Most people enjoy a well-earned lie-in on Saturday, meaning their breakfast gets pushed back to brunch. 

But eating meals later on the weekend may cause extra weight gain – even if you consume the same amount of calories – research suggests. 

Scientists found people who ate three-and-a-half hours later on weekends had BMIs that were 1.3 units higher on average than those who stuck to their weekday routine.

This was still the case despite the quality of their diet, how long they slept or how much they exercised. 

Disruption to normal eating schedules can result in extra fat around the waistline because our bodies aren’t used to processing food at that time.

Eating meals later on the weekend may cause extra weight gain, even if you consume the same amount of calories, research suggests (stock)

Eating meals later on the weekend may cause extra weight gain, even if you consume the same amount of calories, research suggests (stock)

Eating meals later on the weekend may cause extra weight gain, even if you consume the same amount of calories, research suggests (stock)

University of Barcelona researchers, behind the study, say our biological clocks, called circadian systems, prepare the metabolism to break down food at specific times.

Cells are programmed in this way so they know when to spend energy taking up or utilising specific nutrients. 

Eating at a different time catches the metabolism off-guard. It means the cells are slow and sluggish at breaking down fat, they say. 

The researchers surveyed more than 1,100 students from Spain and Mexico to come to come to the finding.

They asked participants what time they normally ate breakfast, lunch and dinner on weekdays and weekends.

Almost two-thirds ate meals an hour later on their days off and breakfast was the most delayed meal, tending to become brunch.

The study found the greater the time difference between weekday and weekend meals, the more likely they were to be overweight. 

Later than three-and-a-half hours seemed to cause the most extreme weight gain. 

People who did this on their days off had a BMI 1.3 units higher than participants who ate at roughly the same time on weekdays and weekends. 

Dropping 1.3 BMI units is equivalent to someone who is 170cm tall and weighs 14 stone (90kg) losing half a stone (4kg).

Lead researcher Maria Fernanda Zerón-Rugerio said the results suggest overweight people could use meal timing as a fat loss method.  

She told New Scientist: ‘Say you usually have breakfast at 7am but then on weekends you have it at 9am. 

‘Your biological clock doesn’t know it’s the weekend so it’s going to prepare your body to eat at 7 am, and then it gets confused when you actually eat at 9 am.’  

Responding to the study, Mhairi Brown a London-based nutritionistm said it was an ‘interesting study’. 

But she added that calorie reduction was the a proven measure that should be implemented first and foremost.   

Simple calculation that shows how many calories you should REALLY eat each day to lose weight

Being in a calorie deficit is the only way to lose weight. That means you have to be burning more calories than you’re consuming.

The ideal intake can vary hugely depending on your Basal Metabolic Rate (BMR).

BMR is the amount of calories we expend just to keep our body going.

When taken into account with your activity levels it can have a huge bearing on how many calories you need to consume.

Your BMR can be found using a number of ‘macro calculators’ found online.

They take into consideration your age, work and exercise levels. 

Once you calculate your BMR, you subtract around 250 calories for steady weight loss, or 500 calories for aggressive weight loss. 

Additional exercise – such as a walk or run on the treadmill – can also be used as a tool to expend more calories, thus adding to your calorie deficit.

For example, a brisk half-hour walk on the treadmill may burn 250 calories.

How to calculate your Basal Metabolic Rate 


10-17 years BMR = 13.4 x weight (kg) + 692

18-29 years BMR = 14.8 x weight (kg) + 487

30-59 years BMR = 8.3 x weight (kg) + 846


10-17 years BMR = 17.7 x weight (kg) + 657

18-29 years BMR = 15.1 x weight (kg) + 692

30-58 years BMR = 11.5 x w eight (kg) + 873

Once you’ve got your BMR, you need to combine it with your activity rate. 

Inactive men and women: BMR x 1.4 

This applies to anyone whose job isn’t physically demanding, for example, someone who mostly sits in an office at a desk all day. You don’t have any form of structured exercise in your life and if you do, it’s low intensity such as walking.

Moderately active women: BMR x 1.6 

Moderately active men: BMR x 1.7

This applies to someone whose job is more physically intense or involves bein on their feet a lot. They would also take part in structure exercise of moderate intensity around three times a week. 

Very active women: BMR x 1.8 

Very active men: BMR x 1.9 

Someone with a very physically demanding job who also does some structured exercise, or someone who does intense exercise for an hour a day. 


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