What is intermittent fasting? How the weight loss diet works and potential benefits
THE term 'intermittent fasting' has been bandied about a fair amount in recent years, with a host of celebs and influencers touting the diet's health benefits.
Put simply, it's an eating plan where people switch between fasting and eating on a regular schedule.
Fasting means going without food, so if you regularly skip breakfast you might unwittingly be following a type of time-restricted eating.
Research suggests that intermittent fasting could help with weight loss and managing conditions like cholesterol.
But the diet is certainly not suitable for everyone.
From different methods to how it affects your body and the health pros and cons, here's what you need to know about intermittent fasting.
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What is intermittent fasting?
Though many diets focus on the what foods you're eating, intermittent fasting is all about when you eat.
It's a type of eating pattern that involves restricting when you can eat to a certain time window.
The idea behind intermittent fasting is that it gives your body a break from digesting food, potentially leading consuming fewer calories than if you were eating more regularly, according to .
Eating less may also have positive effects on your blood sugar levels, which can be useful if you have prediabetes or type 2 diabetes, it added.
Intermittent fasting may also trigger a process called autophagy, where your body works to remove damaged cells from your body.
Your body does this when it doesn’t have to focus on digesting food.
Intermittent fasting has become increasingly popular among celebrities and influencers, with the likes of Hugh Jackman, Jennifer Aniston and Kourtney Kardiashian confessing to following the trendy diet.
Fans claim it can have a host of health benefits, including weight-loss and a boosted metabolism.
Research also has shown time-restricted eating can improve blood pressure, blood sugar and cholesterol in the short-term.
But other studies have raised concerns over the diet's impact on heart health.
Meanwhile, experts at warned that intermittent fasting can leave you feeling cranky or lethargic and could cause you to overeat after fasting periods.
It may also be dangerous to skip meals or limit calories if you have conditions like diabetes, and fasting may not be for you if you take medications for blood pressure or heart disease.
That's because you may be more prone to imbalances of sodium, potassium, and other minerals if you go without food.
And it can be best to take certain drugs with food to avoid nausea or stomach irritation.
How does intermittent fasting work?
There are a few different forms of intermittent fasting, some of which are more restrictive than others.
Popular examples include:
- The 16/8 method: A fasting window of sixteen hours and an eating window of eight hours - you can drink water, milk, tea and coffee while fasting
- The 5:2 method: You pick two days a week where you consume about 500 to 600 calories, while following a normal, balanced diet on the remaining five
- The 24 hour fast: Not eating for a 24-hour period, either monthly or weekly
- Alternate day fasting: Fasting every other day, which Bupa says can be difficult to maintain in the long-term
There are a number of ways to shorten your eating window - chances are you've already done it by accident.
It can include:
- Having a later breakfast
- Skipping breakfast altogether
- Having an early dinner
What are the benefits of intermittent fasting?
According to short-term studies, intermittent fasting may help you lose weight if you're consuming fewer calories overall and sticking to healthy foods when you do eat.
Meanwhile, a study conducted by National Clinical Research Center for Geriatric Diseases showed that following the eating regime may help reduce people’s “addiction” to food by rewiring the brain.
Some have suggested that intermittent fasting can have health benefits for those with - or at risk of - developing type 2 diabetes, such as weight loss and helping control blood sugar.
But if you type 2 diabetes, it's important to consult a medical professional before trying the eating plan.
Though it might help blood sugar control and reduce insulin resistance, it can also lead to dangerously low blood sugar if you take medications like sulfonylureas and insulin.
Is intermittent fasting healthy?
Intermittent fasting could yield some health benefits in the short term.
But Chinese researchers recently warned that people who followed the diet by eating in an eight-hour window were 91 per cent more likely to die of cardiovascular disease than those who ate normally over 12 to 16 hours.
Dr Victor Zhong, of Shanghai Jiao Tong University, said: “We were surprised to find that people who followed time-restricted eating were more likely to die from heart disease.
“Even though this type of diet has been popular due to its potential short-term benefits, our research clearly shows that a shorter eating duration was not associated with living longer.
“It’s crucial for patients, particularly those with heart conditions, to be aware of the link between an eight-hour eating window and increased risk of cardiovascular death.”
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While intermittent fasting can be safe for healthy adults to try in the short-term, Bupa notes that you shouldn't try it if:
- If you are pregnant
- Have type 1 diabetes
- Have a history of disordered eating
- Have anxiety or depression
Celebs fans of intermittent fasting
OVER the years, a number of celebs have confessed to giving intermittent fasting a go.
One high profile acolyte of the trendy diet is Jennifer Aniston, who told Radio Times in 2019: "I do intermittent fasting, so there's no food in the morning."
Her preferred way of intermittent fasting is the 16:8 method: "I noticed a big difference in going without solid food for 16 hours," Jen said.
Another lover of the 16:8 fasting routine is Hugh Jackman, who tried fasting to get his ripped Wolverine physique.
When Pussycat Doll Nicole Scherzinger doesn't have time to hit the gym due to her busy schedule, the star pushes back her first meal of the day to around lunchtime.
Another celeb who's tried her hand at intermittent fasting is Kourtney Kardashian.
She explained on her lifestyle site that she often wouldn't eat for 14 to 16 hours after dinner.
"I wouldn't eat past 7pm at night and then I would wait to eat the next day until after my morning workout, which would be around 10:30am. or 11 am," she said.
"Then, one day a week, I did a 24-hour fast."
During those fasting days, she would only drink bone broth, water and green tea.