Eating breakfast “like a king” with a big meal at the beginning of the day could prolong your life, as long as you’re prepared for a much smaller dinner.
a new studywho looked at the effects of altering the feeding schedules of mice, suggests that changing the times at which we eat most of our food may have health benefits and make a significant difference to how long we live.
Body clock and dietetic experts agree, saying humans could gain by “jumping up” their food intake for the day with a large breakfast and lunch and a small, early dinner, an eating pattern they say , could also lead to weightloss.
The extensive studio daily Sciences found that the lives of mice were prolonged by 10 percent if they ate all their food for the day during the 12-hour period at night, when they are most active, compared to eating during the 12-hour day.
Similar studies cannot be replicated in humans because they cannot live in a laboratory and eat measured portions of the same food at precise times throughout their lives.
But mice share many similarities with people, and these latest findings add to emerging evidence that concentrating food intake, at the right times of the day, can play a key role in our health and longevity.
They suggest that humans could live longer if they ate all their food in the 12-hour daytime period when they are most active.
And narrowing the eating window a bit further, while advancing consumption so that most of it is served in the late afternoon, could further increase longevity, experts say.
“Skipping that big dinner and having a light snack instead could help us live longer,” said Professor Russell Foster of the University of Oxford, who has just written a book on how the biological clock can be harnessed to improve our health.
“You should shift your calorie intake to the first and middle part of the day. You don’t want to concentrate all your calories at the end of the day,” she said.
“The old maxim, ‘eat like a king for breakfast, a prince for lunch and a pauper for dinner’ is the thing to keep in mind.
“The same food eaten at different times of the day can produce very different blood glucose levels due to circadian rhythm. [body clock] driven changes in glucose uptake and metabolism.”
Another academic, Tim Spector, professor of genetic epidemiology at King’s College London, gave seemingly contradictory advice this week when he suggested that people should delay their breakfasts until 11am.
His rationale was that a later breakfast was needed to allow for a 14-hour fasting period because people now tended to eat until 9 p.m.
Fasting “works because the microbes in our gut have a circadian rhythm just like us and they need a rest period,” he said at the Cheltenham Science Festival.
Professor Foster, Director of the Sleep and Circadian Neuroscience Institute at the University of Oxford, also believes we should eat according to our natural rhythms, but he has a different solution: stop eating late at night.
“Evening eaters, who eat much of their meal for the day between 6 p.m. and bedtime, are at much higher risk for glucose intolerance, type 2 diabetes, weight gain and obesity,” he said.
“Our metabolism is completely different during the day and at night. We are taking in calories throughout the day and turning them into energy.
“But if we have calories to spare at the end of the day, we turn them into fat for storage because at night we need to use the stored energy to run our metabolism and survive.”
How meal times have changed
Front-loading our daily food intake, which is now recommended by experts, would mean a big change for many of us. But not so long was the norm.
“Until recently, this was our eating patterns,” said Professor Russell Foster, a body clock expert at the University of Oxford. “Just a few generations ago, lunchtime was commonly called dinner (and still is in many homes) and that is where most of the food was consumed.
“That was the lifestyle of the working person and they needed that food to boost their energy. But with the invasion of the night, the long commutes to work, the changes in the social structure and the ease of putting something in the microwave at the end of the day, our eating habits have changed drastically, in the last 50 to 70 years, from the first and middle of the day until the end of the day.”
“Those great Tudor banquets we thought of actually took place at lunchtime rather than in the evening. We have forgotten how quickly we change our eating habits from the first part of the day to almost exclusively the second part of the day.”
He argues that the shift to late-night is driving the nation’s weight gain, along with our increasing tiredness, making us hungrier and more likely to crave weight-gain foods.
“There is a double whammy: not only as a society have we changed the timing of our meals, we are also tired, as a result of prolonged work, we have reduced the duration of sleep. And that predisposes us to eat more and eat more carbohydrates and sugars.”
The new study in the journal Science followed hundreds of mice for four years, using automatic feeders to monitor when and how much each mouse ate throughout its life.
He tested several different settings of different amounts and times to tease out the effects of calorie intake, fasting, and circadian rhythms on longevity.
He concluded that if a mouse eats all its food during the active 12 hours of the night, it will live 10 percent longer than if it eats the same amount during the 12 hours of the day.
“Eating only during the busiest time of day substantially extended the lifespan of the mice,” said Professor Joseph Takahashi of the University of Texas Southwestern Medical Center, who led the study.
“We found profound differences in life expectancy [depending on meal timing] – the daily rhythms of the body play an important role in this longevity effect.”
In addition to comparing the effect on lifespan of eating a given diet at different times of the day, the study also found that the benefits of reducing total calorie intake might be enhanced by eating at the right time.
“Fasting alone, without calorie reduction, is beneficial,” Professor Takahashi said. “You should fast during your inactive phase of the day. A 12 hour fast is the bare minimum and some people think 14 or 16 hours is better.
“Our metabolism is programmed and regulated by the circadian clock to be able to anticipate our daily meals during the day. It is optimized to process our diet at normal circadian times of the day. In the opposite phase, our metabolism is in a different state, so eating at the wrong time can lead to weight gain and less than optimal glucose and insulin control.
“There are many versions of what is called intermittent fasting. Alternate day (AD) fasting, time-restricted eating, such as an 8-hour eating window and a 16-hour fast or a 12-hour eating window and a 12-hour fast. Most of these versions have been shown to have health benefits, but definitive longevity studies in rodents are still underway. Our article shows an extended half-life and a maximum useful life [from fasting].”
Fasting for 12 to 14 hours a day can lower insulin levels and help some people lose weight, according to a study from the University of Illinois, Chicago.
“These findings suggest that restricted feeding for 8 hours produces weight loss. It may also offer clinical benefits by lowering blood pressure,” according to the study, published in the journal Nutrition and Healthy Aging.
Fasting also gives our 100 trillion gut bacteria a break and gives them time to clear mucus from the intestinal lining, helping to better regulate our health and metabolism.
Meanwhile, cutting back on overall food intake can also increase life expectancy, especially when combined with early meals and fasting before eating the next day, experts say.
Rafael de Cabo, of the National Institute on Aging in Baltimore, who was not involved in the study, said: “There is emerging evidence that mild caloric restriction, 10 to 20 percent, along with prolonged fasting periods, of 12 hours or more, appears to provide health benefits Most research would support skipping the last meal of the day. [rather than breakfast, if a meal is to be skipped].”
“If you’re restricting your calories but not eating at the right times, you’re not getting the full benefit of calorie restriction.”
In the context of the cost-of-living crisis, reducing food consumption has an additional financial benefit, he said.
“By reducing your total food intake, you could save money, but it also helps to fast for an extended period of time without cutting calories,” he said.
In the longer term, Professor Takahashi hopes that learning more about the body’s internal clocks will help scientists find new ways to prolong healthy life in humans. That could happen through changes in the content or timing of meals or through medications that mimic the effects of those diets.
For now, he’s learning a lesson from his mice and restricting their feeding to a 12-hour window during the day.
