Circadian-Aligned Fasting for Weight Loss
Any type of fasting is great for weight loss—but according to a recent study, eating in the morning and fasting at night could help you lose even more weight.
In a 2023 literature review, researchers looked at data from 30 different fasting studies. They wanted to find out whether meal timing during a fast changed how people lost weight.
The results were surprisingly clear: people who did “circadian-aligned fasting”—eating in the morning and fasting at night—had significantly greater weight loss and saw boosts to other fasting benefits as well.
Here’s a closer look at the study, and at how you can change your eating window to lose even more weight with fasting.
Does Eating at Night Cause Weight Gain?
You may have heard that eating before bed can cause you to gain weight. It turns out there’s some truth to that idea.
One problem is that people tend to overeat late at night. You’ve used up a lot of your willpower during the day, which means it’s harder to make good food choices when you go for a midnight snack. A 2014 study found that people who eat a lot in the evening tend to choose unhealthy food and eat a lot of it.
But it’s not just your willpower that matters in late-night eating. It turns out your circadian rhythm—your body’s internal clock—affects your metabolism, and eating late at night can have biological consequences that slow down weight loss.
A 2021 review found that leptin, your body’s fullness hormone, is disrupted in the evening. Leptin makes you feel satisfied by the food you eat—but when you eat later in the day or at night, you don’t release as much leptin after a meal, which primes you to overeat.
The same review also found that when you eat before bed, your body is less efficient at converting the food into energy. You metabolize protein and carbs more slowly in the evening, which means you’re more likely to store them as fat if you eat at night.
Basically, eating earlier in the day can help you maintain a stable body weight. But what if you combine early eating with fasting?
Lose Weight Faster with Circadian-Aligned Fasting
In a recent 2023 review, researchers looked at 30 different intermittent fasting studies, to figure out whether meal timing during your fast matters for weight loss. The researchers discovered a significant difference between weight loss in people who ate most of their food at night, versus eating most of their food in the morning.
The study noted three benefits to eating earlier in the day:
- Faster weight loss. People who ate most of their calories in the morning or at lunch lost significantly more weight, and lost it faster.
- Greater thermogenesis. Daytime eating led to greater diet-induced thermogenesis, which is when you burn more calories digesting your food, speeding up your overall metabolism.
- More stable blood sugar. Eating earlier in the day led to better glycemic control and more stable blood sugar and insulin levels.
The authors concluded by presenting the idea of “circadian-aligned fasting”—fasting where your feeding window is earlier in the day, giving you additional benefits and more weight loss.
However, they also noted that all types of fasting led to significant health benefits, and that whatever fasting schedule you find sustainable is the best option for you.
How to Start Fasting Today
Fasting is an amazing tool for fat loss and overall health. It will give you more energy, enhance your mental focus and clarity, slow down aging, and help you reach your weight goals faster.
Best of all, fasting is free, and you can start it right now. My Beginner’s Guide to Fasting will walk you through everything you need to begin fasting today.
If you want to take control of your health and feel better than you have in years, give intermittent fasting a try—you’ll be amazed by how good it makes you feel.