Dinner after 5 PM? Here’s why it’s riskier than you think for your glucose levels

For ages, grandma’s advice has echoed in dining rooms worldwide: “Eat early and light for dinner — it’s healthier!” Now, a cutting-edge study has given this age-old wisdom a firm scientific stamp of approval.

Published recently, the research reveals a startling fact: consuming over 45% of your daily calorie intake after 5 PM messes with glucose levels in your body. The findings indicate this can lead to type 2 diabetes, cardiovascular damage, and chronic inflammation.

The problem with late eating

“Maintaining high levels of glucose over long periods of time can have implications including a higher risk of progressing to type 2 diabetes,” explains lead researcher Dr. Diana Díaz Rizzolo.

While most people previously associated late-night feasts with weight gain (thank you, midnight pizza cravings!), this study points to a new villain: disrupted glucose metabolism. And here’s the kicker: it doesn’t matter how healthy you think your dinner is. Eating it late could still wreak havoc on your system.

Early birds vs. night owls

The study monitored 26 participants aged 50 to 70, all of whom were overweight or had prediabetes or type 2 diabetes. Divided into two groups — early eaters (those who ate most calories before evening) and late eaters (those who devoured 45% or more of their daily calories after 5 PM) — the participants logged their meals in real time using a mobile app.

Here’s the catch: both groups consumed the same number of calories and foods. Yet, late eaters consistently showed poorer glucose tolerance. They also tended to load up on carbs and fats as the day wound down, a dietary choice that’s especially problematic at night.

Díaz Rizzolo breaks it down: “The body’s ability to metabolize glucose is limited at night because the secretion of insulin is reduced, and our cells’ sensitivity to this hormone declines due to the circadian rhythm.” Essentially, your body’s natural “clock” isn’t set up to handle big meals when the sun goes down.

Timing is everything

This study flips the script on how we think about food and health. “Until now, personal decisions in nutrition have been based on two main questions: how much we eat, and what foods to choose,” says Díaz Rizzolo. “With this study, a new factor in cardiometabolic health is beginning to become increasingly important: when we eat.”

Her advice? Embrace the daylight! Make breakfast and lunch your calorie heavyweights, and keep dinner light and early. Want to up your health game? Avoid ultra-processed foods, fast food, and carb-heavy treats in the evening altogether. As Dr. Díaz Rizzolo wisely suggests, “The highest levels of calorie intake during the day should be at breakfast and lunch, instead of at teatime and dinner.”

While more studies are needed to solidify these findings, the message is clear: tune into your inner clock, eat with the sun, and let your metabolism thrive. Your health isn’t just what you eat — it’s when you eat it.

The findings of this research have been published in Nutrition & Diabetes.