2

HUMANS have been fasting since the dawn of time.

Back in the day, we’d go for hours without eating because what we ate depended on what we caught.

2

And of course, there wasn’t a Lidl or Macci Ds on every corner to tempt us.

Today, many weight loss experts claim that going back to fasting is key.

It’s worth saying of course, that if you have any history of disordered eating, fasting won’t be for you.

If you don’t and you can’t be bothered to count calories or eat certain foods, then restricting the amount of time you’re allowed to eat in might be quite handy.

But there are so many different fasts out there, it can be hard to know which one might suit you.

Writing in The Conversation, David Clayton, lecturer in nutrition and exercise physiology at Nottingham Trent Uni has been exploring the three most popular fasts

The 5:2 diet

This is a popular version of intermittent fasting is where you eat a very low-calorie diet (about 500kcal) for two days each week (any two days). On the other five days, you eat as normal.

Research has shown that it’s possible to lose weight with this diet; it also improves several markers of health, such as reducing levels of glucose and cholesterol in the blood.

But the 5:2 diet is unlikely to be more effective for weight loss than traditional methods of dieting.

This is because 5:2 reduces calorie intake to a similar extent as traditional dieting.

There is some evidence that conducting the two days of very low-calorie intake on consecutive days can improve insulin sensitivity – a risk marker for type 2 diabetes – to a greater extent than traditional dieting.

This approach also leads to decreases in blood lipids (fatty substances found in the blood) compared with traditional dieting.

An important extra benefit of 5:2 is that you can consume some food during the “fasting” period, providing an opportunity to take in vital nutrients.

Alternate-day fasting (ADF)

While 5:2 could be considered a “lifestyle intervention”, alternate-day fasting is more likely to be used to lose weight quickly.

ADF is often referred to as the “every other day diet” and requires you to alternate daily between unrestricted eating and consuming a very low-calorie diet.

It uses a similar approach to 5:2, allowing a small meal (usually about 500kcal) to be consumed on “fasting” days.

Research has shown that ADF can lead to considerable weight loss in 8-12 weeks, but a big problem with ADF is that it’s hard to stick to.

Longer-term studies have shown that calorie intake on “fasting” days creeps up over time, which reduces the calorie deficit achieved and slows the rate of weight loss.

Despite this, it is likely that ADF will result in a greater reduction in calorie intake compared with traditional methods of dieting, which should lead to greater weight loss, initially.

But it’s doubtful that many people will stick to ADF in the long term.

Time-restricted eating (TRE)

TRE involves fasting for long periods (16-20 hours) and consuming all your calories within a certain window of time.

The most common version of TRE uses a ratio between fasting and eating of 16:8 (16 hours of fasting and eight hours during which you can eat).

Many people achieve this ratio by skipping breakfast thereby delaying their first meal until midday and consuming all food between midday and 8pm.

Research has shown that calorie intake over a 24-hour period is reduced when people skip breakfast.

Skipping breakfast is unlikely to lead to meaningful weight loss. Skipping breakfast also reduces the effectiveness of insulin to regulate blood glucose levels after lunch, indicating a negative effect on insulin sensitivity.

David Clayton

But the number of calories expended through physical activity is also reduced, which will partially or completely negate the calorie deficit achieved by skipping breakfast.

So skipping breakfast is unlikely to lead to meaningful weight loss.

But an alternative approach to TRE has shown promise.

A recent study found that fasting from 2pm improved insulin sensitivity in a group of pre-diabetic males.

This could be due to an enhanced natural ability to regulate blood glucose levels effectively in the morning, due to daily variations in metabolism.

So, restricting food intake to a morning feeding window and fasting in the evening may be a healthier version of TRE.

And the winner is…

When it comes to weight loss, ADF is likely to lead to the most rapid success, but sustaining weight loss in the long term may be aided by the less intense 5:2 approach.

There is some evidence that TRE could be easier to stick to, as completely restricting food intake may be easier for some people than severely restricting it.

But any diet can only work if you stick to it.

MORE ON WEIGHT LOSS

Exclusive

BACK TO BASICS

BOSH! chefs Ian and Henry talk veganism and cooking with singer Gary Barlow

SLIM FOR SUMMER

You DO feel less hungry in the summer – it’s the best time to lose weight

DON’T WEIGHT

Weight loss tips to REVERSE type 2 diabetes – from Mediterranean diet to keto

MIND BOGGLING

Fast food could cause dementia – and damage is ‘irreversible’, scientists say

WEIGHTY ISSUE

Lose weight with the 5 best diets of 2019 – low-carb keto to Mediterranean

POP TAX

Fizzy drinks could be more expensive in restaurants to tackle childhood obesity

STEAK YOUR LIFE ON TUNA

Eating fish instead of meat can cut risk of dying early by a FIFTH

SOUR GRAPES

Does apple cider vinegar REALLY boost weight loss? We asked the experts…

FLACK ON

Lose weight like Love Island host Caroline Flack with 5 easy tips to cut sugar

DIET DILEMMA

Twins prove why some pile on weight and others don’t & it’s NOT down to food

LIFE HACKS

Lose weight and live longer with three lifestyle tweaks you can make NOW

It’s important to note that most research suggests that intermittent fasting is no better than traditional methods of dieting.

But intermittent fasting regimens that have prolonged periods of fasting, such as TRE with shorter feeding windows and 5:2 with two consecutive very low-calorie days, may provide additional health benefits.

This article first appeared on The Conversation

We pay for your stories! Do you have a story for The Sun Online news team? Email us at tips@the-sun.co.uk or call 0207 782 4368. You can WhatsApp us on 07810 791 502. We pay for videos too. Click here to upload yours