Before Covid, before our daily lives changed so dramatically, our immune system wasn’t something most of us thought seriously about – while many people expressed a desire to have a trimmer waistline or wanted to “get healthier”, for example, only would few do talk specifically about how to get your immune system in shape.
However, there is no doubt that fighting infection and disease has taken on a new and urgent meaning as Covid has taken over the planet.
But it’s not just Covid: a fully functional immune system is everything that stands between us and dangerous and life-threatening diseases.
Keep this fact in mind: every day we breathe in between 100,000 and a million microorganisms – a potentially harmful soup made from viruses, bacteria, and fungi – on which our bodies struggle daily with the hordes of pathogens that lurk in what we eat.
While most of us know that our immune systems evolved to deal with dangerous infections, fewer people realize that one of its other main jobs is to destroy early cancer cells before they can get out of hand.
Most of the time you are barely aware of the work of this silent army.
Occasionally, if you cut yourself something like a finger, it can get a little hot, red, and painful. This is a sign of acute inflammation that the body is pushing immune cells to the site of the injury and fighting against possible intruders.
RISKS OF CHRONIC INFLAMMATION
But you can also get chronic inflammation where the immune system remains on high alert for months or even years.
If it stays on high alert, over time the cells of your immune system can begin to damage your blood vessels and other organs.
You can think of it as a civil war going on in your body. Chronic inflammation plays a key role in the development of a number of diseases, from type 2 diabetes to heart disease and cancer. It also undermines your immune system’s ability to destroy dangerous microbes like the virus that causes Covid-19.
So what are some of the main factors that lead to chronic inflammation? At the top of the list is obesity, especially too much fat in the gut. This is one reason why people who are overweight or obese are at a much higher risk of ending up in hospital if they get Covid than people who are slim. Losing weight, especially around the gut, is therefore an important way to reduce chronic inflammation and improve the way your immune system works.
And all week long, I’m going to be showing you simple ways how you can do just that with my Fast 800 Diet.
Every day, the Mail publishes delicious and easy-to-prepare Fast 800 recipes developed by my wife Clare, a family doctor with years of experience helping patients address their health problems through diet – and more recently with a low-carb, low-carb recipe. Calorie approach.
But besides losing weight, there are other ways to strengthen your immune system.
Be kind to the “good guys” in your GUT
One of the best ways to keep your immune system in shape is to eat healthy foods and get adequate amounts of iron, folic acid, selenium, and vitamin C.
While I’m not a fan of nutritional supplements, at this time of year when it’s cold and dark I also replenish vitamin D, the sun vitamin that plays an important role in developing strong immunity. But the effects of your diet on your immune system are far more powerful than just vitamins.
The immune system is incredibly complex. It comprises billions of specialized cells, each of which plays a different role.
There are, for example, macrophages, one of the great guard dogs of the immune system, scavengers, whose job it is to run around and eat anything they suspect (macrophages means “big eater”).
There are also killer T cells, whose job it is to find and destroy cells that have been infected and taken over by dangerous microbes. There are also cells whose job it is to boost an immune response and others whose job it is to suppress it.
And then there is the gut microbiome – the trillions of microbes that live in our large intestines.
The microbiome not only protects your gut from dangerous pathogens that you may have swallowed.
The “good guys” in the microbiome (known in scientific circles as “The Old Friends” because they evolved with us over tens of thousands of years) also play a key role in regulating our immune system.
For example, they convert fibers into a chemical called butyrate, which is great at dampening inflammation.
In addition to the “good” bacteria, there are also microbes in your gut that love junk food and can lead to chronic inflammation.
What is important to your health is diversity, many different types of bacteria – in fact, a low diversity of gut microbes could be a reason some people develop more severe Covid symptoms.
A study recently published in the journal Therapeutic Advances in Gastroenterology, which compared the intestinal bacteria (using stool samples) from 30 Covid patients with 30 healthy people, found that the Covid group had a “significantly reduced bacterial diversity”.
This was not an isolated incident, and other work such as an August article in Virus Research concluded, “The diversity of gut microbiota and the presence of beneficial microorganisms in the gut can play an important role in determining the course of disease. ‘
A healthy mix of gut bacteria doesn’t just affect your chance of catching Covid. Recent research has shown the profound effects of gut bacteria on our physical and mental wellbeing – even on the quality of our sleep.
A study published in PLoS One last year that looked at the habits of 40 men found that people with a more diverse range of intestinal bugs had better sleep than people with a less diverse microbiome.
DITCH THE JUNK FOOD
What’s the best way to make sure you have a healthy, happy microbiome full of old friends?
Genes play a role, but the biggest factor is our diet.
The more restricted your diet, especially when it comes to fiber, the more restricted your gut bacteria are likely to be, and many of us, even without realizing it, limit our intake to a narrow range of similar foods.
Modern ultra-processed foods filled with emulsifiers that are used to extend the life of certain products can reduce the number of helpful types, as can the consumption of junk food.
However, the good news is that you can change the balance of your microbiome – and you can do it in a matter of weeks.
The key is to include many different plant-based foods in your diet as these are high in vitamins and minerals and contain the fiber that helps gut bacteria thrive.
This means that you aim for at least five days a day and make sure you are getting a variety, not just eating the same fruits and vegetables every day.
Data from the British Gut Project, led by Tim Spector, Professor of Genetic Epidemiology at King’s College London, shows that the most important factor in maintaining a healthy microbiome is the consumption of various plants. The more diverse, the healthier our microbiome.
He recommends that we eat 20 to 30 different plants a week – these include fruits, vegetables, nuts, seeds, herbs, and spices – on average, we now eat about five.
Check out Clare’s recipes on these pages – not only are they delicious, but they also feed your “good” bacteria nutrients that will help them thrive. They, in turn, help you stay fit.
- For more information on how the Fast 800 works, visit thefast800.com
Crunch rainbow salad
A colorful salad with an abundance of immune-supporting nutrients and lots of fiber that feed your gut microbiome for healthy production of serotonin (sleep aid).
Served 2 l Prepare for 20 minutes l Cook for 10 minutes
A colorful salad with an abundance of immune support nutrients and lots of fiber to feed your gut microbiome for healthy serotonin production (sleep aid)
PER PORTION 495 cals PROTEIN 13g CARBS 29g FAT 34g FIBER 10.5 g
- 60 g unsalted cashew nuts, roughly chopped
- 3 tbsp mixed seeds (approx. 30 g)
- 250 g red cabbage (about ½ small cabbage), very finely chopped
- 2 medium-sized carrots (approx. 80 g each), cut, washed well and roughly grated
- ½ yellow or red pepper, deseeded and cut into thin slices
- 2 spring onions, cut and thinly sliced
- 1 small eating apple (approx. 90 g), pitted and cut into thin slices
For the dressing
- 2 tbsp extra virgin olive oil
- 1 tbsp mirin (rice wine) or dry sherry
- 1 teaspoon finely grated fresh root ginger
- 2 good pinches of crushed dried chilli flakes
Preheat the oven to 200c / 180c fan / gas 6.
Sprinkle the nuts over a baking sheet and fry for 5 minutes. Add the mixed seeds and cook for another 3 to 5 minutes, or until the nuts and seeds are lightly toasted. Put aside. You don’t have to roast the nuts and seeds, but they’ll taste better when you do.
Whisk all the ingredients for the dressing in a large bowl.
Add the cabbage, carrots, peppers, green onions, and apple and toss them all together.
Sprinkle over the nuts and seeds to serve.
Sprouts and Bacon
Such a simple little vegetable has gotten a bad rap, but Brussels sprouts are high in fiber and have a nutritious side that complements any protein. Fiber feeds your gut microbiome and affects your serotonin production and your ability to convert it to melatonin – the hormone responsible for sleep.
Served 2 l prepare for 5 minutes l cook for 10 minutes

Such a simple little vegetable has gotten a bad rap, but Brussels sprouts are high in fiber and have a nutritious side that complements any protein
PER PORTION 174 cals PROTEIN 11g CARBS 5g FAT 11g FIBER 7g
- 2 teaspoons of olive or rapeseed oil
- 2 slices of smoked bacon (approx. 75 g), cut into 1-2 cm pieces
- 250 g small Brussels sprouts, cut and halved
- Salt and freshly ground black pepper
Heat 1 teaspoon of oil in a large non-stick pan, add the bacon and fry over medium heat for 2-3 minutes or until lightly browned, stirring regularly. Transfer to a plate with a slotted spoon.
Add the remaining oil and sprouts to the pan, reduce the heat slightly and fry for 4-6 minutes, or until brown and tender, stirring frequently.
Put the bacon back in the pan, sprinkle over vinegar, salt and plenty of pepper. Throw 1 minute.
Chickpea patties
Chickpeas are a rich source of vitamins, minerals, and fiber. They feed your gut microbiome to support your immune system and sleep processes.
Prepare for 4 l 15 minutes l cook for 10 minutes

Chickpeas are a rich source of vitamins, minerals, and fiber. They feed your gut microbiome to support your immune system and sleep processes
PER PORTION 200 cals PROTEIN 8g CARBS 15g FAT 11g FIBER 5g
- 2 tbsp coconut / rapeseed oil
- 1 medium-red onion, peeled and finely chopped
- 15 g fresh root ginger, peeled and finely grated
- 2 cloves of garlic, peeled and finely grated
- 1½ tsp medium curry powder or Garam Masala
- 1-2 teaspoons of shredded dried chilli flakes (optional)
- Drain 1 x 400 g of chickpeas
- 20 g plain peanuts, coarsely ground
- Salt and freshly ground black pepper
- 1 tbsp whole wheat flour
- 15g bunch of fresh coriander, leaves finely chopped, plus
- 1 red chilli, finely chopped, for serving
Heat 1 tablespoon of oil in a medium saucepan over low to medium heat. Add the onion and sauté for 4 minutes or until tender, stirring regularly.
Add the ginger, garlic, curry powder, and chilli flakes, if used, and cook for another 1 minute, stirring constantly.
Remove from heat, add the chickpeas to the pan, add the tahini and peanuts and mash with a potato masher until the chickpeas turn into a thick paste and clump together (this should take a few minutes).
Put in a bowl, season well with salt and ground black pepper, add flour and chopped coriander and mix well.
Shape the mixture into 8 patties and press firmly to hold them in shape.
Heat the remaining oil in a large non-stick pan over medium heat. Add the patties and saute them for about 5 minutes or until golden brown and crispy.
Serve 2 patties per person with some chilli, if used, a lime wedge, coriander leaves and a large green salad.
Fennel and pak choi
Pak Choi and Fennel boost your soluble and insoluble fiber intake to feed all of the healthy microbes in your gut that support your immune system.
For 2 liters of preparation boil 10 minutes l 15 minutes

Pak Choi and Fennel boost your soluble and insoluble fiber intake to feed all of the healthy microbes in your gut that support your immune system
PER PORTION 93 cals PROTEIN 2g CARBS 6 g FAT 6 g FIBER 4g
- ½ medium onion, peeled and thinly sliced
- ½ medium-sized fennel bulb, cut and thinly sliced
- Medium Pak Choi, cut and leaves separated
- 15 g fresh root ginger (approx. 2 cm), peeled and finely chopped
- Salt and freshly ground black pepper
- Lemon wedges for serving (optional)
In a large non-stick pan, heat the oil, add the onion and fennel, and sauté over low to medium heat for 8 minutes or until the fennel softens, stirring occasionally.
Add the pak choi and ginger and cook for 5 minutes or until the stems are crispy and soft and rotate regularly. Season with salt and pepper and add a pinch of lemon to serve.
A pan of miso eggplant
Miso is full of essential minerals and, as a fermented food, contains probiotics to support the gut microbiome. This dish shows you how to use it as more than just a soup.
For 2 liters of preparation boil 10 minutes l 40 minutes

Miso is full of essential minerals and, as a fermented food, contains probiotics to support the gut microbiome. This dish shows you how to use it as more than just a soup
PER PORTION 421 cals PROTEIN 21.3 g CARBS 28.2 g FAT 22.3 g FIBER 11.3 g
- 2 teaspoons of extra virgin olive oil
- 20 g fresh root ginger, peeled and finely grated
- ½ teaspoon of shredded dried chilli flakes
- 50 g plain peanuts or cashew nuts, roughly chopped
- 2 spring onions, sliced and finely chopped
- 1 red chilli, finely chopped, for serving
Preheat the oven to 200c / 180c fan / gas 6 and line a baking sheet with foil.
Cut the eggplants in half lengthwise and cut the meat back and forth without cutting through to the skin.
Place on the baking sheet, cut with the side up and brush with the oil. Bake for about 30 minutes or until softened and lightly browned.
In the meantime, mix the miso paste with soy sauce, ginger and chilli flakes in a small bowl. In a separate bowl, combine the peanuts and green onions.
Take the baking sheet out of the oven and spread the eggplants with the miso mixture.
Scatter the spring onions and peanuts on top and spread the frozen edamame around the eggplant on the tray.
Return to the oven for another 8-10 minutes or until the peanuts are lightly browned and the edamame are hot.
Sprinkle over the chillies to serve. You can scoop the roasted eggplant out of the pods as you eat – better yet, eat the pods too.
Simple roasted vegetables
The more color there is on your plate, the more diverse the nutrients – and that with a selection of Mediterranean vegetables that feed your immune system and your gut microbiome.
For 4 liters of preparation boil 10 minutes l 40 minutes

The more color there is on your plate, the more diverse the nutrients – and that with a selection of Mediterranean vegetables that feed your immune system and your gut microbiome
PER PORTION 153 cals PROTEIN 3.5 g CARBS 12g FAT 9g FIBER 5g
- 3 peppers, each color, pitted and cut into 2 cm pieces
- 2 medium-sized zucchini, cut into 2 cm pieces
- 2 medium-red onions, peeled and cut into 8 thin wedges
- 2 tbsp extra virgin olive oil plus extra for drizzling (optional)
- Salt and freshly ground black pepper
- 1 tbsp fresh thyme leaves, 2-3 sprigs or 1 teaspoon dried thyme
Preheat the oven to 200c / 180c fan / gas. 6. Put all the vegetables in a large bowl and mix with the oil.
Season with a large pinch of salt and plenty of ground black pepper. Sprinkle in one layer over a large baking sheet and fry for 25 minutes.
Remove from the oven, sprinkle with the thyme and turn all the vegetables.
Return to the oven for another 5 minutes or until lightly browned. Take out of the oven and drizzle with some extra virgin olive oil just before serving, if you like (add the extra calories for each teaspoon).
Could Bad Bowel Bugs Cause Mood Swings?
The idea that the gut microbiome, the bacteria that live in our intestines, could affect your mood may sound unlikely – but there is plenty of new research showing that that’s exactly what happens.
Indeed, the study of how the creatures in our intestines affect our brains has its own name: “psychobiotics”.
But how do tiny microbes that live in your colon affect your brain? Simply put, they are brilliant chemists. Some of them can convert the foods our bodies can’t digest (like fiber) into hormones like dopamine, serotonin, and GABA (a chemical messenger that works similar to the anti-anxiety drug Valium).

The microbes in our intestines can also “speak” to our brain via a network of nerve cells that line our intestinal walls and are connected to the brain via the vagus nerve.
The microbes in our intestines can also “talk” to our brain through a network of nerve cells that line our intestinal walls and are connected to the brain via the vagus nerve.
Thanks to the revolutionary work of Professor Felice Jacka, the dynamic director of the Food & Mood Center at Deakin University in Melbourne, Australia, we also know that changing your diet (and therefore your microbiome) can really affect your mood.
I first came across her work in 2017 when she published the results of the SMILES study, the first real study to investigate whether healthier eating could improve depression.
For the study, she randomly assigned people with moderate or severe depression to either a Mediterranean diet or a standard plan.
Those following a Mediterranean-style diet were also asked to eat less unhealthy foods such as sweets, refined cereals, fast foods, processed meats, and sugary drinks.
The effects on those who changed their diets have been profound. Many who were able to stop taking medication were no longer classified as “depressed”. The fact that it was those who made the biggest changes in their diet who saw the biggest improvements in their mental health strongly suggests that it was the change in diet that made the difference.
One of the participants, who had already tried unsuccessfully to discuss therapy and medication, later said to the professor: “The program was a last resort for me. I am forever grateful for his success. “
Other studies have since confirmed their results, and I now believe that one of the best ways to improve our mental health and make us happier is by following better diet – happy bowel bugs, happy life!
Pay attention to the use of confectionery
People often ask if they can use sweeteners instead of sugar on the Fast 800 diet.
The problem with sweeteners is that most of them damage the good microbes in your gut (the colony of bacteria that live in your large intestine). These good bacteria are important for digestive health and immunity – which is obviously a particular concern at this point.
Sweeteners are also many times sweeter than sugar, which means that regardless of their low calorie content, they can keep your sweet tooth and increase your sugar cravings. Fortunately, during the Fast 800 Easy Diet, you’ll find that your sense of taste changes, and you can enjoy treats with much less sugar as your taste buds adjust.
In some recipes we use dried and fresh fruits such as dates, figs, bananas and apricots as natural sweeteners. Unlike sugar, which contains empty calories, fruit adds fiber and a host of important vitamins and other nutrients.
If you really need to have a little bit of sweetener, especially for the first week or two while you’re resetting your sweet tooth, then stevia is probably your best bet.
The Fast 800 Easy by Dr. Clare Bailey and Justine Pattison, edited by Short Books, £ 16.99. Copyright © 2021 Dr. Clare Bailey and Justine Pattison. For information on purchasing a copy for as little as € 7.99 (RRP € 16.99) online or at a WHSmith store, see page 48. Terms apply.