A few decades ago, fasting referred to Lent or Ramadan, when the faithful stopped eating for religious reasons. But these days, it’s more likely to refer to intermittent fasting, a technique that restricts food to certain hours of the day or week. Your body cycles between a fed state and a fasting state. But how many calories break a fast? One, but anything under 10 is fine.
How Many Calories Break A Fast
Understanding Intermittent Fasting
Intermittent fasting is when you willingly stay away from food for a certain pre-set period. The most common pattern is 16/8, which means you fast for 16 hours and then eat for 8 hours. Don’t worry, you don’t have to binge nonstop! It just means you plan all your meals for the day and spread them within that 8-hour period, usually between noon and 8 pm every day.
The 8 hours when you’re allowed to eat are called your fed periods, while the 16 no-food hours are called your fast periods. How many calories break a fast during those 16 hours? A single calorie could technically break it, but this depends on your purpose for intermittent fasting. The three most common reasons why people engage in intermittent fasting include:
- Triggering ketosis for weight loss.
- Lowering blood sugar to manage diabetes.
- Resolving insulin resistance to cure diabetes.
Let’s explain these terms a bit more. Your body needs the energy to power your cells and keep you alive. This energy can come from carbs, protein, or fats. The body prefers carbs because they’re the easiest to break down, so they’re the most energy-efficient source of fuel. These carbs get broken down into glucose which is fed into the cells. Insulin facilitates this process.
Insulin is a hormone that’s produced in the pancreas, and without it, your cells can’t absorb any glucose. If your body has no insulin, you have diabetes type I. This means you’re insulin-dependent and have to inject artificial insulin every day to help you absorb glucose. In other cases, your pancreas does produce insulin, but your body can’t use it. This is diabetes type II.
Medical Fasting vs Health Fasting
Type I diabetes – the insulin-dependent kind – often starts in childhood or teenage. It’s incurable and you’ll have to inject insulin forever. Type II diabetes – the insulin-resistant kind – mostly starts in adulthood. If it gets worse, it can become type I when your body stops making insulin altogether. But type II diabetes can be managed and may eventually be cured.
One of the methods for managing type II diabetes is intermittent fasting. Fasting periods can help you control your blood sugar and reduce your resistance to insulin. In this case, the flavor is your biggest drawback. Why? For diabetics, it’s not calories that break the fast – it’s that sweet taste. Any trace of sugar, honey, or aspartame could trigger insulin and break the fast.
Essentially, if you’re fasting due to diabetes, stay away from anything with a sweet palate, even if it’s sugar-free gum. That saccharine note will release insulin and the insulin will mop up any glucose in your blood. If you haven’t eaten, that sudden absorption can cause a crash, insulin shock, or even a coma. That’s why diabetics continuously monitor their blood sugar.
If you’re fasting for weight loss, then any calories you consume will break your fast. Still, if you restrict yourself to 10 calories or less, it won’t disrupt ketosis. But if you’re fasting to control diabetic symptoms, you want to avoid anything that tastes sweet, because that will trigger insulin production, and insulin will immediately absorb glucose to break your fast.
Intermittent Fasting for Weight Loss
When you’re looking to get shredded – which means you want a sculpted look with bulging muscles – you’re likely to try two dieting styles. These are high-protein and high-fat diets. They’ll both be low in carbs because excess glucose (digested carbs) gets stored as fat, and fat hides your muscle tone. You want your body sourcing its energy from protein or fats instead.
With keto or paleo diets, these fats come from the food you eat, so your diet gets as greasy and oily as you can stand. But with intermittent fasting, you want your body to dig into its fat stores. By burning the fats stored under your skin, your muscles are exposed and you get a leaner, firmer appearance. You must limit your glucose intake to force your body to use fats.
These fats get broken down into ketones, and the process is called ketosis. Ketones have a distinct scent, so you’ll feel it in your mouth after a while. But the second your body gets any glucose, ketosis stops and regular glucose absorption resumes. This can be annoying since it takes 2 to 4 days without glucose to re-enter ketosis. It’s why the calorie content is so crucial.
When you’re fasting to control blood sugar, the emphasis is on avoiding sweetness. That may even include candy scents and the aroma of baked goods since these can all trigger insulin and drool! But if you’re fasting to burn fat, the goal is to avoid carbs, not calories. You could, for example, have bulletproof coffee with butter and coconut oil, but no sweetened creamers!
What Happens During the Fasting State?
Usually, when people want to lose weight, they try to eat less. They might also exercise target body parts to increase or reduce their size. But outside of liposuction, spot-training doesn’t work. Dieting doesn’t either because as soon as you resume your normal eating patterns, the weight will come right back. Often, it will increase because your metabolism is slower now.
With intermittent fasting, two things happen during periods when you’re not eating. One, your body digs into your fat stores and burns them for energy to keep you going. The ketones released are what make your mouth feel icky. You may want to reach for gum or a breath mint but be careful – it could trigger insulin and break your fast. You don’t want that mess!
The second reaction to fasting is autophagy. That’s when your body repairs itself by cleaning the junk out of your cells. It recycles proteins damaged during normal cell function. This usually happens while we’re asleep, but intermittent fasting has longer unfed periods so the cleansing process is deeper and more efficient. Autophagy starts 4 to 5 days into a total fast.
Lots of people talk about autophagy as a benefit of intermittent fasting, but that’s not always accurate. In mice, autophagy starts in 18 to 48 hours. By then, the rodent has lost 20% of its body weight and is practically dead. But in people, 4 to 5 days of fasting will make us shed 2% of body weight before triggering autophagy. You’d have to go a whole week without food!
Autophagy is a tricky topic though. It can lead to eating disorders as people progressively increase their fasting periods. Fortunately, you can try other ways to induce autophagy so you don’t need to be obsessive about (not) breaking your fast. This means you can gracefully stay hydrated as you sip your way through your unfed hours. Just don’t add any sweeteners!
How Do You Break a Fast (Or Not!)
People worry about breaking their fast because it could halt ketosis and/or autophagy. And once broken, it can take a few days to restart the cycle. It’s why most people opt for drinks that seem safer than solid food. And it makes sense that you’d look at the calories in your snack to be sure it doesn’t break the fast. But as we’ve seen, it’s more about flavor palates.
Whether you’re fasting for religious, medical, or aesthetic reasons, awakening your insulin activity will break your fast. So before you count calories, think about how the item tastes. If it’s sweet, it will trigger insulin, and it will break the fast. This includes sugar-free candy and diet soda. Opt for unsweetened low-calorie drinks like lemon water or apple cider vinegar.
You can also sneak in some black coffee if it has no sugar and no other additives. Plain water is fine, including fizzy variants, but flavored water is a no-no because the sweetness invites insulin action. You may think electrolytes and sports drinks are safe, but they have hidden sugars in their flavor mix. If you want the electrolyte effect, add salt to your water instead.
You might think a quick cup of herbal tea, a glass of milk, soup, kombucha, or a Coke Zero is safe. But even vegan milk (almond, oat, rice, soy) has carbs, and herbal tea often has a fruity palate. The sweeteners in diet coke can trigger insulin, and so can whey, or protein powder. Drinks you can take without breaking your fast include unsweetened green tea.
Counting Calories for Your Fast
How many calories break a fast? In technical terms, even a single calorie can break your fast. But realistically speaking, you can drink unsweetened fluids that have 10 calories or less and still keep your body in its fasting state. The key thing is to avoid triggering insulin release, and anything that tastes sweet – with or without sugar – will wake those digestive hormones.