March 25th, 2017|Nutrition, Fat Loss|
Intermittent Fasting - What You Can Eat & Drink - Myolean Fitness

“I’m doing Intermittent Fasting. What can I eat and drink during my fast?”

“Can I eat/drink [insert food/drink] during my fast?”

“Does x number of calories break a fast?”

“Will drinking BCAAs break my fast?”

“Do artificial sweeteners break a fast?”

All these are commonly asked questions by people who engage in different types of intermittent fasting, whether that’s alternate day fasting, the Lean Gains protocol, 5:2, and so on. And all are perfectly valid questions to ask, mind you.

Unfortunately, however, the answers to the questions above are a little more complicated and less straightforward than you may think. Don’t you worry, though, because, by the end of this article, your questions will be answered!

By the way, big shout out to the IF Facebook group, if that’s what brought you here!

Key takeaway points

If you’re in a rush and don’t have time to go through the entire article, here are some of the key takeaways:

  • Intermittent fasting is, essentially, an eating pattern which involves alternating periods of little or no energy intake (i.e. caloric restriction) with intervening periods of normal food intake, on a recurring basis.
  • There are three types of intermittent fasting: alternate day fasting (ADF), whole day fasting (WDF), and time-restricted feeding (TRF).
  • Fasting can mean one of two things: 1. completely abstaining from food, and 2. eating sparingly or abstaining from some foods.
  • Different people fast for different reasons, including to lose weight, to improve their health, to test their mental toughness, and for religious reasons.
  • Fat loss is the result of a caloric deficit. According to research, when calories and protein are controlled for, fasting per se doesn’t seem to increase fat or weight loss. This means that you don’t, technically, have to fast to maximize fat loss, which makes the question of what you can eat or drink during a fast when your goal is fat loss kind of irrelevant to begin with.
  • Most research on intermittent fasting for improved health and longevity suffers from serious methodological limitations. What we currently know from research is that there MAY be health and longevity benefits to fasting, but that there is, currently, no strong evidence from research in humans in the absence of caloric restriction to support this. This also makes the question of what you can eat or drink during a fast when your goal is better health and longevity kind of irrelevant to begin with.
  • Despite the above, there are still good reasons why you should try intermittent fasting, such as better caloric control, improved hunger awareness, the ability to have bigger and more satisfying meals, more social flexibility, potentially improved sustainability and better dietary adherence, and improved productivity during the fasted state.
  • A good general rule is that ingesting calories breaks a fast. While a splash of milk or cream in your coffee will, technically, break your fast, it won’t interfere with your results as long as those calories are accounted for.
  • BCAA products (all of them, despite what the nutritional label on the product says) contain calories and will break your fast.

Okay, so let’s get right into it!

What is Intermittent Fasting?

Before we talk about what you can eat during a fast, let’s first briefly explain what intermittent fasting is.

Simply put, intermittent fasting is, essentially, an eating pattern which involves alternating periods of little or no energy intake (i.e. caloric restriction) with intervening periods of normal food intake, on a recurring basis.

There are, generally, three different types of intermittent fasting according to research:

  • Alternate day fasting (ADF), which involves a 24-hour fasting or very low calorie period, alternated with a 24-hour ad libitum eating period.
  • Whole day fasting (WDF), which usually involves 1-2 days of fasting or very low calorie periods per week, with the remaining days of the week eating at maintenance.
  • Time-restricted feeding (TRF), which involves a fasting period of 16–20 hours and a feeding period of 4–8 hours daily, and includes the Leangains protocol by Martin Berkhan. This is probably the most popular of the three types of intermittent fasting.

An example of a TRF protocol is as follows: you may set your fasting period to be from 10 pm on one day until 4 pm on the following day. This gives you 18 hours of fasting and an eating window of 6 hours (from 4 pm until 10 pm every day). This is known as the 18:6 protocol among those practicing intermittent fasting. 

Other protocols are 14:10 (fasting for 14 hours), 16:8 (fasting for 16 hours), 20:4 (fasting for 20 hours) and so on.

Which leads us to our next question.

What exactly is fasting?

According to the Merriam-Webster Dictionary, to fast can mean one of two things:

  1. to abstain from food, Intermittent Fasting - What You Can Eat & Drink During a Fast - Myolean Fitnessand
  2. to eat sparingly or abstain from some foods.

As you can understand, since fasting can, technically, mean both completely abstaining from food AND eating a little/not eating some foods, we’re in a bit of a pickle.

Remember when, at the start of this article, we said that things are not as straightforward as you may think? Well, this is partly why.

Hold your horses, though, because this is going to get a little more complicated.

Why would someone fast in the first place?

The motives behind why people fast are also something important to consider when trying to decide what you can eat and drink during a fast, as this can affect what you are technically “allowed” to have.

So why do people fast?

Well, different people fast for different reasons, the most common ones being:

  1. to lose fat and weight,
  2. to improve their health and increase longevity,
  3. for religious reasons, and
  4. to test their “mental toughness”.

What you can eat and drink during a fast

Okay, so let’s consider the reasons we listed above for why people fast and try to figure what you can eat and drink during your fast for each of these reasons.

1. Fasting for fat loss and weight loss

To answer the question of what you can eat and drink during your fast when your primary goal is weight loss, we must first consider how fasting helps with weight loss in the first place.

In short, the general line of thinking goes like this: When doing IF, the fasting periods result in lower insulin levels and higher human growth (HGH) hormone levels which, in turn, cause increased fat burning and, consequently, weight loss.

Is this, however, an accurate description of what happens? Well, according to scientific research, it’s true that, when we fast, our insulin levels drop and our HGH levels increase. What does research show, however, with regards to the end result, i.e. actual fat and weight loss? Do fasting-related lower insulin levels and higher growth hormone levels really result in more fat loss?

With regards to insulin, we can look at research comparing low carb/ketogenic diets with energy- and protein-matched higher carb diets for the answer, since these were designed to examine whether insulin per se plays a key role in fat loss. In short, a number of well-controlled studies such as this metabolic ward studythis metabolic ward study and this meta analysis provide good evidence to support the idea that low carbohydrate diets and ketogenic diets don’t seem to work better for fat loss when caloric and protein intakes are controlled for.

With regards to human growth hormone, research on intermittent fasting can shed some light. In short, studies that have compared intermittent fasting approaches to continuous energy restriction while controlling for caloric and protein intakes, such as this one, this one, and this one, have shown that, overall, the two diet types result in identical outcomes in terms of body weight and body fat reduction.

Why is that, however? If lower insulin levels and higher growth hormone levels aren’t the reasons why intermittent fasting works for fat loss, then how does intermittent fasting work?

Well, as we’ve talked about before, fat loss is the result of a sustained imbalance between energy intake and output. Simply put, to lose fat we have to take in fewer calories than we expend consistently over time. This is indisputable, by the way, and supported by every well-controlled study in the history of ever.

And this is, essentially, how intermittent fasting (and every other diet approach) works for weight loss – by helping you eat less, overall.

Intermittent Fasting - How it Works - Myolean Fitness

So where does this leave us with regards to what you can eat and drink during your fast?

Well, in reality, if your only goal is weight (and fat) loss, you can technically eat and drink anything you want at any time of the day, provided that you are maintaining a caloric deficit.

Eating throughout the day, of course, means that you won’t be doing intermittent fasting. And, yes, this means that you don’t HAVE TO do intermittent fasting if it isn’t practical for you and if it doesn’t help you adhere to your diet.

Remember, intermittent fasting is merely a meal timing tool which is supposed to help you control your caloric intake.

Take home point:

If your primary goal is to lose weight, the answer to the question “can I eat/drink [whatever] during my fast?” is “you can, technically, do whatever you want, as long as you are maintaining a caloric deficit consistently over time.

However, if you are consuming foods/drinks with calories, you wouldn’t be fasting. But it doesn’t really matter, since it’s not the fasting per se that causes fat and weight loss, but, instead, the fact that intermittent fasting helps most people eat less overall.”

2. Fasting for better health

Next on our list is fasting for better health.

Okay, so you don’t, technically, have to fast to lose weight, but fasting can improve health and increase longevity, right? After all, scientific research has shown that fasting results in a number of health benefits, including:

Well, unfortunately, if you take a closer look at the studies most health blogs usually cite, you will realize that the available scientific research suffers from a number of serious methodological problems, including that it is mostly limited to:

  1. animal studies – a number of systematic reviews such as this one, this one, this one, this one, and this one, have demonstrated poor clinical utility of animal experimentation,
  2. in vitro studies – i.e. with microorganisms or cells outside their normal biological context, usually in a test tube or petri dish,
  3. mechanistic studies i.e. studies discussing how one thing might affect another, but not actually trying it and seeing it happen in real life, and
  4. studies that don’t control for caloric intake  caloric restriction and weight loss have been shown to have a multitude of health and anti-aging benefits in countless of studies. Since intermittent fasting tends to result in caloric restriction, it’s difficult to attribute the health benefits found to fasting per se, when there is the confounding variable of energy balance.

In short, what we currently know from research is that there MAY be health and longevity benefits to fasting without caloric restriction, but that there is, currently, no strong evidence from research in humans to support this.

“But this article/study says that fasting has health benefits”.

Okay, before you rush to any conclusions, investigate further!

Don’t just accept what the news website reports or what the abstract of a study says as facts just because they tell you what you want to hear. More often than not, claims are, at best, exaggerated by news websites, while study abstracts usually don’t tell the full story.

Intermittent Fasting Increases Lifespan - Myolean Fitness

Remember to check the four points above, i.e. that the study referenced:

  1. is not in animals,
  2. is not in vitro,
  3. is not mechanistic in nature, and
  4. that it controls for energy intake.

So where do the above us with regards to what you can eat and drink during your fast when fasting for increased health and longevity?

Well, simply put, focusing on just fasting to improve your health is missing the forest for the trees, since it doesn’t look like it’s fasting per se that has health benefits but, instead, the overall decrease in energy intake as well as the accompanied fat loss.

Take home point:

Fasting MAY have some health benefits, but there is no strong scientific evidence to support this yet, so don’t stress about x food/drink breaking your fast or not. Remember that there are a few things that you can do that are much more important than fasting.

If you want to improve your health, make sure that, above all, you are:

  • maintaining a healthy weight,
  • eating a diet that is based on plants, lean proteins and healthy fats,
  • exercising regularly,
  • not smoking,
  • not drinking excessively,
  • not stressing, and
  • maintaining healthy social relationships.

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3 & 4. Fasting for religious reasons and to test mental toughness

Fasting for these reasons is more of a personal matter and beyond the scope of this article. If your religion says that you have to completely abstain from foods for so many hours or from some foods for so many days, it’s entirely up to you to decide whether you want to do it or not.

The same applies to fasting for mental toughness. If you want to test your limits and see how long you can fast for, it’s your decision to make.

Just bear in mind that prolonged fasts can be dangerous and should, preferably, be done under the close supervision of a licenced health professional.

Why do Intermittent Fasting then?

So if fasting per se isn’t what results in weight loss and health improvements, why then do intermittent fasting in the first place?

Well, although fasting doesn’t seem to have any “magical” properties in and of itself, there are a number of good reasons why you should consider doing intermittent fasting! This is, after all, why we often use this approach with many of our online fitness coaching clients!

So here are a few reasons why you should consider doing intermittent fasting (credit to the Pinned Post of the official Intermittent Fasting Facebook group for these):

1. More structured eating

How often have you found yourself mindlessly snacking between meals? A couple of cookies with your coffee, a small piece of cake that Suzy brought for her birthday at work, a few nuts and dried fruits before dinner, some popcorn with a movie at night. When you think about it, little snacks here and there can add up to quite a few calories. Well, the more structured eating that is a result of intermittent fasting can eliminate this problem and can help people better control their diet.

2. Bigger, more satisfying meals

Eating every 2-3 hours sucks. For one, it’s impractical and makes you think of food all day. It also means that you never really get to eat big meals, especially if you are a smaller, physically inactive person. On the other hand, more infrequent meals that are larger in volume and provide more calories are usually much more satisfying and may help you feel fuller for longer.

3. Sustainability and adherence

Diets that control calories over the long term lead to weight loss success. Eating larger meals less frequently usually tends to increase adherence to the diet over the long haul.

4. Social Flexibility

Humans are social creatures and most of us nowadays tend to build social occasions around food, with these occasion usually taking place in the evening. By fasting throughout the day, you enable yourself the freedom to eat the foods served at social gatherings while still staying within your calorie goals for the day. Remember, a diet that doesn’t promote social flexibility is really hard to maintain.

5. Improved hunger awareness

When eating throughout the day, it’s not uncommon to eat for reasons other than hunger. For example, many people tend to eat because of boredom, sadness, stress, or happiness. Also, even the smell of food can make us think we’re hungry and cause us to want to eat (walk by a bakery and listen to your stomach growl!). Well, fasting can help improve hunger awareness, making you realize what real physical hunger feels like and how to differentiate it to “hunger” arising from environmental or psychological factors.

6. More productivity

Since eating takes up time, having fewer meals can often help people get more stuff done during the day, thereby, increasing productivity.

Let’s recap

Okay, so with all the above in mind, let’s recap and try to answer all the questions asked at the beginning of the article.

“I’m doing Intermittent Fasting. What can I eat and drink during my fast?”

If you are doing intermittent fasting to lose fat and weight, you can technically eat and drink whatever you want at any time of the day, provided that you are maintaining a sustained caloric deficit over the long term. This means that IF may help you lose fat if it makes it easier for you to reduce overall energy intake, but that you don’t HAVE TO do IF to lose fat and weight.

If you are doing IF for the purported health and longevity benefits of fasting, you may be disappointed to hear that we don’t know for certain if these exist in humans yet. There are a few things you can do that will have a much larger impact on your health anyway, such as maintaining a healthy body weight, eating a diet that is based primarily on plants, lean meats, fish and healthy fats, exercising, not smoking, not drinking excessively, not stressing too much, and maintaining healthy social relationships, so it’s a better idea to focus your energy on these instead.

“Can I eat/drink [insert food/drink] during my fast?”

Does eating/drinking that food or drink make it easier for you to improve your overall diet in terms of better food quality and lower calorie intake? If yes, go for it. If no, don’t.

“Does x number of calories break a fast?”

There’s no set number of calories that breaks a fast. The person who first came up with this probably did so to allow people to have a splash of milk or cream in their coffee without stressing about it, but to also keep them from going overboard with the calories and not managing to create a caloric deficit by the end of the day.

“Will drinking BCAAs break my fast?”

Despite what most people think (and what the nutritional info label on your BCAA product says) ALL BCAA products contain calories. Leucine and isoleucine contain 4.65 calories per gram, while valine contains 4.64 calories per gram. With the typical 2:1:1 ratio of most BCAA products, this means that 10g of BCAAs contain around 46.5 calories.

So yes, BCAAs break your fast. However, it doesn’t really matter if they do or don’t in the first place.

“Do artificial sweeteners break a fast?”

Artifical sweeteners contain, practically, no calories, so they don’t break a fast. For example, a typical can of aspartame-sweetened soda contains less than half a calorie.

Also, contrary to what many people think, artificial sweeteners don’t cause insulin secretion (diabetics would be dropping dead everywhere if this was the case) or somehow make you gain fat or weight (the association between artificial sweetener consumption and obesity in research doesn’t imply causation – it most likely means that people who are overweight tend to switch to diet soda in an effort to lose weight).

What next?

If you enjoyed this article and found it informative, you’ll probably also like these ones as well:

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