They say the way to a woman's heart is through her stomach.
It's the same for weight loss - you'll unlock the door to great health by finding out what's going on in your belly.
And, if you're feeling brave, it could be enormously beneficial to have what eventually comes out of your tummy - your poo - scientifically analysyed.
Before you pooh pooh this controversial technique, let's look at the science, as it's all about bringing balance and harmony to the chemistry of your gut.
You can carry around 2kg of microbes in your gut and intestine.
This microbiome - or population of bacteria - influences your health in a massive way, with two thirds of it entirely unique to you, either because of your genes or what you put into your body.
If your stomach and small intestine are struggling to digest a certain food, your gut microbes step in to help and ensure we get the nutrients we need while also aiding the production of vitamins like B and K.
All this is vital for your immune system.
If you don't have a broad variety of bacteria in your gut, you're likely to be more sensitive to certain foods, like egg, milk or peanuts.
Meanwhile if you have too much of a specific bacteria it can also impact on your health.
There are some studies that suggest a bacteria strain called 'Christensenellaceae minuta' can reduce or prevent obesity by improving digestion.
Whereas a lack of bacteria in the large intestine has been shown to drive obesity by slowing down the activity of brown fat, which protects against weight gain when stimulated by burning calories and white fat.
If you have a stool sample analysed, you'll get a detailed breakdown of this gut bacteria.
Then you can use this information to find out which foods you need to be consuming in order for you to bring everything back into a balance.
In severe cases, where someone is quite sick, you can give them very effective prebiotics or probiotics in order to achieve results.
We're talking about very specific strains - unlike most of the supermarket yoghurt drinks which are entirely ineffective - which are proven to work.
And, what's important for yo-yo dieters, is that it can be vital in kick-starting someone's health plan.
For example, having poor gut bacteria make-up can lead to massive cravings for sweet and sugary food, which can obviously hinder any attempts to lose weight.
And the gut and the brain are also inextricably linked.
Gut bacteria produce many of the neurochemicals responsible for regulating mental processes, so if yours are out of kilter you can end up with depression an anxiety - another major cause of weight gain.
Meanwhile a general feeling of lethargy because you're not digesting food properly will make you feel like you don't want to do any exercise too.
All this means that it's easy to get trapped in a vicious circle - all because of what's going on in your gut!