Eating with our Circadian Rhythms
For those of you that are not convinced by the Chinese clock telling you to eat breakfast between 8-10am here is some more biology for you:
In the morning:
The intestines spring into action digesting nutrients, moving waste along for the morning poop
The stomach is ready for a big meal so all the nerves in your stomach become less sensitive – this allows the stomach to comfortably expand, encouraging you to eat more.
In the morning your Cortisol levels (waking + stress hormone) are higher to make you feel more hungry and awake
Your insulin sensitivity is high so you can efficiently metabolise fats and sugars
This is all coordinated with Ghrelin – a hormone released from the stomach that triggers hunger and rises before anticipated meals
And Leptin another hormone released from our fat cells and crossing the blood brain barrier which controls our satiety (feeling of fullness) it suppresses appetite by rising after meals to keep you full until the next mealtime.
The liver increases in size in the day (producing digestive enzymes and bile – which emulsifies fat).
In the late afternoon/evening:
The stomach nerves sensitise to stretching (triggering the ‘I’m full’ feeling from less food) so you don’t eat as much at night.
The liver shrinks + the stomach and pancreas are quiet
High insulin levels + chronic sugar consumption in particular causes leptin resistance = you don’t know when you’ve had enough. Excess sugar consumption also disrupts Ghrelin. This pattern can lead to incorrect signals of hunger and feeling full and is a part of the reason why excess sugar consumption causes weight gain.
So:
Eat your biggest and most nutritious meal for breakfast (between 8-10am), and make it a hot breakfast
And as usual, avoid refined sugars and carbohydrates
Swap white for brown and simple for complex.
Try and eat that breakfast by a sunny window/outside - remember our circadian rhythms (the rise and fall of our hormones which dictate these things) are controlled by our exposure to natural light… In general try and open your blinds as soon as you wake up and get minimum 20-30 mins of natural light/sunshine – preferably outside (even if its cloudy)
Take breaks between meals (i.e. don’t snack all day - this also causes leptin resistance).
Don’t eat late at night (remember should be 3 hours no eating before bed - herbal teas are ok but nothing with ‘calories’ or caffeine/alcohol). This confuses the circadian rhythm too.