Written by Courtney McMahan, RD

As a dietitian, one of the questions I get asked most frequently is “will eating at night make me gain/prevent me from losing weight?” Conventional wisdom has long held that eating at night will expand your waistline and hurt your weight loss efforts, while many healthcare professionals insist that calories in, calories out is the gold standard, end-all be-all for weight loss. So which is right? Well, as with most questions in nutrition, the answer lies somewhere in the middle.

The Basics

It’s long been known that a caloric deficit is required for weight loss. The staunch adherence to the calories in calories out model typically only focuses on two things: eat less and move more. However, this discounts the numerous other factors that influence this energy balance equation: hormones that regulate appetite, types of food consumed, hormonal issues like insulin resistance and PCOS, psychological factors, sleep quality, and genetic factors. 

What Research says

Some research has shown that night time eaters do tend to be at an increased risk for weight gain. While the mechanism for this is not well understood, there are a few theories for what causes this. Nighttime eating can often cause overeating due to waiting too long to eat. When you wait too long to eat, you are more likely to eat past the point of fullness. Eating too much in the evening can also cause sleep disruptions, which can cause negative impacts on metabolism. Another study found that nighttime eaters had poorer metabolic profiles such as elevated insulin, fasting glucose, cholesterol, and triglycerides. It also found that the hormone ghrelin (appetite stimulating hormone) peaked later in those who ate later in the day; meaning, eating later in the day causes appetite to be stimulated more in the evening. 

Midnight Snacks or Midnight Madness?

While calories in calories out is still the most important factor in terms of weight loss, evidence is accumulating that consistently eating later in the day may lead to over consumption of calories and to unfavorable metabolic changes that may make weight gain more likely. 

Final Thoughts

In short, occasionally having a late night snack or an 8pm dinner won’t cause your weight to shoot up or lead to negative metabolic changes. But if you find yourself rummaging through the cabinets on a nightly basis, it might be time to restructure your daily meal schedule. Start by slowly adding calories to your more active hours of the day: begin eating a small breakfast if you usually skip it, add an extra 200 calorie snack between breakfast and lunch, reduce your calories at dinner by having a snack a few hours before. Your body can handle a day or two of unusual eating, but our daily habits can have lasting impacts on our metabolic health.