We have been told for decades that a calorie is a calorie and as long as we eat less of it than we burn, we will certainly lose weight.
However, it seems more and more that when it comes to staying healthy, not only what you eat is important, but also when you eat.
This can all have to do with our circadian rhythms. These 24-hour cycles control everything from when we feel sleepy to when our immune cells are most active, allowing our bodies to prepare for regular events – including the arrival of food.
It seems that when it comes to staying healthy, not only what you eat is important, but also when you eat (file image)
They also help our organs and tissues to change tasks and recover when they are least likely to be active.
Our digestive system is no exception. We produce less saliva at night; our stomach produces less digestive juices; slow the intestinal contractions moving food through our intestines; and we are less sensitive to the hormone insulin, which sucks up glucose from our bloodstream so that it can penetrate our cells and be used as fuel.
This all makes sense: for most of human history, eating was done during the day and at night it was for sleeping. So our bodies are set to process food more efficiently during the day.
The invention of electric light has made it much easier to stay up late and eat long after sunset, with potentially negative consequences for our health (file image)
“We are determined to go through this daily cycle,” says Professor Satchin Panda, who is researching circadian rhythms at the Salk Institute in California.
However, the invention of electric light has made it much easier to stay up late and eat long after sunset, with potentially negative consequences for our health.
Research recently presented at an American Heart Association conference, for example, found that the more a woman ate after 6 p.m., the worse her heart health was, with a greater risk of higher blood pressure and body mass index, and poorer control of long-term blood sugar. Other studies have shown that people who eat late have a higher risk of obesity and type 2 diabetes.
The results of animal studies into squeezing the window when eating food are attractive.
In one, Professor Panda fed two groups of mice the same high-fat, sugar-free diet – the only difference was that one group had access to food 24/7 and the other could only eat during an eight-hour window during their “daytime”.
The first group arrived and began to develop high cholesterol and type 2 diabetes, while the group on a limited-time diet remained relatively lean and healthy – despite consuming the same number of calories.
Remarkably, time-bound eating was even able to reverse type 2 diabetes in mice.
Preliminary research suggests that meal timing can also be important for human health, with studies showing that those who eat an hour before bedtime have lower blood sugar levels than those who dine earlier, and that dieters who consume the majority of their calories before 15:00 lose around 25 percent more weight than those who party later.
However, researchers say it is too early to give detailed advice about meal times.
First, we do not yet understand why late or extended food can be bad for us.
Nutritionists at the University of Aberdeen are investigating whether consuming a full breakfast is beneficial for weight loss and whether it changes the way people metabolize food compared to consuming a larger proportion of their calories later in the day.
Professor Panda believes that the reason that time-bound eating is better for our health is because it gives our intestines more chance to recover and to recover.
Up to a tenth of the cells along our intestines are damaged every day by normal digestion and eating a late evening meal followed by an early breakfast leaves very little time for possible repairs.
“Just as we cannot repair a road when there is traffic, it is difficult to repair our guts when there is food in our stomach,” says Professor Panda.
Ultimately, the barrier between the inside of the intestine and the rest of the body can become “leaked”, causing allergy-causing chemicals and bacteria to get through, increasing general levels of inflammation in the body and causing poor health, he adds.
It can also be important to keep your meals regularly, no matter what time you eat.
This is because eating at unexpected moments can change the timing of the “clocks” in our digestive tissue, making them synchronized with clocks elsewhere in our body and making our metabolisms less efficient.
For example, last month’s research suggests that having breakfast later in the weekend than you do during the week leads to weight gain.
“The general advice is to have regular meal patterns and allow your body periods of non-consumption or fasting,” says Dr. Gerda Pot, guest lecturer in nutrition studies at King’s College London.
“Maybe it would come back to a pattern of three meals a day without snacks, like our grandparents and great-grandparents, wouldn’t be so bad.”