What Breaks a Fast?

Does popping your morning multivitamin end your overnight fast? What about your favorite mug of coffee or a squeeze of lemon in your water?
If fasting is already in your wellness wheelhouse or if you’re curious about adopting a fasting practice, such questions have probably crossed your mind. From sneaky sources of hidden calories to the insulin impact of certain beverages, you may be inadvertently compromising your fasting efforts.
By definition, any intake of calories, no matter how small, ends a fast. However, with other factors taken into account, the answer is not quite black-and-white.
“So we have theory, and we have practice. And a lot of these things haven’t been researched in the academic world yet,” Samefko Ludidi, a nutrition scientist, told The Epoch Times.
“If there is no food intake, then we’re still speaking about fasting. But if we’re going to add nutrients, such as fats, then we’re not fasting anymore, but we can still stay in that desired ketogenic state. If we add sugars instead of fats, then we will immediately get kicked out of ketosis. And we won’t enjoy the benefits of that metabolic switch, as it were, anymore.”
So, if ketosis and weight loss are your goal, adding additive-free fat to your coffee will not end your fast. It can even help extend your fasting window.
“The question remains to what extent in everyday practice does a very small amount of carbs truly affect your glucose metabolism? So there is this theoretical framework, and theory [that] says fasting, strictly speaking, is just no intake of any calories, energy, fats, carbohydrates, and proteins, nothing at all. That’s theory,” he said.
“Personally, I believe that a very small amount of carbohydrates, as you could probably find in a squeeze of lemon juice, is not going to mess up your metabolism,” he added.
Ludidi explained that the total amounts of sugars and fats present in vitamins are very modest and will not kick you out of ketosis straight away. He pointed out that there is a reason you are still allowed a small amount of carbohydrates on a ketogenic diet. The keto diet generally allows for up to 50 grams of carbohydrates per day, as this is when insulin secretion is significantly reduced and your body remains in a catabolic state.
“There are two advantages of having electrolytes—especially during prolonged fasts that last longer than 16 or 18 hours,” he said.
“One, electrolytes do not contain energy, no calories, no proteins, no fats, no carbohydrates, so you will still remain in the fasted state. And two, [electrolytes] can help you to control that intense desire for food during a prolonged fast,” Ludidi noted.
He stressed choosing electrolyte mixes without added sugars or caffeine.
“The body could respond to that sweet taste by producing insulin to take up the sugars, which are not real sugars, and they don’t have the same effect as sugars,” he said. “But, they [non-nutritive sweeteners] could trigger an insulin response, [and] thereby also modulate or interfere with the fat and sugar-burning capacity that you’re playing with during intermittent fasting.”
If metabolic health is your goal for fasting, an increase in insulin levels may be counterproductive and break your fast.
“One important message here is that more is not always better. People tend to think that if one hour is good and 16 hours better, then 72 hours is the best. But more is not always better. Always listen to the signals that the body gives,” said Ludidi.
Ludidi recommends building your body up for more extended periods of fasting instead of jumping right in with a full-day fast. He suggests starting with 14 hours. Then, the following month, increasing to 16 hours, then 20, and so on, reaching a full 24 hours by the third month. He pointed out that most people are already engaging in some window of fasting without realizing it. For example, a late morning Saturday brunch.
Introducing carbohydrates could lead to fermentation, bloating, and abdominal discomfort, and suggests starting with fats or proteins, Ludidi said. Then, introducing carbohydrates only during the second meal. He noted that fats are usually very well tolerated.
Ludidi recommends starting with a small portion of eggs and meat or a very small salad with eggs, fish, or meat. Two hours later, he suggests introducing carbohydrates with your main course to allow your gastrointestinal system to start working again, especially if you go for longer fasts.
There is little, if any, existing research on the subject of what breaks a fast, according to Ludidi.
“The question is whether it’s worth putting [in] all that research money to investigate these tiny, tiny details. It would be interesting from a practical point of view because people have these questions. But, we cannot clearly say that indeed vitamin pills or lemon juice with a tiny bit, or maybe half a gram, of sugar kicks you out of ketosis or interferes with your fasting protocol,” he stated.
When it comes to what breaks your fast, you can consider the contents of the food and drinks and apply them to your goals. Check for carbohydrates, any forms of sugar, protein, fat, and the overall calorie content. Then, ask yourself whether it will break your fast.