Candlelit Dinners: Fitness Friend or Foe?

Timing meals later at night can cause weight gain and impair fat metabolism.

There’s nothing like a nice family dinner, sitting around the table and enjoying time laughing, talking, and being in each other’s company. Dinner is probably the most important meal for the average American family, as it’s the only time everyone is home from school and work.

Unfortunately, dinner could be doing you a lot more harm than good. According to a recent study from the University of Pennsylvania School of Medicine, late-night meals can lead to some negative physical changes: higher insulin, cholesterol, and weight levels, reduced fat metabolism, and an increase in endocrine markers that play a role in diabetes, cardiovascular disease, and other health problems. Sounds pretty scary, right? We definitely, need to sit up and take notice.

The study put nine healthy adults through eight weeks each of two different eating schedules: 8 AM to 7 PM, and noon to 11 PM. As expected, the results were visibly different with the schedule of eating later. Not only did the adults gain more weight, but the respiratory quotient (more carbon dioxide produced by the body as a result of macronutrient metabolism) also increased. This indicated that the body was digesting more carbs but fewer fats. Blood tests revealed that the later eating schedule also raised fasting glucose, cholesterol, insulin, and triglycerides.

Endocrine panels revealed that the hunger hormone ghrelin was produced in larger quantities earlier in the day, while the satiety hormone leptin was produced later in the day. This is indicative of your body’s preferred eating rhythms: more food earlier on, and less food later on.

It turns out you need to worry about more than just how much you’re eating; you’ve also got to think about when you eat. Your body naturally releases more hunger hormones early in the day, so that’s when you should be doing most of your eating. This is the proof that breakfast is the most important meal.

“While lifestyle change is never easy, these findings suggest that eating earlier in the day may be worth the effort to help prevent these detrimental chronic health effects,” said Kelly Allison, PhD, an associate professor of psychology in Psychiatry and director of the Center for Weight and Eating Disorders, and senior author on the study. “We have an extensive knowledge of how overeating affects health and body weight, but now we have a better understanding of how our body processes foods at different times of day over a long period of time.”

Similar yet much shorter previous studies have suggested similar results, but this is the first long-term study looking at the timing of eating patterns that also controlled for sleep-wake cycles, exercise, macronutrient intake, etc. to pinpoint the effects of prolonged eating at different times of the day.


1. Christina Hopkins, et al. “Timing meals later at night can cause weight gain and impair fat metabolism: Findings provide first experimental evidence of prolonged delayed eating versus daytime eating, showing that delayed eating can also raise insulin, fasting glucose, cholesterol, and triglyceride levels.” the University of Pennsylvania School of Medicine, 2 June 2017.