ADVERTISEMENT

The author of the 5:2 diet tested the popular theory that eating carbs at night is bad for you — and the results suggest we've got it all wrong

Dr. Michael Mosley said there was a "clear winner" — but it wasn't the one he was expecting.

  • Many people think that a carb-heavy diet is bad for you and that when
  • you eat carbs counts — at dinner is worse than at breakfast, they say.
  • Michael Mosley, the doctor who developed the so-called 5:2 diet, put the theory to the test in a new episode of the BBC Two program "Trust Me I'm a Doctor."
  • A small study with a group of "healthy volunteers" showed that it's better to eat carbs at night.
ADVERTISEMENT

It's a common belief that eating late at night — particularly anything carb-heavy — can ruin an otherwise good diet.

However, Michael Mosley, the doctor behind the so-called 5:2 and blood-sugar diets, put the theory to the test as part of a new BBC show, and the results suggested this isn't true.

The 5:2 diet, based on intermittent fasting, involves eating pretty much whatever you like for five days a week, then for two nonconsecutive days restricting calories to 500 for women and 600 for men.

ADVERTISEMENT

However, calorie-counting is just one method for weight loss.

Diets high in refined carbs, such as white bread or pasta, have been tied to outcomes like weight gain and obesity, contributing to the rise of the low-carb diet.

"If you eat lots of carbohydrates and sugars, particularly the sort without fibre that get quickly absorbed, they will rapidly push up your blood glucose (sugar) levels," Mosley wrote in a BBC article.

He said that if this glucose isn't burned through some activity, the pancreas responds by releasing insulin into the bloodstream to bring the levels down again, storing the excess sugar as fat.

"Too much stored fat, particularly visceral fat (inside the abdomen) can lead to serious health problems such as type-2 diabetes," he wrote.

ADVERTISEMENT

But Mosley says many people have also come to believe that when you eat carbs also counts.

"It's widely believed, for example, that eating carbs in the evening is worse for you than having them for breakfast," he wrote.

It's thought that if you load up on carbs in the morning, you can burn the glucose during the day's activities, he said.

In the latest episode of "Trust Me I'm a Doctor," which will air on BBC Two on Wednesday January 17 at 8.30 p.m., Mosley works with Dr Adam Collins from the University of Surrey to put the theory to the test in a "small" study.

ADVERTISEMENT

They set out to discover how well the bodies of a sample of "healthy volunteers" would cope with eating most of their carb intake in the morning, or in the evening. They also wanted to find out if the body learns to adapt over a period of time, he said.

The participants were all given the same daily carb allowance, and in the first phase of the experiment, ate most of this at breakfast time. They then had five days of eating "normally" before swapping to eating high-carb meals in the evenings for another five days.

Their blood sugar levels were monitored throughout.

Ahead of the experiment, Dr Collins said: "It's always made sense to me that we process carbs better if we have a whole day of activity ahead. So, I expect having most of their carbs at breakfast will be easier for their bodies to cope with.

"But we don't really know what happens if you regularly follow an evening-carbs diet," he added. "There's never been a study like this before, and as a scientist I'm excited to see what happens."

ADVERTISEMENT

The results surprised Mosley, who said there was a "clear winner," but not the one he was expecting.

The results showed that the average blood glucose response of the participants in the the initial stage of the test was 15.9 units, which was "roughly as predicted."

But during the final five days of the study this went down to 10.4 units, "which was considerably lower than we were expecting," Mosley said.

"[It] could be that what matters is not so much when you eat your carbs but the length of the carbs-free 'fasting' period that precedes your meal," Mosley said.

ADVERTISEMENT

"If you've had a big gap since your last carb-rich meal, your body will be more ready to deal with it. That happens naturally in the mornings because you've had the whole of the night, when you were asleep, in which to 'fast.'

"But our small study suggests that if you go low-carb for most of the day, that seems to have a similar effect."

He added: "In other words, after a few days of low-carb breakfasts and high-carb dinners your body becomes trained for this — it becomes better at responding to a heavy carb load in the evening."

Collins is now planning a larger study on the topic, according to Mosley, in search of more definitive answers.

For now, he says Collins is advising people not to focus so much on when you eat carbs — provided you are consistent and "don't overload with them at every meal."

ADVERTISEMENT

"It's more about achieving peaks and troughs," Mosley wrote. "If you've had a lot of carbs in the evening, try to minimise them in the morning.

"On the other hand, if you've had a pile of toast for breakfast, go easy on the pasta that night."

The author of the 5:2 diet explains why eating healthy is more important than exercise

FOLLOW BUSINESS INSIDER AFRICA

Unblock notifications in browser settings.
ADVERTISEMENT

Recommended articles

US troop withdrawal from Niger hangs in the balance

US troop withdrawal from Niger hangs in the balance

Detained Binance executives sue Nigerian authorities for human right violation

Detained Binance executives sue Nigerian authorities for human right violation

Nigeria's central bank increases minimum capital base for banks

Nigeria's central bank increases minimum capital base for banks

Sony’s creators convention redefines the creative landscape for content creators

Sony’s creators convention redefines the creative landscape for content creators

Exploring the popularity of progressive jackpot slots in Indonesia

Exploring the popularity of progressive jackpot slots in Indonesia

Egypt, Nigeria, and South Africa ranked as Africa's most polluted countries in new report

Egypt, Nigeria, and South Africa ranked as Africa's most polluted countries in new report

10 African countries with the lowest life expectancy according to the World Bank

10 African countries with the lowest life expectancy according to the World Bank

Kenyan women are more obese than their men - here’s why

Kenyan women are more obese than their men - here’s why

Africa’s richest man Dangote stands between Europe and $17 billion in revenue

Africa’s richest man Dangote stands between Europe and $17 billion in revenue

ADVERTISEMENT