The Ideal Time to Eat
It’s not only the speed at which individuals eat that may influence outcomes but when they take their meals. Research indicates that eating earlier in the day to align meals with the body’s circadian rhythms in metabolism offers health benefits.
“The focus would be to eat a meal that syncs during those daytime hours,” Collin Popp, PhD, MS, RD, a research scientist at the NYU Grossman School of Medicine in New York, told this news organization. “I typically suggest patients have their largest meal in the morning, whether that’s a large or medium-sized breakfast, or a big lunch.”
A recent cross-sectional study of 2050 participants found that having the largest meal at lunch protected against obesity (odds ratio [OR], 0.71), whereas having it at dinner increased the risk for obesity (OR, 1.67) and led to higher body mass index.
Consuming the majority of calories in meals earlier in the day may have metabolic health benefits, as well.
A 2015 randomized controlled trial involving 18 adults with obesity and T2D found that eating a high-energy breakfast and a low-energy dinner leads to reduced hyperglycemia throughout the day compared with eating a low-energy breakfast and a high-energy dinner.
Time-restricted eating (TRE), a form of intermittent fasting, also can improve metabolic health depending on the time of day.
A 2023 meta-analysis found that TRE was more effective at reducing fasting glucose levels in participants who were overweight and obese if done earlier rather than later in the day. Similarly, a 2022 study involving 82 healthy patients without diabetes or obesity found that early TRE was more effective than mid-day TRE at improving insulin sensitivity and that it improved fasting glucose and reduced total body mass and adiposity, while mid-day TRE did not.
A study that analyzed the effects of TRE in eight adult men with overweight and prediabetes found “better insulin resistance when the window of food consumption was earlier in the day,» noted endocrinologist Beverly Tchang, MD, an assistant professor of clinical medicine at Weill Cornell Medicine with a focus on obesity medication.
Patients May Benefit From Behavioral Interventions
Patients potentially negatively affected by eating too quickly or at late hours may benefit from adopting behavioral interventions to address these tendencies. To determine if a patient is a candidate for such interventions, Dr. Popp recommends starting with a simple conversation.
“When I first meet patients, I always ask them to describe to me a typical day for how they eat — when they’re eating, what they’re eating, the food quality, who are they with — to see if there’s social aspects to it. Then try and make the recommendations based on that,” said Dr. Popp, whose work focuses on biobehavioral interventions for the treatment and prevention of obesity, T2D, and other cardiometabolic outcomes.
Dr. Tchang said she encourages her patients to be mindful of hunger and fullness cues.
“Eat if you’re hungry; don’t force yourself to eat if you’re not hungry,” she said. “If you’re not sure whether you’re hungry or not, speak to a doctor because this points to an abnormality in your appetite-regulation system, which can be helped with GLP-1 [glucagon-like peptide 1] receptor agonists.”
Adjusting what patients eat can help them improve their meal timing.
“For example, we know that a high-fiber diet or a diet that has a large amount of fat in it tends to empty from the stomach slower,” Dr. Camilleri said. “That might give a sensation of fullness that lasts longer and that might prevent, for instance, the ingestion of the next meal.”
Those trying to eat more slowly are advised to seek out foods that are hard in texture and minimally processed.
A study involving 50 patients with healthy weights found that hard foods are consumed more slowly than soft foods and that energy intake is lowest with hard, minimally processed foods. Combining hard-textured foods with explicit instructions to reduce eating speed has also been shown to be an effective strategy. For those inclined to seek out technology-based solution, evidence suggests that a self-monitoring wearable device can slow the eating rate.
Although the evidence is mounting that the timing and duration of meals have an impact on certain chronic diseases, clinicians should remember that these two factors are far from the most important contributors, Dr. Popp said.
“We also have to consider total caloric intake, food quality, sleep, alcohol use, smoking, and physical activity,” he said. “Meal timing should be considered as under the umbrella of health that is important for a lot of folks.”
A version of this article appeared on Medscape.com.