All of us have trillions of different bacteria living in our guts and amazingly our precise bacterial mix is unique - like fingerprints, no two people's combinations of gut bacteria are exactly the same.

The different species of gut bacteria are essential for digestion and helping produce vitamins.

But it's increasingly clear that gut bacteria - known as the microbiome - influence your risk of many health problems, from heart disease and inflammatory bowel conditions to type 2 diabetes.

Professor Tim Spector, a leading expert and professor of genetic epidemiology, says you can tell more about a person from their stool than their DNA. The Mail tested the theory on seven volunteers including Zoe Budd, 30

They may even affect your mood and weight by controlling the amount of energy extracted from food and how much your blood sugar rises after eating.

'The diversity of microbes in our bodies is 30 per cent lower than it was 50 years ago, which may contribute to the obesity epidemic,' says Tim Spector, a leading expert and professor of genetic epidemiology at King's College London.

Scientists are still identifying which bacteria are beneficial and how to boost them. 'It's hoped that in future we may be able to manipulate gut bacteria to overcome illnesses, such as irritable bowel syndrome and even obesity,' says Professor Spector.

He heads the British Gut Project, created a year ago to build up a microbial profile of the population to better understand their effect on health.

This is being done by testing people's gut bacteria via a small faecal sample analysed in a lab in America. Volunteers pay £75 and receive a profile of their bacteria.

Professor Spector says you can tell more about a person from their stool than their DNA. 'While we share 99.9 per cent of our DNA with others, we only ever have about 10 to 20 per cent of our gut bacteria in common.'

Zoe Budd, 30, lives with her fiance Darren and their two children, aged seven and one, in Middlesex. Zoe tested positive for the 'lean microbe' christensenella

Our gut bacteria are partly inherited from our parents, but are strongly affected by diet, lifestyle and environment.

'You can alter your gut bacteria for better or worse in a matter of days through the lifestyle choices you make,' he says.

Dietary fibre, exercise and sleep boost the variety and number of 'good bugs'; junk food and antibiotics kill them off, allowing 'bad' bacteria to flourish.

To see how diet and behaviour can affect the microbiome, we asked five healthy people with very different lifestyles to take the British Gut Project test.

Professor Spector then analysed the results 'blind' - he knew nothing about our volunteers' lifestyles - and Good Health gave them a 'gut health' rating.

Our experiment revealed just how influential our bacteria really are and could make a difference to YOUR life, too...

SKINNY MICROBE DEFIES BAD DIET

Zoe Budd, 30, lives with her fiance Darren and their two children, aged seven and one, in Hillingdon, Middlesex. She is a therapist at a London medi-spa. She is 6 ft and 9 st 9 lb (Body Mass Index/BMI: 18, healthy).

I have the world's worst diet yet I'm effortlessly very slim. Today, I had three Walnut Whips for breakfast and I love croissants, bacon sandwiches, cookies and cakes.

I try to have a proper meal with vegetables with my children every day. But I always have pudding, such as chocolate cake with clotted cream. People always ask me where it all goes.

EXPERT VERDICT: What stands out in Zoe's sample is she's the only one with christensenella, the 'lean microbe', which only last year my lab found was linked to weight. It's so new we aren't sure how it works, but we know it protects against accumulating fat around the organs, which is linked to a raised risk of type 2 diabetes and cancer.

The 'lean microbe' is likely to be inherited, and you don't lose it over time. We don't know yet how easy it is to acquire, but we're working on it. It's been found to reduce weight gain when transplanted into mice, for example.

One in ten people has detectable christensenella and Zoe has 13 times the normal amount. She could sell these microbes!

The rest of Zoe's gut bacteria is a mixed picture and I suspect she possibly doesn't have a great overall diet. Most people's guts are dominated by two classes of bacteria, firmicutes and bacteroidetes, and her firmicutes are dominating.

They create chemicals that fuel our cells, enabling the body's systems to communicate with one another properly. An imbalance is a sign of poor diet and is normally associated with weight gain.

But Zoe has a reasonable profile of bacteroides and prevotella, bacteria that thrive on fibre. Eating a greater variety of vegetables could improve her balance.

GUT HEALTH RATING: 6/10

Zoe says: I'm excited to discover I have this amazing microbe, probably from my slim parents.

Sometimes I get too skinny and try to put on weight, but I don't think there's any point now as this microbe means it won't make much difference.

I can't be complacent about my health, though, so I will try to eat more fruit and vegetables.

RED WINE BOOSTS BACTERIA MIX

Tim Pearson, 61, is married and lives in Oxfordshire. He works in the wine trade, co-owning a vineyard. He is 6 ft and 13 st 2 lb (BMI: 24.9, healthy).

Tim Pearson, 61, is married and lives in Oxfordshire. Astonishingly Tim's profile contained 100 times the normal microbes, many African, and very rare in human guts. His profile looks more African than European

I eat well, starting with a smoothie of fruit, greens, nuts, seeds, organic yoghurt and coconut milk. For lunch, it's soup and wholemeal toast; dinner will be meat or fish with plenty of vegetables and potatoes. I drink a large glass of red or white wine five days a week, and maybe two glasses at the weekend, and enjoy the odd slice of cake. I don't have any health problems.

EXPERT VERDICT: Tim has very few firmicutes and bacteroidetes; 50 per cent of his bacteria are proteobacteria, which normally form less than 5 per cent and are associated with mild inflammation (and could suggest low-grade infection).

This bacteria is also linked to living in developing countries. Even more unusually he has 100 times the normal load of microbes, some from soil, many African, that are so rare in human guts we don't know what they do. In fact, his profile looks more African than European.

Malcolm Barbour, 44, a software developer, lives with his wife and two children, ten and 13, in Orpington, Kent. Malcolm has a strange and unbalanced looking microbiome

Overall, it's a fair mix. I'd be surprised if he was ill or fat. After my analysis, I learned Tim is a wine drinker. While you can't see this in individual bacteria, it may explain his reasonably healthy mix, as moderate amounts of alcohol boost bacterial diversity.

Red wine contains 100 chemicals that microbes feed off. Too much, however, makes microbes produce inflammatory toxins.

GUT HEALTH RATING: 6/10

Tim says: It's reassuring that my gut looks OK. I regularly visit South Africa for work and lived there for two years in the early Nineties so the African microbes must come from there. Professor Spector is right: I don't struggle with weight. I have a 34 in waist.

PASTA AND RICE TIP THE BALANCE

Malcolm Barbour, 44, a software developer, lives with his wife and two children, ten and 13, in Orpington, Kent. At 5 ft 10 in, he weighs 11 st 4 lb (BMI: 23, healthy).

I AM a keen marathon runner and train five days a week, running 50 miles in total. I might have porridge, toast and marmalade for breakfast, then grab a cheese or tuna sandwich for lunch, and I eat lots of pasta and white rice with dinner.

I snack on yoghurt, muesli and the odd bit of fruit. I don't have any health issues apart from mild IBS symptoms sometimes. I'd expect my gut bacteria to be healthy.

EXPERT VERDICT: Malcolm has a strange and unbalanced looking microbiome. Most people have 5 per cent of a bacterium called pseudomonas, but in Malcolm it makes up about half of his gut bacteria - we don't know what triggers it.

In some people, pseudomonas can cause infections affecting the guts or lungs, while in others it's harmless. He is low in firmicutes - an imbalance is linked to poor diet and obesity.

There are some bacteroidetes, which indicate he eats some fibre, but overall his gut is so unbalanced I wonder if he's had an illness or just eats an unhealthy diet high in refined carbs such as white rice or pasta. He also has a slight increase in enterobacteria, associated with inflammation, which is linked to heart disease and cancer and has been implicated in IBS. These inflammation-causing microbes are more common in the obese and those with junk food diets.

GUT HEALTH RATING 5/10

Malcolm says: This is a bit of a surprise. I thought I had a reasonable diet, but when I look more closely I can see it is heavy in refined carbs.

I'd been told my diet lacked fruit and vegetables and had started adding salad to my sandwiches. It's clearly not enough, so I will make much more effort.

JUNK FOOD 'FEEDS' OBESITY BACTERIA

Claudia McGloin, 40, is a single aesthetic nurse who runs clinics in Ireland and London. She is 4 ft 10 in and 10 st 7 lb (BMI: 31.9, obese).

I work long hours and travel a lot. On a typical day I'll skip breakfast, then have a couple of cups of coffee, probably with a bar of chocolate and maybe a packet of crisps.

I'll often skip lunch. I have a big dinner - it could be healthy, such as vegetables and chicken, but when I'm tired I'll often opt for a ready-meal. I'm dreading seeing my results.

Claudia McGloin, 40, is a single aesthetic nurse who runs clinics in Ireland and London. Her microbial profile had an imbalance associated with poor diet and obesity, probably because she eats lots of processed food

EXPERT VERDICT: Claudia's microbial profile is odd. She has very few firmicutes - which normally make up about a third. An imbalance is associated with poor diet and obesity.

People with reduced gut diversity often eat a lot of processed foods. A junk food diet can halve the number of firmicutes in the gut in just ten days.

A junk food diet can halve the number of certain bacteria in the gut in just ten days Professor Tim Spector, King's College London

It seems chemicals in junk food, particularly emulsifiers, kill off good bacteria, allowing unhealthy ones to flourish. Claudia's levels of the pro-inflammatory enterobacteriaceae, also linked to obesity and junk diets, are 50 times the normal level.

In Europeans this bacteria is closely associated with poor health and, in old people, frailty, putting them at risk of falls, hospitalisation and earlier death.

Claudia needs a total reboot of her microbiome. I recommend intermittent fasting, such as the 5:2 diet (where you eat just 500 calories for two days a week). Studies show the more we extend our overnight fast, the more diverse our microbes, the more healthy chemicals are produced and the less weight we gain.

Periods of fasting also lengthen the time our microbes have to rest, strengthening how they interact with our gut lining, which may increase our metabolism. Claudia might also consider probiotics.

GUT HEALTH RATING: 4/10

Claudia says: I thought my results would be bad, but not this bad. It's been the kick-start I needed, and I'm now taking a probiotic, trying the 5:2 diet and exercising more. I feel better already.

FASTING IS GOOD FOR GUT BACTERIA

Martin Welch, 53, is married with three adult children. He is a chief engineer in the automotive industry and lives in Warwickshire. He's 5 ft 8 in and 15 st (BMI: 28, overweight).

Martin Welch, 53, is married with three adult children. He is a chief engineer in the automotive industry and lives in Warwickshire. Eighty-five per cent of Martin's gut bacteria are firmicutes, which is very unusual

I've always been stocky, but have been getting bigger with age.

I'd like to lose weight. I work stressful 12-hour days and grabbing food on the go, such as pizza and pastries, goes with the territory. I don't tend to eat vegetables or much fruit.

I've had digestive problems almost my whole life, with severe pain and bloating after eating. I get a bit of joint pain but I'm rarely ill.

TOP TIPS FOR A HEALTHY GUT If you eat a diverse range of real foods containing plenty of fibre and are happy to experiment, you can’t go far wrong for your gut, says Professor Spector. All vegetables are good, but the very best are the high-fibre root vegetables, particularly the ‘super’ bacteria fertilisers, Jerusalem and globe artichokes, chicory roots, leeks, onions and garlic. Other common vegetables, such as potatoes, are OK if you also eat the skins: sweet potatoes are better, Professor Spector adds. Apples, pears and bananas are good if eaten whole or blended in a smoothie. However their juice alone contains no fibre, so isn’t as healthy a choice. Nuts and seeds, dark chocolate, green tea and coffee also help boost good bacteria. Probiotics have only been shown to clearly work when the gut is very sick due to poor health or antibiotics. It’s a case of trial and error, but look for those containing five to ten billion colony forming units (CFUs). Advertisement

EXPERT VERDICT: This is a very abnormal result - 85 per cent of Martin's gut bacteria are firmicutes. While firmicutes are normal, an imbalance - linked to a junk food diet - can be associated with weight gain.

In Martin's gut they're so dominant other bacteria can't get a look in, which may impair his immune system.

He has particularly low levels of anti-inflammatory faecalibacterium prausnitzii, raising his chance of inflammatory gut conditions and possibly allergies.

I'd say this is the gut bacteria of a man who is unwell or eats a very poor diet, or both. He could also be overweight or have diabetes.

He needs a radical overhaul, going vegetarian for a few months to vary his diet and trying the 5:2 diet.

He could try a probiotic and increase his dairy intake - just a crumb of unpasteurised cheese contains more than ten billion microbes and encourages others to grow.

GUT HEALTH RATING: 2/10

Martin says: I've overhauled my diet based on my result. I'm eating piles of roasted vegetables, taking celery, nuts and soup to work, and eating berries at breakfast. I'm also taking prebiotics containing fibre.

SAUERKRAUT HELPS MICROBE MIX

Kim Pearson, 31, a nutritionist, is single and lives in London. She is 5ft 4in, weighs 8st 8lbs (BMI, 20.5, healthy).

Kim Pearson, 31, a nutritionist, is single and lives in London. She has a diverse, healthy looking gut, with plenty of microbe species associated with high fibre vegetables and fruit

I have a passion for healthy eating. I’ll have a berry, green vegetable and protein smoothie with flax seeds and almond milk for breakfast; I also eat lots of fish, roasted vegetables and salads. I drink wine once a week and eat only organic or grass-fed meat a couple of times a week. I have to watch my weight as it creeps up if I’m not careful.

EXPERT VERDICT: Kim has a diverse, healthy looking gut, with plenty of microbe species associated with high fibre vegetables and fruit. People with these bacteria have a healthier, more diverse gut community and are less prone to diseases.

For instance she has double the average number of bacteriodes and has almost double the normal prevotella; she also has good levels of ruminococcaceae, healthy bacteria often found in people eating lots of fermented foods such as sauerkraut.

Much more unusually, around a quarter of her gut microbes are members of a family called comamonadaceae, usually found in soil – they’re unlikely to be harmful but they are odd.

Does she work outdoors? Or it may be that she’s eating some dirt with her vegetables.

She has three times the average amount of a large group called actinobacteria.

Most people have this, and we aren’t sure how you can reduce the amount you have, but the latest studies show high levels trigger a rapid increase in blood glucose from refined carbs, so if Kim eats these she might me more prone to diabetes or putting on weight.

She should probably avoid over-eating these foods.

Rebecca Coleman, 36, is a solicitor who lives in London with her photographer husband and their daughter, aged three. Her results look 'pretty healthy' and include obesity-reducing microbes

GUT BACTERIA HEALTH RATING: 8/10

Kim says: I’m pleased with my results: the soil bacteria must come from putting raw organic vegetables straight into my blender for my morning smoothie. I might scrub them a bit more now. And Professor Spector is right that I gain weight when I eat carbs.

I was surprised to see the bacteria associated with fermented food as I don’t eat pickles or yoghurt, but realised it must be from drinking miso soup which is made from fermented soybeans.

WHY FASTING CAN HELP

Rebecca Coleman, 36, is a solicitor who lives in London with her photographer husband and their daughter, aged three. She’s 5ft3in, and weighs 10st 7lbs (BMI, 26, overweight).

I try to eat healthily but often end up eating my daughter’s leftovers. However, I also eat plenty of green vegetables. I have recently cut out most carbs, because when I eat them I get some IBS symptoms and I don’t eat dairy because I find it hard to digest. I also suffer from endometriosis, but otherwise feel well.

EXPERT VERDICT: Rebecca’s results look pretty healthy.

She has a bacteria called akkermansia, which is anti-inflammatory, improves blood sugar control and may reduce the risk of obesity and diabetes so I’d be very surprised if this lady is very fat.

People who fast regularly have higher levels of this microbe.

She also has fecobacteriaum prauznizii, one of the most important healthy bacteria involved in making a fatty acid needed for energy for intestinal cells; it also dampens down the immune system, reducing risk of auto-immune disease and possibly allergic reactions. It’s more common in people who eat plenty of fibre.

Rebecca also has good levels of bacteroidetes and prevotella, So I can see she probably eats a high fibre diet and could be vegetarian.

GUT BACTERIA HEALTH RATING: 7/10

Rebecca says: I’m very pleased - and surprised - that my gut bacteria is good despite my minor health issues. I’ve started taking probiotics and digestive enzymes and this has really helped. I’ve also started exercising and now weigh 9st 6lbs (BMI 23, healthy).