by not eating while asleep.
So we refer to scheduled periods of the feeding/fasting cycle as time-restricted eating. We consider intermittent fasting as periods of prolonged fasting of 24 hours or more. The distinction clarifies the 2 and differentiates them from the default state of eating while we are awake and fasting while we sleep. Otherwise everyone is doing intermittent fasting AND time-restricted eating,
The discussion today centers around breaking an intermittent fast. There are several things to consider when breaking a fast: What to eat when to break it, how much to eat, and so on. So what’s the best way to break a fast of 24 or more hours?
Today we’ll cover what to eat, how much and when.
What to eat when you break a fast
When breaking a fast, it’s important to consider what you are going to eat. For the most part, people who are new to fasting gorge on basically anything and everything. This is not an approach we endorse.
Depending on the length of your fast, it’s important to consider food quality. During longer fasts of 3 days or more, you often become depleted of water soluble vitamins and electrolytes, many of which are important for carbohydrate metabolism.
Consuming large amounts of carbohydrates at this time, particularly if you are coming off a keto diet, is not advised. Refeeding syndrome is a concern, albeit not likely in a relatively healthy person.
Refeeding syndrome is a dangerous shift in electrolytes that can lead to cardiac, neurological, or respiratory problems. The risk increases depending on how you enter your fast and your general health.
Again, a relatively healthy person likely won’t experience it. But if you enter a prolonged fast already malnourished, it’s a cause for concern. Ideally, a nutrient dense meal rather than junk food is the best option to break a fast.
A mix of carbs, fat, and protein will ensure a more balanced blood sugar response to the end to your fast. If you’re following a Keto diet prior to your fast, simply start back on it.
Balanced: Salad w/dressing, chicken thigh, roasted potatoes
Keto: Ribeye, avocado, & asparagus
How much to eat when you break a fast?
How much a person eats when they break a fast often depends on how long the fast lasted. One of the drawbacks of doing a dinner-to-dinner fast is that people will typically eat a gi-normous amount of food in a single meal, as dinner is typically your last meal.
There are drawbacks to this approach. First, insulin sensitivity is lower in the evening. This effect is driven by our circadian rhythms. Second, our appetite is controlled by 2 drives: a circadian drive and a homeostatic drive.
The circadian drive simply causes us to be hungrier at night, and the homeostatic drive causes us to be hungrier the longer we go without food. Having these 2 drives line up at night may drive substantial overeating that could negatively effect sleep.
Additionally, digestion is better earlier in the day, again via circadian rhythms. Eating a large meal at night in and of itself can disrupt circadian rhythms via nutrient sensing pathways and by increasing core body temperature.
Ultimately, how much you eat to break a fast is determined by the number of meals you have the day of breaking your fast and the length of your fast. Dinner-to-dinner fasting kind of hamstrings you into eating a huge dinner.
For long fasts, we don’t recommend dinner- to dinner fasting because it’s just too much food to consume at a single meal at night. For a 24-hour fast, it’s less of a problem, and we recommend eating a normal-sized dinner and making up the extra calories the next day.
Breakfast-to-breakfast fasting is much easier to accommodate. Simply make up some or all of the calories you missed on your fast by increasing intake proportionally at each meal. Fasting is a useful tool to decrease calorie intake, but you don’t want to cause too much of a deficit. It also may have benefits that extend beyond calorie restriction.
When to break a fast?
The next important question is when to break your fast. Many people don’t really think of this important factor. Most of the time, people stick to intervals of 24 hours, but that’s not necessary. You can fast any amount of time that fits your needs: 24, 28, 36, 42, etc.
Assuming you go for a 24-hour fast, many people start with a dinner-to-dinner fast. This means that the last meal they eat is dinner and don’t eat again until the following dinner, skipping breakfast and lunch. This is an easier way to introduce yourself to fasting, but is not ideal for some people based on the information mentioned above.
There’s no doubt that it’s easier to eat a big dinner and skip breakfast and lunch. But my personal goal is to push for an “early-bird” circadian rhythm, as I believe this is ideal and works great for me. Part of this is eating most of my food earlier in the day.
As such, eating dinner as my last major meal and then not eating again until having a large dinner goes against what I’m trying to do. That doesn’t mean it won’t work for YOU, it’s just not right for ME.
I don’t typically fast for much over 24 hours anymore. But when I do, and even during 24 hours fasts, I go breakfast-to-breakfast or dinner-skip-a-day-breakfast. Additionally, I stick to scheduled meal timings consistently, unless I’m trying to shift them.
One of the purported benefits of time-restricted eating is that it creates anticipatory responses to scheduled meals. Essentially, when we eat on the same schedule day in and day out, there are anticipatory responses that optimize appetite, digestion, glycemic response, metabolism, etc.
The anticipatory responses to scheduled meals are proposed to improve appetite regulation, digestion, and metabolism. The mechanisms driving these anticipatory responses are neuroendocrine and driven by changes in hormones such as ghrelin, insulin/glucagon, GLP-1, and other hormones and neurotransmitters.
Ghrelin: An example of the anticipatory response to meals
We covered the importance of the hunger hormone ghrelin in a blog you can check out here. Ghrelin peaks prior to scheduled meals and appears to function as a motivator to seek out food.
In essence, when food consistently presents itself at the same time, we get hungry at that time and that motivates us to search for food. Consider it a relic of the past when we didn’t have unfettered access to food and anticipating when it presents itself had its advantages.
As discussed in the blog, ghrelin may have other important effects that prepare the gut and rest of the body for digestion. But the important take-home here is that ghrelin peaks before scheduled meals. If you have irregular feeding patterns, aka you don’t eat on a schedule, you won’t get the benefits of the anticipatory response.
The general trend in human observational and clinical trials indicates a cardiometabolic benefit to regular meal timing. Two clinical trials in women found lower daily insulin output in a regular meal pattern vs an irregular meal pattern. This was regardless of obesity status.
Thus, maintaining a consistent meal schedule may provide both digestive and cardiometabolic benefits. When breaking a fast, stick to your normal meal schedule and break it at a normally scheduled meal time.
Many people have taken to intermittent fasting as a way to improve health and maintain a healthy weight. It’s certainly a useful tool for these purposes, but it’s not a panacea. It works for some, but in others can be disastrous.
Taking a pragmatic approach to breaking a fast may have additional benefits. Winging it can create more problems than it solves, so it’s a good idea to have a plan of attack.
As a general practice, it’s best to exit your fast by returning to your previous scheduled meal composition and timing. Of course, this is contingent on having a schedule in the first place, which appears to have benefits to digestive and cardiovascular health.
If you’re trying to lose weight, it’s important to create a calorie deficit, but you don’t want to overdo it. If not trying to lose weight, just make up the calorie deficit by spreading out what you have to make up over ensuing meals.
Do you need help setting up your schedule? Well, you’re in luck. Next week we’re releasing a meal scheduling cheat sheet to subscribers of the email list. You can sign up for the email list in the right-hand margin of the blog or via the pop-up form.
Additionally, if you have questions on the topic of meal scheduling, send them to Dave@hackyourgut.com. The next podcast will cover this important topic in greater detail.