Yes, this statement is a bold one, but there is a lot of truth to it. And the truth, resides in your hormonal balance.
Whatever your reason is for staying up late with the lights on, using the computer, talking on the phone or watching TV hours after the sun has gone down fools your body into believing it is still daytime and stimulates your central nervous system. This results in an increase in the hormones, cortisol and insulin which makes you want to eat! And you aren't going to want to chow down on a grilled piece of salmon and veggie sticks.
Studies prove, you will crave carbohydrates and this leads to typical late-night snacking on cookies, chips, cereal - you name it, you probably eat it if you are a night owl.
As Dr. Natasha Turner explains in her book The Hormone Diet, our hormones are so very intimately connected to circadian rhythm and when we ignore the simple fact that night follows day and this means sleep, we mess up the rhythm which can lead to hormonal imbalance.
Why does eating late mean you gain weight, specifically body fat?
Excess carbs will increase the blood glucose levels and this excess will eventually convert to fat. Even if you do not snack, staying up late regularly causes cortisol to release a nightly dose of sugar into the bloodstream for energy, insulin then rises to store that sugar as fat. Constantly high levels of insulin are a a risk factor in developing insulin resistance and type 2 diabetes.
What time should you hit the sack?
Ideally well before midnight, by 10:30pm because it lowers your night-time cortisol and insulin levels, and raises your melatonin levels. Melatonin has incredible anti-cancer and anti-aging benefits. There is a lot of truth to the old saying "beauty sleep". I speak from personal experience. When I am burning the candle at both ends (as my mother would tell me!) I don't look as joyous. My skin doesn't glow and I look "haggard". lol. So, I make my best efforts to get to bed early.
Remember that it is key to sleep in complete darkness. Light disrupts the pineal gland in your brain that is responsible for releasing melatonin. If you often sleep in front of the TV or with the light on you may be missing out on very important cancer-fighting ability and your best anti-aging remedy - sleep.