Food just doesn’t taste the same when you’re hungry — and now researchers know why.

Japanese researchers found that neurons that express proteins called Agouti-related peptides (AgRP) alter how your taste buds work when fasting. These neurons are found in the hypothalamus, a region of the brain that helps regulate appetite.

The researchers selectively activated AgRP-expressing neurons in mice that were fed just recently. Switching on these neurons enhanced the mice’s appetite for sweets and increased their tolerance to bitter tastes — similar to the conditions observed during fasting.

Normally, your body does not find bitter foods appetizing because bitterness signals that the food you’re eating has gone off. Meanwhile, sweets have always been enticing because sweetness signals that you’re munching on a rich source of energy. But when you’re hungry, you have an easier time eating bitter foods and an increased appetite for sweets.

Health benefits of fasting

Fasting often gets a bad rap because it deprives your body of food. But it can actually be good when done right. Here are a few reasons why should try fasting:

Improves blood sugar control

Wish to keep your blood sugar levels in check? Try fasting! A study of 10 people with Type 2 diabetes shows that short-term intermittent fasting significantly decreases blood sugar levels. Another study reports that both intermittent fasting and alternate-day fasting were as effective as limiting calorie intake at reducing insulin resistance. Decreasing insulin resistance can boost your body’s sensitivity to insulin, the hormone that regulates blood sugar levels.

Fights inflammation

Chronic inflammation puts you at risk of chronic conditions like heart disease, cancer and rheumatoid arthritis. Thankfully, fasting helps fight inflammation. One study shows that intermittent fasting for one month significantly decreases levels of inflammatory markers.

If you’re hesitant to fast, you can follow a low-calorie diet to mimic fasting conditions and still be able to experience the anti-inflammatory benefits of fasting. Studies show that doing so reduces levels of inflammation and aids in the treatment of multiple sclerosis, a chronic inflammatory condition.

Boosts heart health

Fasting promotes a healthy heart in a lot of ways. Studies show that fasting lowers blood pressure levels and reduces levels of “bad” lipoprotein cholesterol, total cholesterol and triglycerides. Fasting is also linked to a lower risk of coronary artery disease and diabetes, which is a major risk factor for heart disease.

Boosts brain function

Fasting also has a powerful effect on your brain. It improves brain function and brain structure and increases the production of nerve cells. It also helps fend off neurodegenerative disorders like Parkinson’s and Alzheimer’s by relieving inflammation.

Protects against cancer

Fasting can also fight off cancer. Test-tube studies show that exposing cancer cells to several cycles of fasting is as effective as chemotherapy at delaying tumor growth and increases the effectiveness of chemotherapy drugs on cancer formation.

Promotes weight loss

Abstaining from all or certain foods decreases your overall calorie intake, which therefore promotes weight loss. But fasting’s weight loss benefits do not stop there. Short-term fasting can boost metabolism by increasing levels of the neurotransmitter norepinephrine. Higher levels of norepinephrine in the body can speed up fat loss by stimulating the release of fats that your body burns for energy. In fact, researchers say that whole-day fasting can reduce body weight by up to nine percent and significantly decrease body fat in as early as 12 weeks.

Increases secretion of growth hormones

The human growth hormone (HGH) is a type of protein that plays a central role in growth, metabolism, weight loss and muscle strength. To increase HGH levels, try fasting. Studies show that fasting for a day boosts HGH secretion and sustains high HGH levels by maintaining healthy blood sugar and insulin levels. Long-term increased levels of insulin can reduce HGH levels.

Delays aging

Aging is scary because it signals the imminent end of life. No worries. Fasting can actually slow down aging and even extend your lifespan. In fact, mice that fasted every other day experienced a delayed rate of aging and lived 83 percent longer than rats that didn’t fast.

Types of fasting

Once you’ve decided to fast, you have to choose which type of fasting to do. Check out the following types:

• Water fasting — You can only drink water for a certain period.
• Juice fasting — You’re allowed to drink only vegetable or fruit juice for a set amount of time.
• Intermittent fasting — Your intake is partially or completely restricted for a few hours up to a few days at a time, while a normal diet is resumed on other days.
• Partial fasting — You are required to eliminate certain foods or drinks like processed foods,
  animal products or caffeine for a set period.
• Calorie restriction — Your calorie intake is restricted for a few days every week.

Keep in mind that fasting is not for everyone. If you’re a diabetic, fasting can lead to dangerous spikes and crashes in your blood sugar levels. Adolescents, older adults and underweight individuals should also avoid fasting without the recommendation of a health professional.

Otherwise, fasting is a healthy option for people who are looking to lose weight or increase their appetite for bitter greens. If you decide to try fasting, drink plenty of fluids and eat nutrient-dense foods during your eating periods for better results.

Sources:

ScienceDaily.com

Healthline.com

BNRC.SpringerOpen.com