Intermittent Fasting has become one of the most popular dietary patterns in recent times. It is most popular within the health & fitness industry and many people are tinkering around with it to see if they can benefit from the plethora of health benefits associated with it.
Some of the most common questions surrounding fasting is;
What actually breaks a fast? And, can I have coffee?
The first question is fairly easy. Simply put, you’re eating or you’re not. Now for the coffee.
For most people, I wouldn’t be too worried about whether or not this is the case. The fact that you are already going 12-24 hours without any caloric intake places you ahead of the curve simply by being open to the idea that you don’t have to eat every other hour. Some coffee with full-fat cream isn’t really going to take away what you’re trying to accomplish.
Some people however, myself included, like to look a little deeper. So… let’s start with black coffee.
Here is how black coffee affects some of the more common fasting benefits.
Fasting is a quick and easy way to get into ketosis. You don’t have a choice in the matter. As your body depletes its glucose supply, it will automatically begin to break down excess body fat to produce ketones as a fuel source.
This study found that the consumption of caffeine boosted ketosis in humans.
Fat burning is another popular benefit of fasting. As stated earlier, coffee has been shown to increase ketosis, so it would be safe to say that coffee also increases fat mobilisation and burning.
In the short-term, fasting can reduce insulin sensitivity. This is a physiological measure taken by the body to preserve the little glucose that is remaining for the brain.
The real benefits occur over the long-term, where fasting is an effective way to improve your insulin sensitivity and glucose tolerance. Just about everything that makes you more efficient at fat burning and expending energy, rather than the storing of energy, like exercise, low-carbohydrate diets and fasting, tend to improve insulin sensitivity over time.
Coffee has a similar effect. In the short-term it reduces insulin sensitivity and glucose tolerance. With long-term use, coffee improves both insulin sensitivity and glucose tolerance. Many studies have found that the more coffee you drink, the lower your overall risk of developing type-2 diabetes.
Basically, it’s cellular cleanup. Autophagy is one of the ways that the body keeps its cells healthy and maintained, by recycling dead or damaged cells. Fasting is one of the best ways to induce autophagy. It is actually one of major selling points for fasting.
That covers black coffee. What about the common additions to coffee?
Coffee with butter, coconut oil or MCT oil
Technically, this is breaking the fast. If you’re consuming calories (and depending on how much fat you add, it could be a significant amount of calories), these calories break the fast.
Pure fat however, has little to no effect on insulin, blood glucose, or any other measure that would indicate a broken fast.
By adding some fat to your morning coffee, you won’t be burning as much body fat. You will however still be burning a lot of fat.
It will most definitely help you fast for longer periods. For some people, adding some fat to coffee can make fasting more tolerable. If you can go 12 hours on black coffee, but a tablespoon of MCT oil can help you get 16-24 hours, then the addition of MCT oil is probably a good thing.
It shouldn’t affect autophagy. It’s protein consumption that interrupts autophagy. Butter has a small amount, but it shouldn’t interfere unless you’re consuming it in large amounts.
Coffee with cream
An ounce of full-fat cream has almost a gram of carbohydrate (lactose) and protein. Some cream in your coffee won’t affect your fat burning very much, but it might reduce the amount of autophagy. The point here is that your coffee should be black with maybe a tablespoon of full-fat cream.
That being said, if you’re fasting you may be already eating a paleo or ketogenic type diet which have been shown to increase autophagy. This is all a matter of degree and probably still a net win.
The takeaway here is that some autophagy is not zero autophagy.
Coffee with almond / other nut milks
Firstly, why? Black coffee all the way please. Maybe a little full-fat cream. Ok, I there are a lot of people who can not tolerate diary and can’t really stomach black coffee. Enter the almond / other nut milks.
As long as you’re staying away from the sweetened versions, or those fortified with additional proteins, and you’re not having half a cup or more at a time, then a little nut milk won’t make much of a difference.
There isn’t much nutritionally to most nut milks.
Coffee with collagen
Collagen is one of my favourite things to add to my black coffee. It is however, pure protein. Consuming protein tends to increase mTOR and inhibit autophagy. All this means is that having collagen in your coffee during a fast will probably help with fat burning and suppress your appetite for longer, but it will reduce the benefits of autophagy.
Try black coffee. Nothing beats it. Drip. Pour-over. Espresso. Long blacks. Whichever the method. It’s the simplest way to maintain a fast.
Ask for full-fat cream. A lot of coffee houses will stock it. Just be careful when using the “cream” that is set out for customer use. That will usually be cream mixed with milk, giving you too much of a protein and carbohydrate hit that will potentially break the fast.
Avoid nut milks. A lot of places will use sweetened nut milks to add flavour to their coffees. They’ll also overdo the amount. An almond latte will have up to 8 ounces of almond milk, which will definitely break your fast.