Healthy Nutrition: Does When You Eat Matter?

The saying “you are what you eat” contains more than a grain of truth. Nutritional science has shown how food influences not only our bodies but our brains as well.  Diets high in sugar and processed foods can lead to inflammation, which raises the risk of chronic disease. And low-fiber diets, too much alcohol and red meat can throw our gut microbiome off balance, affecting everything from our immune system to our mood.

Now, a growing body of research backs another truism:

When you eat may be as important as what you eat.

A recent study of overweight and obese patients showed that adapting a diet to a person’s chronotype – the internal clock that determines if someone is a morning lark or a night owl—was better at promoting weight loss and improving metabolic health and gut microbiota than a low-calorie diet.

What does that mean? “It’s about adjusting your intake of calories to be consumed when your brain and body are most active,” says Eytan Stern, MS, RD, LD/N, CNSC, a clinical dietitian for the University of Miami Health System. “If you’re a morning person, you should be eating most of your calories in the early part of the day.”  A night person, on the other hand, should do the reverse.

In practical terms:

• A person who is more alert first thing in the day should consume most of their calories in a substantial breakfast and lunch, followed by a lighter dinner.
• Those who are more active at night should eat a lighter breakfast, followed by bigger meals at the tail end of the day.

Researchers distributed caloric intake in this manner:

Morning chronotypes ate about 80% of their daily energy intake in the earlier part of the day through lunch. Evening chronotypes consumed the majority in the later part, starting with lunch. All 140 participants followed the principles of the Mediterranean diet, with daily calorie content adjusted for gender and starting weight.

While both groups lost weight, the evening people lost slightly more. The two groups also lost more weight than the control participants, whose caloric intake was not determined by their chronotype. In addition, researchers found that chronotype-adapted eating was better at changing body composition and improving cardiometabolic health and gut microbiome health.

Even if your goal is not weight loss, a person can take advantage of chrono-eating by adjusting their eating patterns to match the body’s natural sleep-wake cycle. The idea is to focus on the timing of meals, rather than restricting calorie intake or imposing fasting periods.

Stern calls the results “promising,” primarily because the eating schedule is easy to remember and simple to follow. 

“I’m very much about behavior change,” he says. “I want people to apply [research] information that can be sustainable over a long period of time. You get the most benefit by taking one small step at a time.”

There’s also a certain logic to the conclusions. If you’re using more body and brain power in the morning [or the evening], “you need more calories at that time to fuel” those activities.

However, Stern adds, modern-day schedules don’t always accommodate chronotype eating. Most people work 9-to-5 jobs, or a semblance thereof, so it might be easier to skip breakfast to get to the office on time and then pack the calories at home with dinner. Night chronotypes may have it worse, as they’re forced to work and eat when their bodies might prefer to be sleeping.  

Stern has other suggestions, both for weight loss or maintenance, and keeping your gut microbiome healthy:

• Avoid processed foods and aim for a regimen high in fruits, vegetables, whole grains, nuts and seeds. What we eat is still important.
• Practice mindful eating. Forget scrolling through email or watching the news during your meals. Focus on how your food looks and tastes. “When we’re distracted, we miss our body signal that says we’re full,” he explains. In other words, we tend to overeat when we’re not paying attention.
• Don’t skip meals. It usually leads to overeating. “Listen to your body,” Stern says. “If you’re hungry and ignore it, the hunger will come back tenfold, and that’s when we lose control of what and how much we eat.”
• Find fun and interesting ways to slip in more veggies and fruits during meals and snacks.
• Forget eliminating the foods you like and think moderation instead. “Over-restriction usually doesn’t work,” he says.

Written by Ana Veciana-Suárez, a regular contributor to the University of Miami Health System. She is an acclaimed author and journalist who has worked for The Miami Herald, The Miami News, and The Palm Beach Post.

Tags: Chrononutrition, Gut microbiome balance, healthy eating, Meal timing, Mindful eating techniques