The effect of mealtimes on your health

Are you looking for a simple way to sleep better? A way to lower blood sugar without having to diet or count calories?

Recent research suggests that simply changing when — rather than what — you eat can trigger a host of health benefits.

The secret is to have dinner earlier, have breakfast later and not raid the fridge in the middle of the night, giving the body an extended overnight fast.

This can help improve sleep quality, lose weight, reduce blood pressure and the risk of developing type 2 diabetes.

scientific evidence

Known as time-restricted feeding, this is a promising new area of ​​research.

The idea that only changing when — not what you eat — started with experiments on mice, but in recent years there have been a growing number of human clinical trials that have shown how to extend overnight fasting (lasting 12 to 14 hours). ) can yield surprising results.

“There are observations in weight loss, anywhere between 3% to 5% weight loss. And many studies have shown improvements in glucose regulation, indicating that you are lowering your risk of developing diabetes,” says chronobiologist and clinical researcher Emily Manoogian , who leads clinical trials on the topic at the Salk Institute in California, USA.

“We also saw other types of cardiovascular benefits, such as lowering blood pressure and lowering cholesterol.”

“And high blood pressure and high glucose are the two main factors that will lead to the development of more serious cardiometabolic diseases. So if we are able to reduce them, as well as reducing obesity, it can help a lot in the prevention and treatment of diseases” , explains.

A 2019 study conducted by the Salk Institute of overweight men and women with high blood pressure and a high blood sugar showed that when participants underwent a 14-hour overnight fast, they not only lost an average of 3, 3 kg over 3 months, but also showed significant improvements in blood pressure and cholesterol level.

A small study, this time from the University of Surrey in the UK, found that asking volunteers to eat breakfast later and dinner earlier led to positive improvements in blood sugar and cholesterol levels after just ten weeks.

Additionally, animal research has revealed an impact on brain health, with time-restricted eating preventing certain neurodegenerative diseases.

hitting the pointers

But why prolonging the usual overnight fast, having dinner earlier and having breakfast later, is so good for our body?

This is partly due to our circadian rhythm — the 24-hour period on which our biological clock is based.

“Time-restricted eating is actually the third component of nutrition, which is when you eat. And the reason for that is the circadian system.”

“Physiologically and even mentally, we are a different person at different times of the day. And this is coordinated by the circadian system to ensure that everything happens in the right place at the right time,” explains Manoogian.

The variation of light, as we know, has a big impact on our biological clock – and food is also an important reference.

“Food is a stimulating cue for your brain to tell you it’s time to wake up,” notes the expert.

If you eat late at night, when your body is getting ready for sleep, it can throw your body out of sync.

“In modern society, we’ve become very good at disrupting our circadian rhythms with things like eating at random times. A lot of nutritionists say, ‘Your eyes are open, your mouth is open.’ And it’s true. This can be very disruptive to the system. circadian.”

“And chronic disruption of the (circadian) system can lead to increased rates of disease, increase weight gain, increase blood pressure, increase inflammation, it can cause a lot of problems,” warns Manoogian.

She explains that when it gets dark, our bodies start producing melatonin, the sleep hormone — which, in turn, inhibits the secretion of insulin, the hormone that controls blood glucose.

“You’re not then able to get glucose out of the blood and store it properly. You can have high glucose levels that stay high. And having that high glucose level all the time can lead to things like diabetes.”

“It’s like constantly challenging your system,” he summarizes.

Also, digesting food at night while your body is trying to rest can be problematic as your body can’t rest.

Giving your body a break at night is critical for your repair systems to kick in.

“Sleep is a time for your body to rest and recover,” explains Manoogian.

“If you’re going to fix a road, you need cars to stop passing it!”

So if you stop eating three or four hours before bed, you’re likely to notice an improvement in your sleep quality.

“In some of our trials, we found that there was a significant improvement in the number of days people feel rested when they wake up when they’re practicing time-restricted eating,” she says.

The secret is to work for, not against, your body. That is, you can reduce the harmful effects of a candy simply by choosing when to eat it.

“Therefore, time-restricted eating is a way in which we can really support our circadian system. It can do a lot to help our bodies function better,” notes the expert.

And the recommendation (and the benefits) apply to everyone — not just those who are overweight or have high blood pressure, for example.

“This really should be part of what a healthy lifestyle is.”

Coffee can?

A doubt that may arise is whether the consumption of liquids is authorized during the fasting period.

“Something like milk, I would say it can’t. There are many clinical trials that allow coffee and black tea. But there is a bit of debate about whether caffeine affects glucose regulation,” explains Manoogian.

“So I would say: just hot or cold water, whatever type of water you want, except sparkling water. Only water outside your food consumption window.”

It is worth remembering that in the period when you are authorized to eat, it is not the case of general release.

“What you eat, how much you eat, will always be important. I don’t think (time-restricted eating) is a substitute for any other nutritional advice.”

Do you want to try?

For some people, changing a habit may not be so simple. But, if you’re up for the challenge, Manoogian has some tips.

The most important thing is to choose a food consumption window that you are able to stick to within your routine, to help keep your circadian rhythm in order.

Upon waking up, it is recommended to wait at least one to two hours before having breakfast. And if you can, try to eat most of your calories in the first half of the day.

Finally, make sure your food intake window ends at least three to four hours before you go to sleep.

Ensuring you get eight hours of sleep a night will also help reinforce the positive effects of the practice—and cutting out late-night snacks will make a difference.

Time-restricted eating can work wonders for some people, but it won’t be right for everyone. Check with your doctor if you are taking medication, or have any questions, before trying it for the first time.

*In the BBC Radio 4 series Just One Thing, doctor Michael Mosley discusses in different episodes what you could do for your health if you had only one choice.

Read other stories in the series here: