A Harvard-trained doctor has revealed eight things he does every morning to look after his gut health in a viral Instagram post.

Dr Saurabh Sethi, a gastroenterologist, from California in the US, regularly shares advice to his more than 1.3 million followers on the platform.

In the recent clip, which has amassed 1,469 likes, he revealed things he does that he'd recommend others start doing too.

The first thing he does, he says is 'drink water before coffee' because it 'rehydrates after sleep and kick-starts digestion'.

Getting morning sunlight in the first hour of waking, is the second thing he does, which he wrote, 'resets your body clock and boosts serotonin for better digestion.' 

The body clock, also known as circadian rhythm, is the internal system that regulates sleep, temperature and hormone release.

Previously a study found daylight in the morning led to an improvement in circadian rhythms of cortisol a stress hormone released when the body's in 'fight-or-flight'.

Other research has shown higher cortisol levels causes inflammation which can cause gut problems like irritable bowel syndrome.

Dr Sethi also does 'two to three minutes of deep belly breathing before breakfast' which he explained 'activates the vagus nerve and calms the gut-brain axis'.

The vagus nerve sends signals from the gut to the brain, and the gut-brain axis is the connection between the two. 

While he didn't specify what type of deep breathing he does, it typically involves slowly expanding your abdomen rather than your chest when inhaling. 

The fourth habit he hailed is eating foods that contain prebiotics like slightly green bananas and oats for breakfast.

Prebiotics are compounds found in foods that help healthy bacteria grow in your gut microbiome.

A healthy gut microbiome has the right types of bacteria thriving together to support digestion, the immune system and even mental health.

Green bananas are rich in starch and pectin, two types of fibre that act as prebiotics, helping promote a health gut microbiome.

The fifth thing he does is include 'protein and fibre' in his breakfast, which 'balances blood sugar and fuels gut microbiome'.

He does this by eating 'Greek yogurt with berries, chia or flax' and 'eggs with veggies and kefir/lassi drink'. 

Kefir, a type of milk and lassi, a type of yoghurt, are both fermented drinks that contain probiotics which are good for your gut.

His sixth habit is to 'eat without screens' which he says he does because 'eating activates the parasympathetic system and scrolling triggers the sympathetic system'.

The parasympathetic system, is behind what is known as 'rest-and-digest', which calms the body down to allow digestion.

Meanwhile, the sympathetic system is responsible for the 'fight or flight response' which can be triggered by screens.

According to the NHS these are two different branches of the nervous system, so we cannot be in both at the same time.

Previously Chinese researchers also found screen use while eating lowers intuitive eating—the process of listening to your body's cues like hunger and fullness.

Meanwhile, he also takes a walk after breakfast each morning 'to help aid digestion and reduce post-meal bloating'—It 'makes makes a difference', said Dr Sethi.

Dr Sethi also checks his stool each day, looking at 'colour, shape and ease', he explained.

He uses the Bristol Stool Chart, which classifies stools into seven types depending on form and consistency, to assess bowel movements.

The chart, which can be found online was developed in the UK by NHS medics in order to help doctors identify digestive or bowel issues. 

Type one refers to hard difficult refers to hard, difficult to pass stools, while type seven to liquid or watery bowel movements. 

'Aim for Bristol three to four,' advises Dr Sethi.

As a final tip, he suggests picking two to three of these daily habits to start with before adding more in over time.

Just last month, in another post, Dr Sethi urged people to spend less time on the toilet to avoid a painful health condition. 

He explained: 'Extra sitting time increases pressure on the rectal veins, which means higher risk of haemorrhoids—so keep it to less than five minutes.'

This unfortunate complication, also known as piles, is when lumps grow inside and around the anus and rectum.

However, many social media users commenting on the video ironically said they were watching it while on the toilet.

One user wrote, 'I scrolled to this vid while on the loo', followed by laughing emojis, while another wrote 'me watching this in the washroom'.

But it's no laughing matter—earlier this month a study confirmed that using a smartphone on the toilet can almost double your chance of haemorrhoids.