This might sound strange but, I promise you, it’s true: until this year, I really hadn’t given my health a second thought.

I say that from the outrageously privileged position of being a 37-year-old woman with no major health issues thus far. I’ve never had an operation, spent the night in hospital or so much as broken a bone. Heck, I can count the number of times I’ve needed antibiotics on one hand.

The vast majority of this is down to sheer good fortune rather than any effort on my part. Sure, I’m a fairly active non-smoker. But, other than that, I have the kind of lifestyle to which the term “train wreck” might be reasonably applied: an ingestion of booze that would prompt a healthcare professional’s eyebrows to rocket skywards were I ever to divulge the real number of weekly units (instead of rounding down and dividing by three); a highly processed diet dominated by the three major food groups of refined sugar, simple carbohydrates and Beige Bits; a roster of frequent late nights offering nothing more than a cursory nod towards the requisite eight hours’ sleep.

And that was before we even got to the hedonism-fuelled bacchanalia that is December, a time in which I ate more, slept less, and replaced the recommended daily water intake with drinks that had the word “mulled” in the name. Yes, I was ostensibly having fun. No, I did not feel good in my body, mind or spirit. I limped towards Christmas fatigued, unmotivated and run-down, oscillating between feverish, frenzied highs and abrupt crashes that left me more zombie than human. Low moods and crying jags, something that had never plagued me previously, were now a feature of my new normal. Fun!

By the time we hit Twixmas, I was desperate for some kind of major lifestyle overhaul; the need for change felt visceral and urgent.

So it was that, for January 2025, I decided to get serious and gear up for the biggest health kick of my life. I would tackle all areas: Dry January went without saying, but I’d also cut out refined sugar and processed foods, embark on a calorie-controlled diet, commit to four workouts a week, attempt eight hours’ kip a night, drink 1.5 litres of water a day, limit myself to one morning coffee… oh, and throw in a selection of daily vitamin supplements for good measure. Go big or go home, right?

The only question was: would it actually make a difference?

Week one

I start as I mean to go on, like the cliched embodiment of a Bridget Jones’s Diary clutch of new year’s resolutions: redistribute the remaining rosé, spend my Christmas money on a diet app, buy an embarrassingly large water bottle emblazoned with intriguing statements like “keep challenge” and “mind your goal”, and splurge a breathtaking sum on vitamins.

After researching the options, I settle on the Fast 800 diet plan. Dreamed up by the late Dr Michael Mosley and backed by a raft of scientific research, it combines fasting with a low-carb, high-protein, Mediterranean-inspired meal plan. The initial stage is hardcore – no breakfast, no snacking, and just two nutritionally balanced meals adding up to around 800 calories a day (the normal recommended allowance for women is 2,000).

As someone who grew up amid the weight loss hysteria of the Nineties and Noughties – I came of age at a time when eating two bowls of Special K a day was seen as a perfectly normal lifestyle choice – this is not my first diet rodeo. But, by the same token, it is the first time I have thought about health holistically instead of simply obsessing over the number on the scales. On previous diets, I had focused purely on calorie counting and calorie deficit – whereby you ensure you consume fewer calories than you burn – and cared not a jot for nutrition. My cupboard was often stacked with grim, empty foods: cardboard-textured crisps, weird-tasting fat-free “yoghurt”, sugar-free fizzy drinks and snack bars of “only 99 calories!” made of God only knows what. But vitamins and minerals? Fibre? Protein? We were barely on first-name terms.

This time it’s different. My real concern is my insides: gut microbiome, heart function, brain, liver and all the other stuff inside this flesh bag that was previously being fuelled by wall-to-wall garbage. The Fast 800 puts the emphasis on eating a fully balanced diet of whole foods, packed with masses of vegetables, protein, whole grains, nuts and dairy. Zero processed foods; zero refined sugar. Even Diet Coke is off the table, to retrain my palate and stop it craving sweet things.

Alongside that, I pound back vitamin C, vitamin D+K, iron and omega 3 oils – all the supplements a nutritionist recommended to me – on the daily. I plan my four exercise sessions a week – one run, one HIIT workout, one yoga class, one Zumba class – and am tucked up in bed by 10pm each night.

The biggest adjustment is the morning routine; there is no breakfast on the Very Fast 800 plan I’m initially subscribed to, the idea being to fast straight through to lunch. As I usually eat the second I’m conscious, this feels a Herculean task. But, as Whitney and Mariah put it, “There can be miracles, when you believe” – possibly about this very scenario, who knows – and so I swap my Crunchy Nut Cornflakes for a mug of ginger tea, pretend it actually tastes of something, ignore the hunger pangs and drink water every time I think about eating. I am peeing like a racehorse and am possibly the most hydrated I’ve ever been.

The week starts strong, with me smugly telling anyone who’ll listen that “it’s honestly not that hard!”, before things take a turn on day four. Brain fog and exhaustion descend – I feel weak, dizzy and incapable of concentrating. For the first time in my adult life, I am unable to sleep through the night, waking at 3am to find myself wired and busting for the loo.

Thankfully, a quick bit of research reveals that all this is pretty normal on a low-carb diet – your body enters ketosis, a state in which it’s burning fat as fuel instead of glucose, and initial side effects include all of the above. It should, fingers crossed, only last a few days.

Elsewhere, I manage to make it through a meal out courtesy of some objectively bizarre ordering (mushrooms with a side of cabbage, anyone?), and get through a full evening at the pub sipping demurely on soda water. At the end of week one, I hop on the scales to find I’ve lost 5lbs. Mostly water, according to the online guidance, but still! Get in.

Week two

I have never cooked or washed up this much in my life. At times, I feel like all I do now is cook things. Wash them up. Cook. Wash up. Cook. Wash up. On a non-stop, interminable cycle. This is because following the Fast 800 involves making all meals – admittedly, for the most part, very tasty meals – from scratch. As someone whose former eating habits were constructed of 60 per cent restaurant dinners, 20 per cent takeaways and 20 per cent Quorn nuggets and potato waffles, this is quite the step-up in terms of time commitment.

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Still, the positives abound: I’ve lost another 3lbs and 9cm off my waist. I’m also through the worst of the ketosis symptoms and am feeling more clear-headed. The sleep is still somewhat broken but steadily improving. Bring. It. On.

Week three

I have developed something my friend and I dub “egg ick”. Following a vegetarian meal plan, I am forced to consume the requisite amount of protein via dizzying amounts of cottage cheese and, yes, eggs. The latter comes in all forms: whipped into omelettes, poached on top of a salad, baked as part of a shakshuka, poured on top of spinach to form a rudimentary Greek spanakopita. By the end of the third week, the mere sight of a sunshine-yellow yolk makes me shudder. I decide to incorporate a bit more fish and dairy and ease off the eggs, just temporarily. At least until my stomach stops churning.

January has so far been an easy month to trial being a teetotaller, but Saturday brings a challenge – some friends are throwing a party at a local karaoke bar. By the time I arrive, everyone is several wines down while I sip meekly on a peppermint tea. (Yes, I order herbal teas in bars now. No, I am not ashamed.) I do the rounds, dance, belt out Alanis Morissette’s “You Oughta Know” with all the gusto I can muster, and decide to call it a night. It is only 10.35pm and I am knackered.

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But I really have started to notice a difference, both internally and externally. Full of a newfound daytime energy, there’s a sharpness to my mind that makes work more enjoyable; my skin is so clear I’ve stopped wearing makeup for half the week. I eat a piece of red pepper and, deprived of refined sugar for three weeks, am practically swooning at its sweetness. I have lost another 5lbs and friends keep telling me how “well” I look.

Week four

I am really and truly in The Zone. Getting up with a herbal tea is second nature (I’ve treated myself to flavours like “gingerbread chai” and “chocolate digestive”, and can almost convince myself they taste like those things). Consuming enough water to comfortably fill a reservoir is a breeze. I’ve got meal planning and batch cooking down pat, and have even come to appreciate the mindfulness inherent in making dishes from scratch rather than microwaving and flopping in front of the TV.

Although I’m struggling to really see the difference in the mirror, maybe because it’s all happened so fast, I get unequivocal proof in the form of my official skinny jeans. We’ve all got them, or an equivalent – an item of clothing that we cling onto, “just in case”, even though it’s nowhere near fitting. Mine haven’t zipped up for more than a year, but I take a punt and shimmy them on. Lo and behold, they fit – it’s a January miracle!

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At a friend’s birthday dinner, I agree to her demand – made at the beginning of the month – that I take one night off sobriety. It feels weird, scandalous even, to top up my glass with white wine and giggle over cocktails. The booze goes straight to my head and the next day is horrendous, haunted by the familiar ghosts of fractious exhaustion and clammy hangxiety. Was I too loud? Too obnoxious? Does everyone hate me? It’s enough to convince me that February should be only the slightest bit damp, if that.

So, scores on the doors time: one month down, has my life really changed?

Well, I’ve lost 16lbs, 11cm off my waist and gone down a dress size. My skin is clearer, my hair shinier. My sleep is deeper, my energy levels consistently higher, and I feel more self-disciplined and motivated across all areas of life. Food tastes better; coffee hits different. My sugar cravings are non-existent.

But the biggest impact of all is the one I least anticipated: my mental health has been utterly, radically transformed. I’ve never before experienced such stable moods, nor such a prolonged period of contentment. I feel a deep-rooted sense of inner peace, positivity and patience that ripples out across every aspect of day-to-day life. I wake each morning with a little internal smile and no longer cry at my desk.

I’m so, so sorry. I hate to be the one to tell you this. But everything you heard is true; doing all the “good things” we know, deep down, we should be doing, actually does change your life for the better. I know. I’m as annoyed as you are.

Probiotics may impact weight and metabolism, but experts are still working to understand the link. Probiotics are friendly microbes that are normally part of the gut microbiome (the community of microbes that live in the intestines). A healthy gut microbiome is important for overall health.

Some initial research shows that certain probiotic strains may support metabolism and promote weight loss by stabilizing insulin levels, reducing inflammation, and controlling appetite.

How Probiotics Affect Body Weight

Taking probiotics can temporarily change the makeup of the microbiome. The strain and dosage of the probiotic may influence the effects. Various strains of probiotics are available as supplements. Not all have been studied for their impact on body weight. Those that have been studied show variable results.

Probiotics may help manage weight by improving the gut microbiome and metabolism in various ways, including:

• Helping stabilize levels of insulin (a hormone that regulates blood glucose levels, enables cells to take in glucose, and promotes storing excess sugars and fats, which can lead to weight gain)
• Stopping the accumulation of fat
• Helping reduce inflammation and insulin resistance (cells do not respond to insulin to take in glucose, resulting in higher blood sugar levels)
• Helping break down fiber and regulating the production of amino acids (building blocks of proteins) in the nervous and digestive systems
• Affecting appetite (a balanced microbiome may influence a series of events in the digestive system that could lead to feeling “full” or reducing appetite)

How Gut Bacteria Affect Metabolism

Metabolism is the process by which the body uses energy to perform body functions. It is an ongoing process that ensures all body systems work, even during sleep. How it works and uses energy (burns calories) changes over time and as a person ages.

Research shows that the makeup of the bacteria in the digestive system affects metabolism. It is still being debated and studied how this happens and which strains of bacteria have what effect. However, the microbiome does influence the metabolic process through cholesterol absorption, blood pressure, and glucose metabolism (how glucose is used and stored).

What Studies Show on Weight Loss and Belly Fat

Much of the research on probiotics and weight has been done on animals. The lack of studies on humans means there isn’t enough information to form recommendations on probiotic supplementation.

One review paper examined six studies on probiotics and overweight or obesity. The studies didn’t all reach the same conclusions about how probiotics affect weight.

In 67% of the studies, participants who took probiotics had lower body weight and body mass index (BMI). In 80% of the studies, people who took probiotics had a reduction in waist circumference.

A few human studies of the probiotic bacterium Lactobacillus gasseri have been reported. In one study, participants who took a supplement of L. gasseri SBT2055 had a decrease in abdominal fat and body weight. Another study showed no change in people who took L. gasseri BNR17.

A study on heat-killed Lactobacillus plantarum LP28 showed that participants lowered their BMI, body fat, and waist circumference. Another study using L. plantarum TENSIA lowered body weight, BMI, and fat mass.

An additional study on Lactobacillus casei strain Shirota (LcS) showed that people taking the probiotic dropped body weight and increased their levels of high-density lipoprotein (HDL) cholesterol (the “good cholesterol”).

Some Probiotics May Also Prevent Weight Gain

Some studies on probiotics also focus on preventing weight gain. Human research is lacking in this area. Much of the research has observed rats and mice. Initial studies on humans have been conducted, but the research results conflict.

If probiotics do help prevent weight gain, one reason might be that they help diversify the gut microbiome.

One review, which included six research papers, examined the use of probiotics to prevent weight gain. It found that products containing multiple strains of Bifidobacterium and Lactobacillus were more likely to show results than other products. 

Probiotic Strains to Try

Research is lacking in determining which probiotics help reduce weight or prevent weight gain. Many of the studies are small in size. It’s not yet known which probiotic will work for which person for the intended effect. Therefore, adding probiotics to the diet might include some trial and error.

At least one research study has shown that the following probiotic bacteria strains help reduce body weight. Most research has focused on strains of Lactobacillus. A few studies have also included Bifidobacterium bacteria. Studied strains include:

• L. gasseri SBT2055
• L. casei strain Shirota
• L. plantarum LP28
• L. plantarum TENSIA
• L. sakei (CJLS03)
• A combination of L. curvatus HY7601 and L. plantarum KY1032
• A combination of L. acidophilus, Bifidobacterium bifidum, B animalis subsp. lactis and L. plantarum)

Potential Risks

It’s important to know that while probiotics are considered safe for most people, they are not without risks.

Some possible risks thought to be of low probability are:

• Systemic infections (the probiotic bacteria invade body tissues or the bloodstream)
• Changing metabolism in an unhelpful or unhealthy way
• Transmission of genes for antibiotic resistance from the probiotic organisms to other organisms in the microbiome
• Overstimulating the immune system

Other risks include:

• Probiotic products not containing what is listed on the packaging
• Interactions with prescription drugs or other supplements
• Gastrointestinal (GI) symptoms

In addition, a few risks are not included in formal studies, but they can occur with any treatment that lacks scientific evidence. The first is financial. Some probiotics can be expensive; taking them for months without results can be considered a waste of money.

Another potential risk is delaying care from a healthcare provider by taking probiotics instead of seeking care. A healthcare provider can provide treatments for obesity, such as exercise, medication, and surgery.

The Best Probiotic Foods for Weight Loss

Eating foods that contain probiotics can be a way to get beneficial gut bacteria. However, solid evidence of how the probiotics in these foods may directly affect weight loss is lacking. But you may reap other benefits. For instance, yogurt that contains probiotics can help lower blood pressure and the risk of heart disease in some people.

Adding probiotic-rich foods to your diet may be an easier and/or less costly way than supplements to work towards a more diverse microbiome. These foods include:

Summary

Weight loss and its connection to the digestive system’s microbiome are complicated and an area of active study. Many unknowns still exist about how the makeup of the gut microbiome affects weight and general health. It is also unknown how individuals might respond to a probiotic supplement.

Probiotic supplements are generally considered safe, but potential risks should be considered. Probiotic foods may also help promote overall health and could be a good choice for those looking to support their microbiome.