- Eating more than 45% of daily calorie intake after 5 p.m. may contribute to higher blood glucose (sugar) levels in older adults with prediabetes or early type 2 diabetes, a recent study suggests.
- Poorly regulated blood sugar levels can contribute to type 2 diabetes development, greater cardiovascular risk, and chronic inflammation.
- Experts say that metabolic and hormonal factors make it important to eat the lightest meal of the day as a dinner: fewer carbohydrates, more healthy fats and protein, and no desserts.
- Consistent, quality sleep will also go a long way toward balancing appetite and glucose metabolism, experts say.
As the holidays approach and the epic meals begin, a study recently published in
The study, conducted by teams from the Universitat Oberta de Catalunya in Barcelona, Spain, and from Columbia University, NY, suggests that eating more than 45% of daily calorie intake after 5 p.m. may be linked to poorer glucose tolerance, particularly in older adults with prediabetes or early type 2 diabetes.
This can significantly harm health over time, leading to a greater risk of type 2 diabetes development, greater cardiovascular risk, and chronic inflammation.
The previously assumed consequence of late eating was primarily weight gain due to a slower metabolism as we wind down and our bodies prepare for and engage in sleep.
The new study suggests that, regardless of a person’s weight or general caloric intake, the time of day when they eat can have significant consequences on glucose metabolism.
The study classified 26 participants between the ages of 50 and 75 — who had overweight or obesity, as well as prediabetes or type 2 diabetes — into two groups: “early eaters” who consumed most of their daily calories before 5 p.m., and “late eaters” who ate 45% or more of their calories after 5 p.m. for 14 days.
The groups ate a comparable amount of daily calories and macronutrients. However, late eaters consumed almost double the number of calories after 5 p.m., consuming more fat and carbohydrates overall and trending toward higher protein and sugar intake than early eaters.
In oral glucose tolerance tests, the late eaters had notably higher blood glucose levels after 30 and 60 minutes, indicating a lower tolerance of glucose (sugar).
This trend was maintained regardless of participants’ body weight and fat mass, calorie intake, and diet composition.
Nate Wood, MD, an instructor of medicine and the director of culinary medicine at the Yale School of Medicine, who was not involved in the study, explained to Medical News Today that eating later in the day or into the night does have the capacity to add weight to the body due to the simple fact that most people are much less active at night, and not active at all as they sleep.
“The issue with eating late at night, we think, is that we are consuming calories at a time when our body doesn’t need them,” Wood told us.
He illustrated this by saying:
“Imagine you eat a few slices of pizza and then immediately go to bed. We break down that food into energy (calories), but then we have no immediate use for that energy because we’re sleeping, not exercising! So, what does our body do with that energy? It stores it to use later, when we need it. And how does our body store energy? As fat! This is one reason that it’s generally recommended to try eating earlier in the day as opposed to later.”
Pouya Shafipour, MD, a board-certified family and obesity medicine physician at Providence Saint John’s Health Center in Santa Monica, CA, who was not involved in the study, explained that the body is much more insulin-resistant at night, due to circadian rhythms.
During the day, there is more insulin secretion and increased pancreatic activity, he explained.
“When the receptors at the back of the retina sense that light is going down, melatonin starts getting secreted from the pituitary gland, and then that suppresses the pancreas,” Shafipour said, adding that eating late can be very harmful in the long and short term.
“If you’re a night owl and you’re just eating late, higher chance of insulin resistance, basically, based on your genetic predisposition. Higher rate of pre-diabetes, diabetes development, things like that. And this is something that we typically see with graveyard shift people, you know, firefighters, cops, doctors, medical staff that work at night a lot,” he pointed out.
It is probably not the most popular answer during the holidays, but dinner should ultimately be the lightest meal you eat, Shafipour advised.
This means fewer carbohydrates — so avoiding pasta, mashed potatoes, rice — and indulging less in dessert and alcohol.
“You want your dinner or the latest meal to be the lowest carbohydrate and simple carbohydrate meal,” Shafipour explained. “So you know this would be something with some Healthy sources of protein and some Healthy sources of fat, and maybe a salad. So optimally, you want to avoid desserts, alcohol, any type of refined sugar, white rice, white bread, potatoes, even a lot of fruits, because fruits also have sugar fructose.”
Because of insulin resistance, he added, there is a daytime window where those larger-carbohydrate meals can work with your metabolism.
“The most active time in terms of metabolism is plus and minus an hour between probably about 10 a.m. to 4 or 5 p.m.,” Shafipour said.
“So if one wants to optimize their insulin sensitivity, [they] want to eat [their] heavier carbohydrate meals in that window and then try to wind it down by sundown and have a lighter dinner. And the lighter dinner will help with insulin sensitivity, will provide a better quality sleep,” he noted.
The balance between sleep and eating is important to strike for metabolism and overall Health. Because sleep is so important, Wood said that a consistent pattern each night was the most important factor.
“Most adults need 7 to 8 hours of sleep per night. Getting less than that or more than that can have negative effects on our Health,” Wood pointed out.
“I recommend patients try to go to bed at the same time every night. This means that if you go to bed at 10 p.m. on weeknights, try to go to bed no later than 10:30 or 11:00 p.m. on weekends. The more consistent we can keep our sleep schedule, the better,” he advised.
Shafipour explained that the hormonal changes that occur during sleep have a significant effect on appetite throughout the day:
“Sleep is also by itself very important, because we have the hormone leptin, which is an appetite suppressing hormone, get secreted, and it peaks around 6 or 6 and a half hours of sleep. So optimal sleep schedule would be for an average adult would be between 7 to 8 hours so you get enough leptin and ghrelin, which is the appetite hormone that one also doesn’t stay up too much during the day. So if we sleep less than 6 and a half hours, we’ll notice that we’re hungrier during the day looking for food more.”
