Although intermittent fasting refers to any diet strategies that restrict eating during specific days or times, the most popular are forms of “time-restricted feeding”.
Time-restricted feeding means that you only eat during certain times of the day. With this kind of restriction, many people find it easier to lose weight, but the benefits go beyond just weight loss. Intermittent fasting promotes metabolic flexibility and contributes to greater overall health, here’s why.
1. Lose weight
By only eating at certain times, intermittent fasting makes it easy to eat fewer calories. Common strategies include eating during a specific window of time or “fasting” 1-2 days a week. For example, skipping breakfast and eating from 11 a.m. to 6 p.m or only eating 1 meal a few days of the week.
After adapting, people feel less hungry outside those windows and end up eating fewer calories overall. The weight loss resulting from intermittent fasting is about equivalent to a constant level of calorie restriction.
The balance between calories coming in and calories being burned is the main factor in weight gain or weight loss, so it's easy to see why intermittent fasting can be so helpful for people who want to lose weight.
Intermittent fasting isn't for everybody. While somebody may balk at the idea of not eating 2 days out of the week, someone else may think it's impossible to not eat breakfast. Check out these weight loss programs to see what strategy will be right for you.
2. Burn fat
Intermittent fasting doesn’t just help you lose weight, it may specifically help to lose body fat.
Fasting for long enough to let your glucose reserves go down forces your body to rely on stored body fat for fuel, thus the demonstrated increase in fat burning seen in studies on intermittent fasting.
When combined with a lower carb higher fat diet, you may become even better at burning calories stored as body fat.
Remember that any diet that helps you lose weight needs to be accompanied by an increase in physical activity to prevent muscle loss.
3. Improve metabolic flexibility
Metabolic flexibility is being able to use any fuel (i.e. carbohydrates or fats) to satisfy the energy demands of daily life.
Some people’s body never gets the chance to adapt to nutrients besides carbohydrates. With an engine stuck in one gear, it becomes harder to shift to new fuels.
Intermittent fasting, however, allows you to use the nutrients after a meal, your stored glycogen (which can last a full day or 2 ½ hours of physical activity), and the stores of energy in your body fat.
By forcing your body to cycle through different nutrient stores, intermittent fasting improves your ability to clear blood sugar and burn fat.
4. Periodic ketosis
With emerging science showing how important ketones are for healthy metabolism, intermittent fasting may be a great option if a full-on ketogenic diet seems too restrictive for you.
Being in a state of ketosis models some of the benefits of fasting, with weight and diabetes control being some of it’s best uses.
Since the metabolism-boosting effects of ketosis may change over time, some argue that you should only be in ketosis sometimes — not all the time — anyway.
A higher fat diet or the “5 days on, 2 days off” intermittent fasting regimen are good ways to increase your chances of periodically getting into ketosis while intermittent fasting.
5. Reduce inflammation
Chronic inflammation and a constantly overactive immune system are leading contributors to the widespread chronic diseases facing the modern world.
Many of these problems are intertwined with caloric excess, making intermittent fasting a straightforward and appealing option to reduce systemic inflammation.
Excessive immune activation, cardiovascular disease, type 2 diabetes, non-alcoholic fatty liver disease, rheumatoid arthritis, and cancer are all examples of inflammatory diseases that might benefit from intermittent fasting.
Keep in mind that most studies on the long-term effects of intermittent fasting on chronic diseases have only been done in animals. That said, most show consistently positive effects.
6. Boost your brain
One of the areas of research that looks to be very promising, but hasn't delivered the high-quality clinical trials we need yet, is in the relationship of intermittent fasting to brain health.
One animal study shows that intermittent fasting may prevent dementia. Some (but not all) studies show that it can even reduce the brain levels of tau and beta-amyloid proteins, key players in the progression of Alzheimer's disease.
What few clinical trials have been done on humans also show beneficial effects on the brain.
One study shows that in older adults who regularly fasted, the practice helped prevent cognitive decline over the course of three years. Others show cognitive-enhancing effects among people who fast regularly for religious or cultural purposes.
7. Improve heart health
Having specific eating windows is so helpful for managing blood pressure and blood cholesterol that the American Heart Association’s scientific committee issued a statement clarifying their beneficial role.
The catch? The research showed that although regular, and consistent time-restricted feeding can be beneficial, irregular eating patterns were consistently associated with negative health outcomes.
Apparently, skipping breakfast is only detrimental when it’s out of necessity, but not when it’s a planned part of your day.
So, choose a plan that you can stick with in the long term and make it your consistent eating pattern to consistently see results.
8. Improve blood sugar and insulin sensitivity
Even without weight loss, intermittent fasting may be a way to help people at risk of prediabetes or type 2 diabetes.
“Short-term studies of TRE (without weight loss) have shown improvements in insulin sensitivity and fat oxidation, and reductions in blood pressure and appetite,” Dr. Elizabeth Thomas, a research physician at the University of Colorado, told University of Colorado Press.
When you give your body time to clear the natural post-meal increase in blood glucose, you give it a chance to become insulin-sensitive again, a component of a healthy metabolism.
9. Circadian regulation
Natural cycles based on light and dark have a large impact on the daily cycles of your hormones like cortisol and melatonin.
Eating late at night is linked with more body fat and poor metabolic health than people who eat during the day. One study even shows that shifting an eating window to noon – 8 pm is late enough to lower the benefits of intermittent fasting compared to eating earlier.
When you're intermittent fasting you naturally eat less food at night and get those calories in during the day. Harmonizing the signals your body receives from what is in your control (your diet) and the factors outside of your control (your environment) sets your health up for success.
10. Cellular housekeeping
In nature, for every ebb there is a flow: times of plenty alternate with times of fasting.
In modern civilization, on the other hand, it is all too easy to be constantly growing and gaining.
We hardly give our bodies the time to clear out inefficient and inactive cells, which puts our brains at risk for Alzheimer’s disease and our bodies at risk for infections and poor metabolism.
The process of cellular housekeeping, called “autophagy”, is beneficial because it lets your cells perform their essential maintenance duties. This may be one of the reasons intermittent fasting can be so effective for health and longevity.
When you’re eating frequently, your body never gets the chance to clear out old cells, leaving you to work with dysfunctional machinery. Give your body a break so that it can function its best!
Even though intermittent fasting may be most known for weight loss, its beneficial effects extend to many, if not most, chronic conditions.
Here are some of the major benefits:
- Intermittent fasting helps you lose weight by decreasing the amount of calories you eat in a day. This straightforward method may be easier for some to adhere to than other dietary strategies. For other effective weight loss programs, see our list here.
- Intermittent fasting effects outside of weight regulation have to do with improving metabolic flexibility. Being able to use glucose, glycogen, fats, and ketones contribute to a healthy metabolism.
- Going for periods without food gives your body a chance to clear out old unhealthy cells and lay the groundwork for healthy growth.
- Reducing inflammation, facilitating autophagy, and aligning your hormones with natural daily cycles may all contribute to the effect of intermittent fasting on brain health, heart health, blood sugar regulation, and a generally healthy metabolism
Intermittent fasting is not for everyone. If you are at risk of an eating disorder or have an advanced disease, always talk with your healthcare provider before changing your diet or lifestyle.