“Don’t eat after 7pm”, “Close the kitchen after dinner”. This advice is repeated so often (usually directed at people trying to lose weight or avoid weight gain) that it takes on a veneer of truth and common sense.
Even among my patients who have left the pursuit of weight loss behind (or are working on it), the idea of avoiding dinner or nighttime food is often so ingrained that they won’t eat at that time even if there are good reasons to:
- They are a healthcare provider in a hospital (where it’s generally hard to find time and space allowed to eat) and they don’t get off shift until 7pm.
- They have a food allergy or severe food intolerance (coeliac, lactose intolerance) and went to someone’s house for dinner only to find they couldn’t eat.
- They find it difficult to eat enough and the evening is a time when they feel more able to eat.
But back to the original “rule”: is it true that eating at night causes weight gain?
You are not a mouse
More than a decade ago, a study found that eating at night leads to significant weight gain, compared to eating during the day — but that study was done on mice, and you’re not a mouse. Research on humans is a bit more nuanced.
For example, a 2023 study randomly assigned 16 people with a body mass index (BMI) in the “overweight” or “obese” range to either eat their meals earlier in the day (8 a.m., noon, and 4 p.m.) or later in the day (noon, 4 p.m., and 8 p.m.) during a six-day laboratory stay.
Several weeks later they returned to the lab to consume the same number of calories, but on the opposite schedule. The researchers found that when participants ate later in the day, they tended to feel hungrier and have lower levels of leptin – a hormone that makes you feel full. They also burned fewer calories during the day. Yes, together, that could lead to weight gain.
The role of circadian rhythms
Now, there are some good reasons to limit or avoid eating at night. For example, eating too close to bedtime can cause heartburn or acid reflux. Also evolving research strongly suggests that eating at the “wrong” time of day causes a misalignment in our circadian rhythms or internal clockswhich can increase the risk, yes, for weight gain, but more worryingly for cardiovascular disease, diabetes and other health conditions. Our bodies are designed to eat and be active during the day and fast and rest at night.
Because of this design, our bodies use calories and carbohydrates (energy!) more efficiently earlier in the day, which helps support metabolic health. So, while eating in the evening can disrupt circadian rhythms, so can skipping breakfast.And I have many clients who skip breakfast because they “just aren’t hungry.”
(As I explain, they’re just not hungry because their bodies have stopped sending them hunger signals in the morning, even though their bodies need fuel in the morning.)
A recent study that followed 48,150 adults without diabetes, heart disease or cancer for four years found that those who skipped breakfast and ate in the evening they gained slightly more weight – about half a kilo, big passion – than those who did nothing. Eating a low-quality diet made things worse, which is a reminder that While when we eat may matter, what and how much we eat also matters.
Ultimate food for thought
What can you do if your schedule means you have to eat a late dinner? From a health perspective, try to make this meal a smaller, lighter one with a higher protein than carbohydrate content, and make breakfast and lunch bigger.
(I know, I know, that might be a tough stretch with some people’s schedules, but it’s about doing the best you can.)
If you eat dinner at a “normal” time but want to eat more than a light snack later in the evening, explore whether you are eating enough during the day. If so, is your late night eating related to stress or emotional eating? Is it due to deeply ingrained habits like eating while watching TV?
If you find yourself frequently waking up multiple times to eat more than four nights a week, talk to your doctor, because this could be a sign of night eating syndrome, an eating disorder that is often combined with a sleep disorder.
Need more help making changes that support health and wellness? Click here to schedule a free 20-minute Discovery Call to talk about your concerns and whether you would benefit from nutritional therapy.
Disclaimer: All information provided here is general in nature and provided for educational purposes only. This information should not be taken as medical or other health advice related to an individual’s specific health or medical condition. You agree that use of this information is at your own risk.
Hi, I’m Carrie Dennett, MPH, RDN, a weight that includes registered dietitian, nutritionist and body image consultant. I help adults of all ages, shapes, sizes and genders who want to break free eating disorders, disordered eating or years of dieting. If you need to learn how to management of IBS symptoms with food, or improve your eating and lifestyle habits to help manage a current health concern or just supporting your overall health and wellness, helping people with that too.
Need 1-on-1 help with your nutrition, food or body image concerns? Schedule a free 20-minute Discovery Call let’s talk about how I can help you and explore if we’re a good fit! I am in network with Regence BCBS, FirstChoice Health and Providence Health Plan and can bill Blue Cross and/or Blue Shield insurance in many states. If I don’t get your insurance, I can help you claim compensation yourself. To learn more, explore our insurance and service areas page.
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